Monday, December 31, 2007

Law Round the Bend, Says Fined Physicist

Y'know, I kept thinking that it's only going to be a matter of time before something like this happens, and it has (at least it is the first time I've seen reported in the news media). A physicist is challenging his speeding fine that was based on a "speed camera".


Dr Fielden, 41, said: "Speed cameras are designed only to work on a straight line. As a physicist, I know that radars, which the cameras use, travel in straight lines. If you set one up on a curve, it is going to be inaccurate."


I wish the news report had more details on this "speed camera", i.e. how it determines the speed of a vehicle. If all it does is detects either "incoming" or "outgoing" motion, then there's something not quite right with this physicist's argument. Let's say it has a radar-type detection that can only detect how fast something is coming or going away from it. Now, if a vehicle is going at 30 mph but going around a bend, the speed detected will ALWAYS be less than 30 mph. One can see this if one looks at a vehicle moving in a circular motion. Only when it is moving in a tangential path towards where the detector is will it register the actual speed. At other locations along the circular path, the speed that the object is either moving towards or away from the detector will always be less than the actual speed.

So if this physicist was caught with a speed of 36 mph while going around in a bend, then if the scenario that I've argued here is correct, it means that he was actually going FASTER than 36 mph, which wouldn't help his case. But like I have said, it depends on how the speed is detected here. Without knowing anything more, I'm just making speculation on how this is done. Does anyone else know how such a "speed camera" work?

Zz.

Saturday, December 29, 2007

How a Catholic Priest Gave Us the Big Bang Theory

This is a rather interesting article on Georges Lemaitre, a Catholic priest who, this article claim, to have been the first who originated the "Big Bang Theory" of cosmology. You might want to read this and judge for yourself if it is accurate.

I have no issues with such claims. However, I do have a problem with the underlying tone of the article. It appears as if the author of the article tries very hard to imply that the Big Bang Theory itself has "religious" origins, simply because the first person who made such a scenario happens to be a catholic priest. That's as absurd as the Nazi during World War II trying to erase Einstein's Theory of Relativity because it had "Jewish" elements. It seems that Lemaitre was being just a good scientist and examined the evidence available at that time to come up with a scientific description, something that Galileo had done a long time ago. Even the article itself described this process:


Returning to Belgium in 1925, where he worked at the Catholic University of Leuven as a part-time lecturer, his big break came two years later in 1927 when he proposed his theory of an expanding Universe to explain the movement of the galaxies, published in the Annals of the Scientific Society of Brussels.


In other words, he came up with the theory to explain the observation, and not based on some pre-conceived religious view of the universe. The fact that he happened to be a catholic priest is incidental and irrelevant, at least from the story. I would bet that the paper that he published never cited any religious sources to justify the impetus for the theory.

Strangely enough, while the author wants christians to "take credit" for the Big Bang theory, he seems to have ignored the incompatibility between the cosmological age of the universe based on the Big Bang Theory, and the biblical age of the universe that various christians sects have stuck to. I mean, 14 billion years old is hugely different than 60,000 years old! Even if one were to fudge a few numbers here and there, and make rough estimates of many things, there's no way one can make those two numbers approach even remotely the same order of magnitude. To me, this also points to the "non-religious" origin of the Big Bang theory in cosmology.

To associate the origin and impetus of a theory simply to the religion of the originator is taking a rather large leap of logic. Unless one can specifically cite the exact impetus that subsequently becomes the theory, then simply using the argument that a theory has catholic origin because so-and-so is catholic is logically faulty.

Zz.

Friday, December 28, 2007

Andrew M. Sessler Posdoctoral Fellowship for Excellence in Accelerator Research

A fellowship for anyone going into Accelerator physics.


The Accelerator and Fusion Research Division (AFRD) at Lawrence Berkeley National Laboratory (LBNL) invites applications for the Andrew M. Sessler Postdoctoral Fellowship for excellence in accelerator research. The research is to be carried out within AFRD's Center for Beam Physics (CBP) and/or the Lasers, Optical Accelerator Systems Integrated Studies (LOASIS) Program, and offers the successful applicant the opportunity to work in a rich scientific environment at the forefront of a broad range of accelerator physics studies. Ongoing research activities include experimental and theoretical work with applications in near-term and future projects, and the successful applicant will be expected to make significant contributions to one or more areas, depending on experience and interests.

The Sessler Fellow will have the opportunity to choose topics of original research in consultation with members of CBP and LOASIS. The Sessler Fellowship is for a two-year term. For more information and to apply, please go to *http://jobs.lbl.gov*, select "Search Jobs," and enter job number *21132* in the keyword search field. Once you have located the position, click "Apply Now" and follow the online instructions. Applications must be received by January 11, 2008. LBNL is an equal opportunity employer with a commitment to workplace diversity.


Zz.

Stephen Hawking Joins Attack on Science Cuts

Is it just a mere awful coincidence or was it planned that both the UK and the US suddenly decided to make a severe slash of physics funding almost at the same time?

With the UK slashing major parts of its high energy and astrophysics/astronomy projects, it has practically ended its participation in the International Linear Collider project. Physicists in the UK have denounced this cutbacks and have started an online petition. Stephen Hawking is the last one to join this list.

Zz.

NOvA Project on Hold in Wake of Budget Cuts

More fallout of the recent Omnibus spending bill that has just been signed by President Bush. The NOvA neutrino project is now on hold after it was, get this, flat-lined in the budget. It means that it got NO MONEY whatsoever. The project now is currently on hold, when it should be starting construction this coming year.

The sad thing about this is that this is just nothing more than nickle-and-diming. It is a drop in the bucket when compared to the whole budget, and yet, it has such a huge ramification in terms of the US involvement in high energy physics.

They probably thought they are "saving money" from a project that isn't important, without realizing the damage they are doing.

Zz.

Thursday, December 27, 2007

American Scientists 2008 Stamps

The US Post Office has announced a slew of new stamps for 2008. The series on American Scientists this coming year will include John Bardeen and Edwin Hubble.

American Scientists

Some of the most impressive scientific achievements of the 20th century will be recognized in April when the American Scientists stamps are issued. The series honors four scientists:

-- Theoretical physicist John Bardeen (1908-1991) co-invented the transistor, arguably the most important invention of the 20th century. Bardeen also collaborated on the first fundamental explanation of superconductivity at low temperatures, a theory which has had a profound impact on many fields of physics.

-- Biochemist Gerty Cori (1896-1957), in collaboration with her husband Carl, made important discoveries that later became the basis for our knowledge of how cells use food and convert it into energy. Among her discoveries was a new derivative of glucose, a finding that elucidated the steps of carbohydrate metabolism. Their work also contributed to the understanding and treatment of diabetes and other metabolic diseases.

-- Astronomer Edwin Hubble (1889-1953) played a pivotal role in deciphering the vast and complex nature of the universe. His meticulous studies of spiral nebulae proved the existence of galaxies other than our own Milky Way, paving the way for a revolutionary new understanding that the cosmos contains myriad separate galaxies, or "island universes."

-- Structural chemist Linus Pauling (1901-1994) determined the nature of the chemical bond linking atoms into molecules. He routinely crossed disciplinary boundaries throughout his career and made significant contributions in several diverse fields. His pioneering work on protein structure was critical in establishing the field of molecular biology and his studies of hemoglobin led to many findings, including the
classification of sickle cell anemia as a molecular disease.

For each stamp, artist Victor Stabin of Jim Thorpe, PA, with the assistance of art director Carl Herrman of Carlsbad, CA, created a collage featuring a painted portrait of each scientist combined with diagrams or photographic representations associated with their major contributions.


I'm glad to see that John Bardeen is being recognized, considering that many still are not familiar with his name.

Zz.

More Bad Physics

OK, Christmas is over. So no more peace and goodwill towards others. It's time we get back to exposing bad physics!

:)

First of all, I know this is just nitpicking, but I'm in the mood to do one, so here goes a nitpicking.

This blog article in a newspaper describes what the author believe to be the difference in perception of other drivers depending on what car one is driving. He's comparing how he sees other drivers around him react if he's driving a big old Mercury Grand Marquis versus a small car. One of the reason he gave for such differences is this:

First, the size of the car. The bigger the car, the more damage it can do in an accident at any given speed. That is simple physics of energy equals mass times velocity. Not that I think most people are really aware of that.


Well, I'd say not a lot of physicists are aware of that either. "mass times velocity" is MOMENTUM, not "energy".

Like I said, this is nitpicking. However, this is BASIC, simple physics that any high-schoolers would have learned. One should not get something this simple, or this obvious, wrong.

Zz.

Wednesday, December 26, 2007

Hospitals Chase a Nuclear Tool to Fight Cancer

This is a New York Times article on the rush of a number of hospitals to build a proton therapy center to treat a number of diseases. I'm not so sure if one can call these things a "nuclear" facility rather than a particle physics facility. Whatever it is, the physics of these facilities are what is done in the field of Accelerator Physics, not nuclear or particle physics. So I thought I should point out another application of accelerator physics that was never mentioned in the article.

So next time the US Govt. decides to fund only the Medical/Biological/Health/etc. aspect of science, where do they think the equipment and facilities those scientists benefited from originated?

Zz.

Tuesday, December 25, 2007

Hurting U.S. Research Labs

A "Letter to the Editor" in the New York Times by Leon Lederman regarding the devastating impact on the recent US Omnibus bill. It ends with something that could be a distinct possibility, and which something the US Govt. needs to decide now.

Before World War II, American scientists had to go to Europe to get their graduate degrees and participate in the revolutionary physics of the atom. Is it our leaders’ wisdom that this epoch should be repeated?


Zz.

Monday, December 24, 2007

The Physics of Christmas

With Santa expecting to arrive tonight, here's a recap of something I posted last year at this time of the year.

The Physics of Santa discusses how the jolly old guy will complete his task tonight. There is also another article that discusses this, so you can compare them. On a newer front, this website on About.com has all the physics you want to know associated with Christmas. And here's another article on the physics of santa, including the aerodynamics question on how he could fly.

Plenty of stuff to read if you are bored with the holidays. :)

Happy Holidays everyone!

Zz.

Sunday, December 23, 2007

Illinois Delegation Responds To Fermilab's Predicament

This has been distributed for immediate release:

December 21, 2007

DURBIN, OBAMA, BIGGERT CALL ON BUSH ADMINISTRATION TO INCREASE FUNDING AT FERMILAB

In light of recent funding cuts, Illinois members will meet to discuss strategy

WASHINGTON, D.C. – U.S. Senators Dick Durbin (D-IL) and Barack Obama (D-IL) and Representative Judy Biggert (R-IL) today sent the following letter to Jim Nussle, Director of the Office of Management and Budget (OMB), calling on him to increase next year’s funding for the High Energy Physics (HEP) program, which supports research at Fermilab in Illinois, and at several other laboratories and universities across the nation that are doing vital, cutting edge research.

Durbin, Obama, and Biggert are in discussions with Congressional appropriations and authorization committees and the Department of Energy to address the current funding situation and avoid potential layoffs during fiscal year 2008. They also plan to call for an Illinois delegation meeting in January with representatives from Illinois labs and organizations to discuss a strategy to avoid potential job loss at Fermilab. The spending bill, approved by Congress this week, provided the HEP program with $88 million less than was requested. This challenges Fermilab's ability to remain one
of the world's preeminent research facilities after it has achieved outstanding success in research on neutrinos, the high energy frontier, and particle astrophysics.

Adequate funding for the labs is critical to ensure that our country maintains its technological edge and that we continue to add to our high-tech manufacturing base. Fermilab is the nation’s premier high-energy physics laboratory. The laboratory leads U.S. research into the fundamental nature of matter and energy, and in 2007, Fermilab’s researchers and facilities achieved results judged by the American Institute of Physics as among the Ten Top Physics Stories from around the world.

-30-

[text of the letter is below]

Dear Director Nussle:

We are writing to you concerning a matter of critical importance to our country, to science in America, and to our global competitiveness. As you continue to develop the President’s Budget for Fiscal Year 2009, we respectfully request that you increase funding for the High Energy Physics (HEP) program in the Office of Science at the Department of Energy.

As you know, the budget approved this week by Congress dealt a severe blow to HEP, which received $88 million less than requested. This budget rejected funding for the NOvA neutrino experiment at Fermilab, and drastically cut funding for research and development on the International Linear Collider. These cuts could cripple Fermilab's ability to remain one of the world's preeminent research facilities. And this is at a time when Fermilab has achieved outstanding success, with significant results in each of its central areas of research: neutrinos, the high energy frontier, and particle astrophysics.

The facilities at Fermilab are essential for the basic scientific research that nurtures technological and scientific advances, and that fuels American innovation. Fermilab is one of a handful of our nation's premier training sites for scientists, and a centerpiece of the system of DOE National Laboratories. Disruptive funding
shortfalls have ripple effects throughout the American scientific community, displacing today's scientists and discouraging tomorrow's. We must work together to restore funding in basic physics research to maintain America's role as the innovator in technology, to retain our leading scientific institutions and their skilled workforces, and to provide opportunities for future scientists.

While we recognize the formidable challenges you face regarding the demands on the federal budget, we respectfully encourage you to increase the funding request for the Office of Science, particularly for the HEP program, in the President’s FY2009 Budget.

Sincerely,

Barack Obama
Richard J. Durbin
Judy Biggert


One hopes that they can do something not just for Fermilab, but for high energy physics funding in general. In the scheme of things, $88 million is merely pittance and does not make or break the US budget, especially in light of the humongous defense spending. We we are nickle-and-diming things here. Yet, that small amount means survival or closure of many HEP research projects. Like I said earlier, if Fermilab survives this, none of the current members of Congress (save for Judy Biggert) deserves to bask in any of Fermilab's future glory, because they tried to kill it.

Zz.

Saturday, December 22, 2007

Instead of Celebrating Christmas, Would You Celebrate Newtonmas?

This is a rather amusing article on Wired Blog. While Dec. 25th is more popularly associated with Christmas, it is also the date that Isaac Newton was born. The author puts forth a suggestion that we should take this opportunity to teach the kids some basic physics to celebrate Newton's birthday.

I think it's a great idea!

Zz.

Friday, December 21, 2007

The APS Press Release On The 2008 Omnibus Spending Bill

The American Physical Society put out a press release in response to the disastrous US spending bill.

APS Urges Congress and White House to Revisit Fiscal Year 2008 Science Funding in January

Current legislation is disastrous for U.S. physical sciences and technology enterprise.

(Press release issued 4:45 pm, December 19, 2007)

The American Physical Society, representing more than 46,000 physicists in universities, industry and national laboratories, regards the fiscal year 2008 omnibus spending bill as extraordinarily damaging to the nation's science and technology enterprise. The bill fails to fund appropriately the research and education programs authorized in the bipartisan America COMPETES Act, which President Bush signed into law only four months ago. The consequential layoffs of scientists and engineers throughout the nation will discourage American youth from pursuing these fields, just as the country needs their participation to sustain economic growth and national security.

While other nations are aggressively challenging American leadership in physical sciences and technology, the omnibus bill sets our country on the wrong course. It fails to provide the necessary resources for long- term research in the physical sciences and engineering. It fails to provide the requisite resources for developing new cutting-edge scientific laboratories and even for operating existing national user facilities. It fails to provide adequate funding for university- based research that is so essential for educating the next generation of scientists and engineers. It also fails to provide the appropriate incentives for American industry to innovate at an accelerated pace.

Furthermore, as we as a nation strive to reduce our dependence on foreign oil, mitigate global warming and put a lid on escalating energy costs, the omnibus bill abandons the long- term transformational research that is necessary to achieve all these essential goals. The bill is bad for our energy future and economic future.

Finally, apart from its failings on global competitiveness and energy, the omnibus legislation also places at grave risk committed U.S. participation in two large international scientific collaborations. Just one year ago, the United States made a major commitment to the construction of the International Thermonuclear Experimental Reactor (ITER). Today, Congress has pulled the plug. In so doing, it critically damages American credibility as a reliable scientific partner throughout the world and compromises the nation's standing as a host of future international scientific facilities. Congress has also cut the lifeline of the International Linear Collider, which represents the future of American high- energy physics. This action sends a strong message to the world: The U.S. is prepared to jettison support for one of our flagship areas of science that probes fundamental laws of the universe.

The APS notes with some dismay that had Congress applied the same discipline to earmarking as it did last year, the damage to the science and technology enterprise could have been avoided.

For these reasons, the American Physical Society strongly urges Congress and the White House to revisit Fiscal Year 2008 science funding after Congress convenes in January with an eye to reflecting better the nation's long term needs and obligations.


... and here are more news coverage on the disaster that will take into effect at Fermilab starting in January. I tell ya, if they survive this, and that there are new discoveries made at Fermilab, none of the current legislator should attend to bask in the glory, because all of them tried to kill not only this laboratory, but also high energy physics.

Zz.

Introduction to the Photon Collider

With the International Linear Collider (ILC) on life-support system due to the pull-out of the United Kingdom and the severe funding slash by the US Congress, maybe it is a bit moot to talk about possible experiments at the ILC. Still, it one can always dream of what could have been. The ILC would certainly be the most logical facility to start considering the possibility of having a photon collider. This article gives a rather thorough "introduction" to the physics we gain out of a photon collider.

Ah, the good old days of optimism.....

Zz.

It Only Takes Two

This is a rather interesting and provocative conclusion. A group of physicists in Brazil have claimed that we only need a minimum of 2 fundamental constants to be able to arrive at all the other constants, thus, to describe our universe. {Link may be open for a limited time}

The two can be chosen, according to taste, from a list of three: the speed of light, the strength of gravity, and Planck’s constant, which relates the energy to the frequency of a particle of light, say George Matsas of the São Paulo State University and his colleagues.

Once two constants have been chosen from that list, they say, those are the only parameters that need have units of measurement ascribed to them. Everything else — for example, the charge or the mass of an electron, or the strength of nuclear forces — can be described in relation to these two 'dimensional' constants.


So far, as far as I know, this work hasn't been published yet, only appearing on the e-print arXiv. So we will have to wait until it does to see the kind of reaction and feedback it will get.

It would be interesting to compare this to an earlier manuscript titled "Trialogue on the number of fundamental constants" by M. J. Duff, L. B. Okun, G. Veneziano, where they also argue with each other on the actual number of fundamental constants that is really needed to describe our universe. It certainly would make a very interesting reading if one is getting sick of the upcoming holiday festivities!

:)

Zz.

Thursday, December 20, 2007

Fermilab Is In Deep, Deep Trouble

I mentioned earlier about the spending bill that just passed the US House of Representative. This news article from Science's website clearly spells out the doom and gloom picture at Fermilab. While we all know that the Tevatron will shut down after 2009, Fermilab as a facility had hoped to remain as a high-energy physics laboratory via its neutrino experiment, which include the upcoming NOvA.

Now, even its survival as a laboratory is in question after the proposed severe cuts in the budget. But I think what is frustrating is that most people would just wish that those who are in power would just make up their freaking minds! I think this sums up best:

The budget decisions, part of a $550 billion omnibus spending package that Congress approved this week, call into question the U.S.'s commitment to particle physics as a whole, says Fermilab Director Pier Oddone. "There's a policy question for the government and for Congress," he says. "Do we want to stay in particle physics or not?"


They need to decide now because with the LHC looming in the near future, they either should give sufficient funding, or simply declare that the US will no longer be in particle physics and close up shop. This way, they can take the "credit" later on in the history of human civilization as being the group of legislator responsible for killing high energy physics work in the US. Maybe that is something they want to be proud of.

Edit: More related news story on this matter.

Zz.

Wednesday, December 19, 2007

Ten Top Physics Stories for 2007

The Physics News Update at the AIP has compiled a list of their Top 10 physics stories of 2007.

I think I covered most of them on here this year! :)

Zz.

Ampere Could Be Defined One Electron At A Time

This is another very clever technique and experiment.

The Ampere unit might possibly be defined more accurately using a single-electron transistor.

The current flowing through the device is simply the number of electrons that tunnel per gate cycle multiplied by the charge of the electron and the frequency of the gate voltage. The gate frequency and number of electrons per cycle can be determined and the charge on the electron is fixed – which means that the device is a very precise source of current.

The team believe that the device could form the basis of a "metrological current pump", which could be used to define the ampere from the fact that


Very nice!

Zz.

The Religious and Other Beliefs of Americans

I thought that during this "joyous" time of the year with the holidays approaching, that I throw in a piece of coal into the celebration by bringing some depressing statistics (just call me the Grinch that is trying to ruin Christmas).

This Harris poll was just recently published, and a follow up to its earlier similar poll in 2005. It asked about the beliefs (religious or otherwise) of Americans. Here are some of the interesting results:

* 82 percent of adult Americans believe in God – unchanged since the question was last asked in 2005;
* Large majorities of the public believe in miracles (79%), heaven (75%), angels (74%), that Jesus is God or the son of God (72%), the resurrection of Jesus (70%), the survival of the soul after death (69%), hell (62%), the devil (62%), and the virgin birth (Jesus born of Mary) (60%);
* Roughly equal numbers – both minorities - believe in Darwin’s theory of evolution (42%) and creationism (39%);
* Sizeable minorities believe in ghosts (41%), UFOs (35%), witches (31%), astrology (29%) and reincarnation (21%);
* While many of these numbers for people who hold these beliefs are the same or little changed from 2005, the overall trend is upwards with slightly more people believing in miracles, angels and witches than did so two years ago.


So, compare that with the survey on science literacy of the public that was conducted by the National Academies, and you now have a very clear idea of the kind of public you are dealing with as far as science is concerned. Just something to think about during the festive season.

:)

Zz.

From High Temperature Superconductivity to Quantum Spin Liquid: Progress in Strong Correlation Physics

This is a fascinating review article by Patrick Lee of MIT[1], even if you don't agree with his take on the mechanism of cuprate superconductivity. He covers the outstanding issue in strongly-correlated electron system, which is the main area of study in condensed matter physics since it covers essentially that whole field of study.

What is interesting is that at the end of the article, he has a question-answer section that addresses specific issues and his take on the answer. This is always something I like to read because even if you disagree with him, at least you know clearly where he stands and why he disagrees. In many instances, it can be vague on what exactly people are disagreeing on. Here, it is rather clear.

In any case, I would think anyone in this field of study would want to read this article. At the very least, it'll get you up to speed on the theoretical progress in this area.

Zz.

[1] P.A. Lee, Rep. Prog. Phys. v.71, p.012501 (2008).

Tuesday, December 18, 2007

New Budget A Blow to Physics Funding

The budget that was passed in the USHouse of Representatives, and that President Bush intended to sign, is a MAJOR SETBACK for physics, and especially High Energy Physics funding.

The ILC effort was severely reduced, and zero money has been allocated for the NOvA project at the Tevatron. This is horrendous!

With all the talk about trying to make US more competitive, etc... etc.. and all the initiatives to raise funding for basic science, they all come to zilch.

Zz.

Using Physics to Learn Mathematica to Do Physics

About a week ago, I highlighted a physics education paper that studied the impact of using symbolic mathematical software packages such as Mathematica on the way physics students think about physics problems. It was an enjoyable reading.

This time, there is another paper on using Mathematica specifically in advanced undergraduate physics classes. The author describes how Mathematica is used in junior-senior level physics courses. Too bad he does not have the same transcript of the students' struggle with solving the problems. :)

Zz.

Laws Of Nature, Source Unknown

I have mixed feelings after reading this article. On one hand, it is a compact, brief summary of the differing opinions among physicists on the issues surrounding how we comprehend our world. On the other hand, I don't think someone without a good background in physics would read it with the same comprehension as a physicist, and that could create a whole different perspective that may not be entirely accurate.

The problem here is that it is trying to "describe" the problem using a series of short, quick quotations from various sources. Such a thing is never accurate, especially on something as complex as this. This is where a physicist read this does see the actual physics associated with the quote being shown, while the general public ONLY see the quote and take it at face value without realizing the underlying physics. This is where the differing perspective from reading the same article comes from.

Still, I suppose this is an interesting enough article. At least, it reminded me again that hilarious quote attributed to Feynman:

These kinds of speculation are fun, but they are not science, yet. “Philosophy of science is about as useful to scientists as ornithology is to birds,” goes the saying attributed to Richard Feynman, the late Caltech Nobelist, and repeated by Dr. Weinberg.


I have to remember to use that one of these days. :)

Zz.

Monday, December 17, 2007

Photonic Crystal Bends Light Round Corners

Another cool experiment that has plenty of possible application. A photonic band gap material has been fabricated to cause light to be directed around as if it is in a waveguide.

Paul Braun and colleagues at the University of Illinois at Urbana Champaign have pioneered a flexible process for a fabricating 3D photonic-crystal waveguide by using a focused laser to mark it out.


Zz.

The Physics of Magic Carpet

Just when you thought you've read everything....

It seems that physicists at Harvard, no less, have found an aerodynamics solution in which one can make a "carpet" fly.

The researchers have studied1 the aerodynamics of a flexible, rippling sheet moving through a fluid, and find that it should be possible to make one that will stay aloft in air.

No such carpet is going to ferry people around, though. The researchers say that to stay afloat in air, a sheet measuring about 10 centimetres long and 0.1 millimetres thick would need to vibrate at about 10 hertz with an amplitude of about 0.25 millimetres. Making a heavier carpet 'fly' is not forbidden by the laws of physics. But the researchers say that their "computations and scaling laws suggest it will remain in the magical, mystical and virtual realm", as the engine driving the necessary vibrations would need to be so powerful.


I will stick to commercial airlines, though. Just think how difficult it is to eat powdered doughnuts during an open-air magic carpet ride? :)

Zz.

Sunday, December 16, 2007

Compact Synchrotron Is Unveiled

This is another advancement in the wakefield accelerating technique for particle accelerators. This time, using a laser plasma wakefield and an undulator, they have managed to create the same type of radiation produced at large synchrotron centers (free registration required to view article), all inside a standard-sized laboratory.

Now, Dino Jaroszynski of Strathclyde University in the UK, together with colleagues at Friedrich-Schiller-Universität in Jena, Germany, and Stellenbosch University in South Africa are the first to have combined a laser-driven plasma wakefield accelerator with an undulator to make a compact source of synchrotron radiation.

The team’s wakefield accelerator can accelerate electrons to 1 GeV, which can create X-ray synchrotron radiation with a very narrow bandwidth. What's more, the wavelength of the radiation can be tuned from the far infrared (terahertz frequencies) to hard X-rays by simply changing the energy of the electron beam.


Such technique, such as plasma wakefield, laser-plasma wakefield, and dielectric wakefield, are show more promises of being a feasible technique for new acceleration scheme. The next few years should be very interesting, especially if the delay in the ILC might cause some people to start thinking of other accelerating structures.

Zz.

Saturday, December 15, 2007

Lee Teng Undergraduate Internship in Accelerator Science and Engineering

Lee Teng is a distinguished physicist in accelerator physics and received the Wilson award at this year's Particle Accelerator Conference.

An internship in his honor has be set up for undergraduates intending to go into accelerator physics. The following is the official announcement:

Applications are now being accepted for the Summer 2008 Lee Teng Undergraduate Internship in Accelerator Science and Engineering, sponsored jointly by Argonne National Laboratory, the Fermi National Accelerator Laboratory and the US Partice Accelerator School.

The internship will provide a unique research opportunity to select students from US universities who are currently in their Junior year in physics, engineering, or computer science. Each intern will work closely with a mentor from one of the two laboratories on a project related to accelerator science and/or engineering.

The ten week program includes a generous stipend, as well as travel and housing allowances. In addition, the program includes full tuition and travel expenses to the two week US Particle Accelerator School, which will be held at the University of Maryland. For more information and to apply, visit www.illinoisacceleratorinstitute.org

Vladimir D. Shiltsev
Director, Accelerator Physics Center
FNAL, PO Box 500, MS221
Batavia, IL 60510 USA
Ph. +1(630)840-5241
Fax +1(630)840-6039


Zz.

The Tiny, Mighty Transistor

The transistor turns 60 this coming week. This news article describes the importance and the impact of the invention of the transistor in our digital world of modern electronics.


A transistor is a little electronic switch capable of amplifying electric current, invented by John Bardeen, Walter Brattain and William Shockley at Bell Labs in New Jersey on Dec. 16, 1947. They jury-rigged the first transistor using a paper clip, some germanium and gold foil, and found that it boosted electrical current a hundredfold. They kept the discovery to themselves for a bit, and showed their bosses the device just before Christmas. Bardeen, Brattain and Shockley won the Nobel Prize for physics in 1956.


Of course, I've mentioned this earlier in the context of the most under-rated physicist of them all, John Bardeen, who I consider to be http://physicsandphysicists.blogspot.com/2006/09/most-influential-physicist.html.

Zz.

Friday, December 14, 2007

Rising Above "The Gathering Storm"

This promises to be a fascinating, if not provocative, reading reading with the issue of science education and the perceived shortage of qualified scientists and engineers in the US.

If you're familiar with the report from the US National Academies titled "Rising Above the Gathering Storm: Energizing and Employing America for a Brighter Economic Future", you would have read the gloomy outlook for America's competitiveness in science and engineering. In most cases, this was a very influential report and has produced several legislative actions to halt this decline.

Now, however, comes a report from another organization that challenges this perception. A report titled "Into the Eye of the Storm: Assessing the Evidence on Science and Engineering Education, Quality, and Workforce Demand" by the Urban Institute, a policy-research organization, points out several inconsistencies of the first "Gathering Storm" report.

You may read more about this conflict (and read the reports yourself) at this Science Career webpage. It would be interesting to see if the National Academies write a response to this new development.

Zz.

Stored Light in an Optical Fiber via Stimulated Brillouin Scattering

A new paper appearing in this week's Science[1] advances the possible practical application of storing light pulses and using it at later. This time, light pulses in an optical fiber are converted to slow-moving vibrations in the fiber itself, before converting it back into light. The efficiency of the conversion depends only on the lifetime of the acoustic vibration.

What is different than the earlier light-storing scheme done by Lene Hau is that this technique doesn't employ purely quantum-mechanical phenomena and thus, is more robust. it can't do some of the exotic gymnastics that the other earlier techniques can do, but at the same time, it is relatively easy to implement, using standard equipment already available and works at room temperature. Further, it can work on any frequency of light that is transparent to the fiber, whereas the atomic/resonator technique of storing light so far is restricted to only one particular frequency.

A review of this work can be found here (link may be open without restrictions only for a limited time).

Zz.

[1] Z. Zhu et al, Science v.318, p.1748 (2007).

Snow and Ice Crystals

It's winter around here (at least, for most of us in the upper Northern hemisphere). So what better time to read about snow and ice crystals. It is a good quick study on snow and ice crystals from this month's issue of Physics Today. It's everything you wanted to know about such a thing within 5 minutes, but were afraid to ask! :)

Zz.

Thursday, December 13, 2007

ILC Reference Design Report Volume 1 - Executive Summary

I don't know if this is now moot, especially after the future of ILC is in jeopardy with the pullout of the United Kingdom, which is a major blow to the ILC effort. Still, if you're interested, this is Volume 1 of the ILC Design Report Executive Summary. It should tell you everything you wanted to know about the ILC design, but were afraid to ask.

:)

Zz.

Wednesday, December 12, 2007

Bill Foster for Congress

OK, politics.

It is no surprise that the US legislators lack scientific expertise. As far as I know, only 2 members of the US Congress are scientists. Well, let's hope there could be one more addition to that.

I received this e-mail from the Bill Foster for Congress campaign.

There has never been a more important time to improve the quality of scientific and technical judgment in our government. I am asking for your support as a scientist who has taken up this challenge – specifically, by campaigning for the now-open seat of former Speaker J. Dennis Hastert in the U.S. Congress.

Dennis Hastert has now resigned from Congress and a Special Election is scheduled for March 8, 2008.

This election offers a rare opportunity to send a clear signal of national disapproval for the continuation of the policies of President Bush and a Republican party that refuses to change course.

Since I announced my candidacy in May 2007, 24 Nobel Laureates have endorsed my campaign and we are making news. Over 650 scientists from across the country have so far contributed to our campaign.

Political endorsements for the campaign include Illinois Senator Dick Durbin, the Majority Whip in the U.S. Senate.

Like many other scientists, I have felt the frustration of a government that has abandoned the basic principles that we in the scientific community take for granted. Logic, reason, and demonstrable facts have been suppressed and ignored by an administration and congress more interested in pleasing its ideological patrons than in governing effectively. Our country will be suffering the consequences for decades.

In addition to the War in Iraq, our nation faces complex issues in energy policy, arms control, global warming, cost-effective delivery of health care, intellectual property rights, and individual privacy in the age of networked computers. Stem cell research represents only the leading edge of a wave of issues that will challenge and divide the most thoughtful of us – but has been used so far only as a political football in the abortion rights debate. Essentially every issue we face has a technological edge to it, and there is no substitute for adequate scientific competence in congress.

I believe that my background as both a successful physicist and businessman makes me well qualified to address the economic and technological challenges we face.

* As a particle physicist, I worked 22 years at Fermi National Accelerator Laboratory where I was involved in the discovery of the Top quark and the design and construction of the latest of Fermilab’s giant synchrotrons.
More information: Foster08.com/about/?id=science
* Before becoming a scientist, I was a successful businessman. When I was 19 years old, my younger brother and I started a company in our basement that now manufactures about 70% of the theater lighting equipment in the United States.
More information: Foster08.com/about/?id=business

A competent, dedicated, and experienced campaign staff has been assembled to win this race. Polling data is favorable. The hard-eyed political viability of this campaign is addressed in our campaign prospectus Foster08.com/cp (.pdf version)

HOW YOU CAN HELP

· Contribute to the campaign at www.foster08.com/donate

· Endorse the campaign at http://www.foster08.com/action/endorse.cfm

· Sign up for our newsletter at http://www.foster08.com/action/emailalerts.cfm

It is no secret that winning a campaign in our democracy requires money. Many thousands of personal telephone calls by the candidate are typically required to raise the millions of dollars needed to wage a competitive congressional campaign. The necessity of fundraising has been a major barrier to the participation of more scientists and others in our democracy. You generous support lowers that barrier, and will encourage other scientists to follow the path to public service.

More information can be obtained at www.foster08.com

I look forward to your strong support.

Sincerely,

Bill Foster
Candidate for Congress (IL-14)


Looks like he has a clear vision of what he wishes to accomplish.

Zz.

Free For All For Particle Physics Journals?

There's a movement to make all journals publishing particle/high energy physics papers to be open accessed.

The issue surrounding this isn't as trivial as it might appear, as one can read in the article itself. While such an aim might be feasible for high energy physics, it is still an open question if it can be done with other fields, such as condensed matter which produces probably the largest percentage of published papers. There aren't a lot of "large groups" in condensed matter, and most research work are done by small groups with small budgets.

Zz.

Disagreement Over Fractal Technique In Pollock's Painting Isn't Over

.. and not by a long shot.

Recall earlier that I mentioned that the fractal analysis technique used to "authenticate" a Jackson Pollock's art has been discredited. Most of us thought that was the end of that. Not so fast...

It appears that the original authors have posted a rebuttal to this. Read it for yourself to see if you're convinced. I am sure that the Jones-Smith et al. camp will be reading this carefully and it would not surprise me if they have a response to this rebuttal.

So stay tune, the fun may not be over just yet! :)

Zz.

Neutrino Physics

This is a review article on the latest news in the field of neutrino physics by S. King. The comment says that this is suitable for a general audience. Don't you believe that! :) A general PHYSICS audience, maybe, but not the general public.

Still, anyone with a physics background might find this highly useful to get caught up in the fast-moving area of study in neutrino physics.

Zz.

ScienceDebate2008

With the US Presidential election looming, the whole political process has been active for the past few months. However, one conspicuous element here is missing - a clear view on the candidates' science and technology knowledge and policy. As usual, science takes a back seat (way back) in these matters.

Lawrence Krauss and Chris Mooney want to change that. They are organizing a ScienceDebate2008 for the presidential candidates.

This fact -- combined with the undisputed importance of scientific research and innovation to national prosperity and competitiveness -- explains the recent emergence of a group called ScienceDebate2008. Under its auspices, scientists, university presidents, industry leaders, elected representatives and others have endorsed a call for the current U.S. presidential candidates to participate in a debate, or a series of debates, dedicated to issues in science and technology. More specifically, the candidates should answer questions about the environment, medicine and health, and science and technology policy.


I hope this takes off. However, I don't quite know how big of an influence it would be to the general public. Are these the issues that would sway their votes one way or the other? Would the perceived importance of science be a factor when these candidates debate about science issues?

Zz.

Tuesday, December 11, 2007

UK Pulls Out Of The ILC

This is a MAJOR bombshell and could spell doom to the International Linear Collider project.

The United Kingdom has decided to pull out of the ILC due to budget cutbacks.

The ILC, which will collide beams of electrons and positrons, is being planned as the next accelerator following the Large Hadron Collider, which is set to come online at CERN in 2008. The UK has played a significant role in building the LHC and the withdrawal will come as a blow for the particle-physics community.


The US, via the Dept. of Energy, has already indicated that no decision on the building of the ILC will be made before 2020 (or even later), prompting Fermilab to come up with an interim Project X. With the withdrawl of the UK, would the US (or maybe Japan) be next to pull out? Any one of these countries pulling out will signal the death of the ILC, I would think.

Zz.

Relativity Visualized

I came across this paper in the European Journal of Physics:

"First-person visualizations of the special and general theory of relativity", U. Kraus, Eur. J. Phys. v.29, p.1 (2007).

The author presents a description of a class in which he tries to impart a visualization of various aspects of Special and General Relativity. I suppose this can make the conceptually-difficult aspects of Relativity easier to illustrate. But what is neat is that he also have a website that has all of these illustrations.

You can check out all the visualizations yourself. Some of them are in German, but from what I've read, more English versions are coming.

This website might be useful to students trying to learn Special and General Relativity.

Zz.

Monday, December 10, 2007

Symbolic Manipulators Affect Mathematical Mindsets

This preprint is a rather "entertaining" reading, and you don't say that very often with things like this.

This work examines the impact of the availability of symbolic calculators, such as Mathematica, on physics students. It appears that the students are more "free" to explore the mathematical solutions using different paths. However, the study concluded that the students appears to not be able to make the connection between the mathematics and the physical meaning of the mathematics.

The students show admirable flexibility and creativity as they try different calculation strategies and representational forms. Rather, the difficulties associated with Mathematica use appears to arise from more subtle issues. They arise from a local coherence in their thinking that leads them to focus on computational aspects of the problem while suppressing the connection with the physics and with extended mathematical meanings.


I got very fascinated with several of the transcripts of the conversation between the students as they struggle to solve physics problems. I just hope they knew they were being recorded. :)

Zz.

UK Physics Professors Criticise Cuts in Budget

Looks like all those promises of more support for science funding in the UK isn't coming true.

Professors from Cambridge, Oxford and more than 20 other universities issued an unprecedented statement criticising ministerial plans to cut scientific research grants by 25 per cent over the next three years.


That is dreadful.

Zz.

Physics Laws Flawed?!

Not so fast, Mister!

There is a major concern when a news report doesn't do a COMPLETE reporting and make it appear as if this is a done deal.

One of the continuing controversy and continuing area that is still being investigated is the idea that the fine structure constant might be different during the earlier time of the universe than what it is now. Most of the evidence that seems to point to such possible variation has come from astrophysical observation, whereas most of the terrestrial-based observations have placed a more stringent upper limit on possible such variation.

This news report is presenting the "rebuttal" from the J.K. Webb camp[1] of a paper by Srianand et al.[2] that contradicted their earlier report[3].

Physicists have been chasing results like these for a number of years, but since 1999, Murphy and his co-researchers have been ahead of the pack. They’ve published a series of observations from the Keck Telescope in Hawaii as further evidence of a varying fine structure constant. But, a few years ago, another research team claimed that data from a different telescope contradicted Murphy’s observations.

However, he’s been able to prove that the contradictory work itself was flawed. “We’ve shown that the way the data was analysed was faulty,” he said. “Their procedures were faulty so the numbers that came out are meaningless. Our paper points this out. When you replicate their analysis and fix their problems, you get a very very different answer indeed.”


This is fine and dandy. However, by leaving it as is, it gives a very misleading impression that this "proof" done by them is a done deal. This is false because in the same issue of PRL, Srianand et al. gave their own comment[4] against the analysis done by Murphy et al. In it, they made the argument on why they stand by their earlier results.

Regardless on who you believe, this issue isn't settled, especially considering the nature of the "evidence" and the degree of certainty. This is certainly different than the impression one gets after reading this news article. It is unfortunate that they only reported on the first comment but not on the response to that comment. Someone has not been doing his/her homework on this.

Zz.

[1] M.T. Murphy et al. Phys. Rev. Lett. v.99, p.239001 (2007).
[2] R. Srianand et al. Phys. Rev. Lett. v.92, p.121302 (2004).
[3] J.K. Webb et al., Phys. Rev. Lett. v.82, p.884 (1999).
[4] R. Srianand et al., Phys. Rev. Lett. v.99, p.239002 (2007).

Sunday, December 09, 2007

Oppeneimer Comes To The Opera

I mentioned earlier that Dr. Atomic will be making its operatic debut at the Chicago Lyric Opera this coming January. The Chicago Tribune has a preview of this work that is currently in rehearsal.

I'm not much of an opera buff, but I am certainly considering attending this one. It isn't often that there's something related to either physics or physicists on stage. The last one that I attended was "Copenhagen" on Broadway, and it was outstanding. So if this is as good as the original review of the San Francisco premier, maybe I can sit through an opera for a couple of hours. :)

Zz.

Saturday, December 08, 2007

Woman to Lead SLAC

It's sad that in 2007, we still have headlines when a woman is appointed for a top position. Still, this is a noteworthy accomplishment. Persis Drell has been appointed as the new director of the Stanford Linear Accelerator laboratory. This comes at such an important turning point in SLAC's history as it morphed itself from a high-energy particle collider into a light source.

It is a bit amusing that the San Jose Mercury News that this news report came from is still calling SLAC as an "atom smasher". It's transformation into the LCLS smashers nothing at all. :)

Zz.

Knot Physics

This is the kind of "string" theory that I can deal with. :)

A couple of physicists have studied how a piece of string eventually end up with knots, and how that depends on its length.

In the end, one law emerged: The longer the string, the more likely it is to form a knot. String that was 1.5 feet or shorter never got tangled up. But “as the string gets longer, the probability of a knot forming goes up and up,” Smith says, at least to 18 feet. Flexibility matters, too. The more pliable the string, the more likely it is to knot spontaneously.


I'm not quite sure how such a knowledge would be useful elsewhere (topology?).

Zz.

Friday, December 07, 2007

Dark Energy: The Decade Ahead

This is a terrific article on the physics of Dark Energy, and what we can expect in the next decade or so. It was written by two of the leading figures in this field, Eric Linder and Saul Perlmutter.

There's also a rather good article on the history of the discovery of the accelerating universe that led to the idea of dark energy. It was written by Robert Crease. Not only is the story interesting, but it tells you of the workings and the competition between different groups within the same field and trying to study almost the same thing.

Zz.

Thursday, December 06, 2007

No, Science Does Not 'Rest On Faith'

This is a very pointed and sharp rebuttal to Paul Davis' New York Times essay that claimed that science also practice a degree of "faith".

The public and repeatable testing of hypotheses distinguishes science as the most successful form of inquiry ever. Among other things it shows that it is officially not in the business of accepting anything "without question, without examining the grounds". Davies and others who describe science as "ultimately resting on faith" are thus not only wrong but do much irresponsible harm to it thereby.


I very much agree. I think it is highly irresponsible to make such a statement, because those who seek to undermine science will use it without understanding the differences.

Zz.

Major Physics Breakthrough In Understanding Supersolidity

I guess one of the major news of this week is the new discovery of the sheer modulus characteristic of a He in the "supersolid" phase[1] (assuming that it did become a supersolid).

Day and Dr. Beamish have taken this research a different direction. In an experiment not done before, they cooled the solid helium and manipulated the material another way -- by shearing it elastically. In doing so, they found that the solid behaved in an entirely new and unexpected way -- it became much stiffer at the lowest temperatures.


A perspective of this work in Nature[2] has a bit more info:

A supersolid can exhibit other anomalies, for instance in the speed at which sound passes through it. Sound speed depends on the shear modulus of the solid, as well as the density of the superfluid component. To assess why the solid behaves in the way it does, it is thus important to measure the shear modulus independently of the superfluid density. This is precisely what Day and Beamish have now done with solid helium.

Again, the authors' experiment3 is conceptually simple. They placed solid 4He between two parallel plates, known as piezoelectric shear transducers. They moved one plate, the driving transducer, in a direction parallel to the second plate. The solid helium transmits the resulting elastic shear stress between the plates, and this is measured by the second transducer. Day and Beamish find3 that the shear modulus of helium rises by up to 10% as the temperature is reduced from 0.2 to 0.02 kelvin. More significantly, the temperature dependence of this large increase in shear modulus closely tracks the changes in period in the torsional-oscillator experiments.


Fascinating stuff coming out of supersolidity lately.

Zz.

[1] J. Day and J. Beamish, Nature v.450, p.853 (2007).
[2] A.T. Dorsey and D. A. Huse, Nature v.450, p.800 (2007).

Wednesday, December 05, 2007

String Theory In the Era Of The Large Hadron Collider

Whether you buy into String Theory or not, this is a good article to read in this month's issue of Physics Today. Michael Dine discusses the issues surrounding String Theory, and whether the LHC can produce anything to verify String Theory.

Zz.

Tuesday, December 04, 2007

Physics of Information: From Entanglement to Black Holes

So, if you're in Waterloo, Canada tomorrow (Dec. 5th, 2007), you might want to see if you can attend this. It sounds like such a fun thing to do for physics geeks! :)


Do ideas about information and reality inspire fruitful new approaches to the hardest problems of modern physics? What can we learn about the paradoxes of quantum mechanics, the beginning of the universe and our understanding of black holes by thinking about the very essence of information? The answers to these questions are surprising and enlightening, but also controversial. The topic of information within physics has involved some of the 20th century’s greatest scientists in long-running intellectual battles that continue to the present day. In this special debate, hosted by the CBC’s Bob McDonald of ‘Quirks and Quarks’, you will enjoy a lively discussion between four prominent physicists who have thought long and hard about these questions.


With a high-powered panalist consisting of Anthony Leggett, Leonard Susskind, Seth Lloyd, and Chris Fuchs, this discussion could be very fascinating.

Zz.

Girl Power Dominates at Siemens Competition

For the first time ever, the girls swept the competition at this year's 9th Annual Siemens Math, Science, and Technology Competition.


With their work on a new treatment for tuberculosis, Janelle Schlossberger and Amanda Marinoff, both 17-year-old seniors, became the third straight team from Plainview-Old Bethpage John F. Kennedy HS to make it to the finals - but the first from the school to win the prestigious competition.
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Isha Jain, 16, of Freedom HS in Bethlehem, took the top individual prize for her ground-breaking research on bone growth in zebrafish, which could lead to better understanding of bone disorders and injuries in humans.


Hum... so I've noticed that it is "easier" to win this competition when one's project is in biology/medicine. Not that easy to carry out a physics project that can wow the judges, is it?

Zz.

Monday, December 03, 2007

A Different Universe: Reinventing Physics from the Bottom Down

I have mentioned many times on the issue of emergent phenomena, why the so-called Theory of Everything may be nothing more than a TOE for reductionism, and the arguments put forth by Robert Laughlin regarding this. I have also highlighted his book on such emergent phenomena.

An excerpt of this book is one of the essay on PhysicsCentral. So if you haven't read it yet, this might give you a "flavor" on what he is tackling. I wish they had done a longer excerpt, because the issue of collective behavior and emergent phenomena are only covered in the final paragraph. I believe is PNAS paper and his Nobel Prize speech have a lot more "teeth" in his argument.

In any case, you should really read the whole book if you haven't come across such argument before.

Zz.

Sunday, December 02, 2007

The Race To Study Dark Energy

This news article describes the competition and race to be the one selected to design and build the necessary observatory to study dark energy. It gives some idea not only of the problem at hand, but also a feel for what usually is involved in science when such a large (and expensive) project is involved. Many things have to occur first (workshops, pre-proposals, etc.. etc..) before something is selected and the green light to build is given.

And even then, you still don't know that you'll get to the finish line, as can be seen with the Superconducting Supercollider, and the Alpha Magnetic Spectrometer.

Zz.

Saturday, December 01, 2007

Neutrinos Could Probe Earth’s Structure

This is certainly an ambitious proposal, but not that outrageous in terms of implementation.

A group of physicists have proposed to use the atmospheric neutrinos to study the structure of our Earth.

Now, Concepcion Gonzalez-Garcia from the University of Barcelona in Spain and colleagues say that atmospheric neutrinos may have been dismissed too hastily. Their calculations show that, although the proportion of atmospheric neutrinos above the 10 TeV absorption criterion is low, the sheer number of them could make up for it (arXiv:0711.0745). “It would be better to have a localized beam rather than a disperse one, but the point is that there is no such localized beam in nature that is intense enough,” Gonzalez-Garcia told physicsworld.com.


They hope to detect these few events at IceCube, the neutrino detector project at the South Pole.

It sounds daunting, but who knows.

Zz.

$1.5 Billion Space Experiment Could Be Grounded

I mentioned earlier the cancellation by NASA to bring the Alpha Magnetic Spectrometer into orbit at the International Space Station. This is the latest news coverage on this.

It is too bad that the one project that could almost justify the building of the ISS is the one that is being canceled.

Zz.

Friday, November 30, 2007

The Science of The Pirates of the Caribbean

I love it when two of the things that I'm passionate about merges. It has happened a few times before, such as when it was discovered that Enrico Fermi actually used words and characters from the Winnie the Pooh (OK, so that isn't exactly Disney) to label some of his work, or the physics in Pixar's animation.

So here's another example. It appears that Western Illinois University has been organizing a science night for the public. It is usually themed, and this time, it is a presentation of the science coming out of Disney's Pirates of the Caribbean movie.

Thursday's event featured movie clips from the "Pirates of the Caribbean" movies with related experiments, such as the physics of the movie's fight scenes, mystery ships, weight distribution and even a few small explosions using simple ingredients such as Diet Coke and Mentos candy.

One student made a rocket sled propelled by a fire extinguisher, while another used an inhaled gas to deepen two students voices more to a "pirate" tone. The final event was the favorite as liquid nitrogen was mixed with heavy cream and other ingredients to make ice cream for the crowd.


I suppose you gotta try everything you can to make science entertaining to the public.

Zz.

Thursday, November 29, 2007

Debye Was Not An Anti-Semite Or A Nazi

This is rather interesting, mainly because I missed the whole controversy in the first place. A news report in Science's daily news update based on a thorough investigation historian Martijn Eickhoff of the Netherlands Institute for War Documentation appears to have exonerated Peter Debye of being a Nazi and an anti-Semite. The allegations were made by physicist and journalist Sybe Rispens in a book and in a magazine article titled "Nobel Laureate With Dirty Hands".

The 200-page study by historian Martijn Eickhoff of the Netherlands Institute for War Documentation, commissioned by the Dutch science ministry and published yesterday, concludes that Rispens's picture of Debye was a "caricature" that contains multiple errors. Eickhoff points out that Debye seemed to think that he had to do what he could to keep German physics afloat. Although he didn't actively resist the Nazi regime, there were "moments of opposition," the study notes, such as his helping two Jewish colleagues escape from Germany. To retain his position, he developed a "survival mechanism of ambiguity."


The full report in English can be found here.

Zz.

Krauss Explains His Remarks

There are two lessons here:

1. Don't read New Scientist (I don't)
2. Physicists should pay attention to what they say before saying it.

I highlighted the terrific article by Helen Quinn in Physics Today several months ago. In it, she plea for us to pay attention to the words and phrases we use, because such things can be easily misconstrued by the media and the general public. I think Lawrence Krauss should have paid attention to this relevant essay before he sat down for the interview with any New Scientist reporter.

This, of course, came about because Krauss gave an interview that caused even experts in cosmology to scratch their heads. He made headlines when the said to the effect that we somehow are hastening the demise of the universe simply by observing dark energy, and equating it to an aspect of quantum mechanics in how an observer affects a system simply by observing it. When this came out, of course all the news media picked it up.

You'll notice that I did not report it here at all, till now. Oh, I definitely read it the day it came out, but way in the beginning, I noticed that it came out of New Scientist (that has the propensity to reach for sensationalism more than accuracy), and that the statement itself is nonsense. I half-heartedly was hoping that Krauss was pulling an Alan Sokal with New Scientist. Alas, I won't be getting such pleasures.

Krauss has now clarified what he wanted to say, and what he meant. It certainly isn't what was written in New Scientist, I can tell you that.

"I was too glib," the scientist said in a phone interview. "I had just completed this paper about a subject that I found so fascinating, and I was excited to talk to another scientist about it. But I was running off to Nashville from California. And I didn't spend enough time explaining myself."
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But Krauss admitted that he had gotten caught up in his excitement about quantum mechanics and should have chosen his words more carefully. What he meant, he said, is that by observing dark energy, scientists might have pinpointed more accurately where the universe is in its evolution - and that it might be less stable than we thought.


Let this be a lesson to every scientist. I myself have learned such a lesson a while back, although on a significantly lesser scale than what Krauss is going through. The public that you're talking to does not understand science, and certainly cannot put into context the words that you are using. They will take it at face value, and you'd better have an extra pair of ears listening to what you are saying before you let it through.

Zz.

Wednesday, November 28, 2007

Sheep Collisions: the Good, the Bad, and the TBI

I seldom try to "advertise" a paper on arXiv that is yet to be published, but I just found this a fascinating read and an amusing one as well.

The authors of this preprint are trying to show how an analysis in Halliday and Resnick on why 2 sheep can survive a violent head-butting without suffering any brain injury is not actually correct. The subject matter is rather amusing (at least to me), but there's some rather good basic mechanics issue here being presented, especially for motion without the assumption of a constant acceleration. So I think any physics undergraduate that have had sufficient calculus can follow this.

Now, anyone willing to read it carefully enough to see if they've done the physics correctly? :)

Zz.

Schrodinger's Kittens Enter The Classical World

This is a rather fascinating angle on the quantum to classical transition. The traditional explanation on the cause of the difference between quantum world and the classical world is the onset of decoherence, where the system interacts with its environment. That interaction with the large degree of freedom causes the emergence of our familiar classical world. We have seen several experiments that showed that the onset of such decoherence gave us back the familiar classical description. In fact, it has been shown that even with just ONE interaction, a single-particle system can quickly lose its quantum coherence.

However, a new theoretical research has taken a different angle. Two physicists in Austria has published a paper[1] showing that the emergence of classical observation can be also be obtained without having any decoherence effect, but rather due to the "coarse-grained" measurement that we make. A review of this work was reported in Nature Daily News (the link may be available for a limited time and may require registration and/or subscription).

Johannes Kofler and ÄŒaslav Brukner of the University of Vienna and the Institute of Quantum Optics and Quantum Information, also in Vienna, say that the emergence of the 'classical' laws of physics, deduced by the likes of Galileo and Newton, from quantum rules happens not as objects get bigger, but because of the ways we measure these objects. If we could make every measurement with as much precision as we liked, there would be no classical world at all, they say.


We know that "size" isn't the issue here, especially with the recent SQUID experiments of Delft and Stony Brook. However, the conventional thinking is that the larger the size, the more difficult it is to maintain coherence of all the parts of the system. What the new approach here has tried to explain is that with the larger size, the precision of our measurement also tends to get worse. Unfortunately, their proposal to measure and detect the quantum effects on large system appears to be rather daunting, if not almost-impossible.

Kofler says that we should be able to see this transition between classical and quantum behaviour. The transition would be curious: classical behaviour would be punctuated by occasional quantum jumps, so that, say, the compass needle would mostly rotate smoothly, but sometimes jump instantaneously.

But watching such quantum jumps between life and death for Schrödinger’s cat would require that we be able to measure precisely an impractically large number of quantum states. For a 'cat' containing 1020 quantum particles, say, we would need to be able to tell the difference between 1010 states – too many to be feasible.


Still, I wouldn't put it past some experimentalists coming up with an ingenious way to test this.

Zz.

[1] J. Kofler and C. Brukner, Phys. Rev. Lett. v.99, p.180403 (2007).

Tuesday, November 27, 2007

More Tests of Leggett Inequality

Earlier, I highlighted the paper by the Zeilinger's group that rules out a class of realism model via the violation of the Leggett inequality. Now comes two more papers in last week's Phys. Rev. Lett. that made further tests of such violation.

The first one is more of a refinement of their earlier work from the Zeilinger's group. This one supposedly rules out a larger class of local realism model without the assumed rotational symmetry of the earlier tests.

T. Paterek et al. "Experimental Test of Non-Local Realistic Theories Without The Rotational Symmetry Assumption", Phys. Rev. Lett. 99, 210406 (2007).

The second paper in the same issue also tests the Leggett inequality and finds a clear violation of it.

Cyril Branciard et al. " Experimental Falsification of Leggett's Nonlocal Variable Model", Phys. Rev. Lett. 99, 210407 (2007).

It is amazing that tests after tests all produce a consistent result that are in full agreement with quantum mechanics. At some point, this will become a very convincing body of evidence.

Zz.

Monday, November 26, 2007

A Teacher In Perpetual Motion

So why can't we all get teachers like Micheal Lampert when we were in high school?

The demonstrations highlight Lampert's skill at bringing science to life and his ability to tailor lessons to different learning levels.

"He's just a master to watch in the classroom as he instills in students a real interest in science," principal Ed John says.


The most profound part of this whole article is what he himself believe to be the most effective means of teaching:

"The only thing that's successful with these kids is to be one-on-one with them and talk to them. That's the secret to bringing out learning," he says.


It is unfortunate that many schools cannot only afford such luxury, but also the luxury of having a physics teacher with a great physics training and background.

Still, I think I've discovered the most effective means of making students interested in physics!

Lampert has made a big impression on microelectronics student Ian Love, 15. "Once, he used a high-voltage transformer that took wall current, stuck both electrodes into a hot dog and fried the hot dog," Ian says. "It was like an electrocution of the hot dog. I can't wait to take his physics class next year."


Electrocute a hot dog! That's all you need! They'll be eating out of your hands after that, figuratively and literally! :)

Zz.

Fake Photos Alter Real Memories

Our minds can play tricks on us. That is why anecdotal evidence is not the same as scientific evidence. The process of science tries to ensure that the evidence is valid and not simply something fleeting that fools our mind.

Over the years, there have been many evidence on how our mind can play tricks on us, to the extent that we truly believe something actually happened, when in effect, it did not. At the very least, our view of "facts" can actually be altered simply by external stimuli. This is what has been shown to occur in this latest research. A number of subjects have been shown faked photos of famous public events, and these photos can actually alter the perception of the subjects who viewed them.

The original Tiananmen Square image was altered to show a crowd watching at the sidelines as a lone man stands in front of a row of tanks. The Rome anti-war protest photograph was altered to show riot police and a menacing, masked protester among the crowd of demonstrators.

When answering questions about the events, the participants had differing recollections of what happened. Those who viewed the altered images of the Rome protest recalled the demonstration as violent and negative and recollected more physical confrontation and property damage than actually occurred.

Participants who viewed the doctored photos also said they were less inclined to take part in future protests....


Scientific methodology is designed to ensure that we're not seeing something that is influenced by how our mind can play tricks on us, or how things can influence on the evidence itself. That is why a scientific evidence is more RIGOROUS than an anecdotal one.

The full reference for this work is listed below:

Dario L. M. Sacchi et al., Applied Cognitive Psychology v.21, p.1005 (2007).

Zz.

Sunday, November 25, 2007

Researchers End Debate Over Fractal Analysis Of Authentication Of Pollock's Art

I mentioned the controversy surrounding this fractal authentication of Jackson Pollock's paintings about a year ago. And now, a year later, it appears that this issue has been resolved. The fractal method isn't reliable and has failed.

The university's physicists recently "put the nail in the coffin" in the debate about using fractal analysis in authenticating art as they completed a second study related to fractal analysis and Jackson Pollock's drip paintings.
.
.
"No information about artistic authenticity can be gleaned from fractal analysis," said Katherine Jones-Smith, lead author of the study.


This should put an end to this saga. Too bad that there are still paintings that are still under dispute.

The preprint for this work can be found here.

Zz.

Saturday, November 24, 2007

The Physics of Shamu

Hey, if you have gone to Seaworld parks, and have seen the Shamu show, this article on the physics of Shamu might interest you.

I need to time my jumps perfectly in order to get the greatest amount of lift. Right before Shamu’s forward and upward momentum peaks, I flex my knees a bit and spring forward. Flying through the air feels free and effortless. Heading toward the water’s surface, my inertia is about to be halted rather abruptly. An object in motion tends to stay in motion, with the same speed and direction, unless acted upon by an unbalanced force. I aspire to a perfect arch before plunging into the water. That isn’t always the case, however. Belly flops, windmills (picture arms flailing) and back slaps are part of any Shamu trainer’s experience. The law of inertia is all too evident as I hit the water. Shamu, it seems, does not experience the same phenomenon.

The laws of physics are very evident in killer whales, to be sure.
Energy. Force. Magnitude.


I just wish that the author didn't write about Newton being "the father of modern physics". That's a bit misleading since "modern physics" is normally associated with quantum physics and special/general relativity.

Zz.

Thursday, November 22, 2007

'Cooper Pairs' Can Be Found In Insulators As Well Superconductors

This is a rather fascinating report. A team from Brown University has found evidence that Cooper Pairs can exist not just in a superconductor, but also in an insulator.

“Our finding is quite counterintuitive,” said James Valles, a Brown professor of physics who led the research. “Cooper pairing is not only responsible for conducting electricity with zero resis-tance, but it can also be responsible for blocking the flow of electricity altogether.”


However, unlike a superconductor, these Cooper pairs do not condense into a coherent state and, therefore, do not conductor electricity. It is interesting to note that this is similar to the behavior of the high-Tc cuprates in the pseudogap state. This is where one obtains a paring of the charge carriers ABOVE Tc. Here, no long-range coherence occurs even though pairing has occurred. Whether these paired carriers are precursor to superconductivity as the material goes below Tc, or are competing with superconductivity, is still a question yet to be answered.

Also interesting to note that this isn't the only situation where paring, and even superconductivity, can occur in an insulator. When an insulator shares a common surface with a superconductor, there is something call the proximity effect, whereby the superconducting wavefunction "leaks" into the insulator over some length (of the order of the the coherence length). What is different in this new work is that this pairing occurs on stand-alone insulator.

The exact citation to this work is:

M. D. Stewart, Jr. et al., Science v.318, p.1273 (2007).

Zz.

Wednesday, November 21, 2007

Educators Tout Benefits of 'Physics First' Program

I've always of the opinion that physics should be the first science subject that is taught to students. Nobel laureate Leon Lederman is a major advocate for this effort with his Project Arise. There are a lot more things around us that are clear example of physics in action.

It seems that this policy has been implemented in several schools, where physics is being taught at the high school freshman level. From all indication, this seems to have a rather positive effect in the students as they progressed through their education.

Zz.

Tuesday, November 20, 2007

Hollywood Comes to CERN

.. which isn't unexpected if you're filming the movie version of Dan Brown's "Angels and Demons". After all, the book's setting in the beginning is at CERN.

They have the same cast as "The Da Vinci Code", i.e. Tom Hanks will return as the same character. But interestingly enough, the "Angels and Demons" book came out first before "The Da Vinci Code". I suppose there isn't anything from one that significantly influence the other in terms of character and story line.

Zz.

Infrared Laser Can Be Fine-Tuned To Selectively Target And destroy Lethal Microorganisms

Here's another physics research work that one can use whenever someone claims that the study of physics has no practical application.

Physicists at Arizona State University, Johns Hopkins, and the Armed Forces Radiobiology Research Institute can now selectively zap microorganisms without harming the surrounding cells.

In their paper titled 'Selective inactivation of microorganisms by near-IR femtosecond laser pulses', physicists from Arizona State University detail how their new laser technique can destroy viruses and bacteria such as AIDS without damaging human cells. Also interesting to note is its potential to help reduce the spread of hospital infections such as MRSA — more commonly referred to in the media as the "superbug" or staph infection. MRSA is called the superbug because of its resilience and its ability to survive most treatment regimens including penicillin and methicillin.


The exact reference to this work is:

K T Tsen et al., J. Phys.: Condens. Matter v.19, p.472201 (2007).

Zz.

Monday, November 19, 2007

Don't Throw Your Physics Experiment Out In The Trash!

Here's a hint: don't simply throw out your physics experiment out in the trash can! You could cause a lot of problems, such as the one that happened at the University of San Diego.


The “device” – six glass root beer bottles with rubber stoppers linked by wires – alarmed a security guard, who called authorities just before noon, fire department spokesman Maurice Luque said.

Luque said bomb investigators with the Metro Arson Strike Team took photographs of the contraption and showed them to a physics professor on campus, who confirmed it was a student experiment.


Never a dull moment... :)

Zz.

Erykah Badu Dabbling In Quantum Physics?

I'm not making this up!

Erykah Badu, for those of you who are not up-to-speed with contemporary music, is a well-respected, grammy-winning, hip-hop artist. So she isn't Britney Spears, thankyouverymuch! Still, I'm taken aback a little bit when I read in this interview that she has been dabbling in "studying" quantum physics, and that has somehow influenced her in her upcoming album.

This album is special to me because I went deep into my Hip-Hop purse to pull out some of the most creative, scientific, mathematical producers that I could find, because that’s what I was feelin’ at the time. I had been starting to dabble in the studying of quantum physics and wanting to really, I don’t know, participate in the changing of frequencies in different areas of music. And I said, “Okay, the most likely candidate would be Dilla.” So I’m searching through my Jay Dilla mixtapes and pulling things out. [Other producers include] Madlib, Kareem Riggins, 9th Wonder, Sa-Ra, my comrade Jah Born, who did “On and On,” Frequency, my production crew - that’s Rashad Smith, James Poyser, ?uestlove. Am I leaving anybody out?


I'm guessing by what she meant as studying is that she's reading pop-science books on quantum physics. That wouldn't be so bad. I just hope that she's NOT learning about it by reading books such as "The Secret" or something worse than that.

Next, I fully expect to hear that Mariah Carey is studying Special Relativity.

:)

Zz.

Physics Phun Night

I highlighted Purdue's yearly Physics Open House event earlier. Not to be left out is the yearly University of Arizona Physics Phun Night.

Held in the Physics and Atmospheric Sciences building, the event was sponsored by the physics department and was geared toward children and families, said physics lab coordinator Larry Hoffman.


Sounds like the visitors had a lot of fun at some of the demos they were showing.

Zz.

The Physics of Turkey

Hey, why not? :)

This Thursday is a major holiday here in the US - Thanksgiving. The traditional meal involves a turkey, usually a whole turkey roasted in the oven (although deep-fried turkey is catching up there). So just in time for the holidays, we have the physics of turkey-cooking. It's your opportunity to learn or brush up on your thermodynamics.

:)

Zz.

Sunday, November 18, 2007

Purdue's Physics Open House

Purdue University Physics Dept. threw another of these Physics fest this year (I reported the one from last year).

I'll say it again here. This is such a good idea. Major universities should do this often. Not only are you introducing the general public to science, you are also opening your school up to the neighborhood so that they learn what exactly it is that you do. Often, universities and the surrounding communities don't talk often, and that can create tension between the school and people who live there. Having events like this opens up the school for local visitors, especially if it is a state school that is funded by taxpayers.

Zz.

Saturday, November 17, 2007

The Emergence of Science Cafe

I didn't know that this is getting to be as popular as being reported here. It seems that throughout the country, small cafes and bars are having "meetings" on science that are getting to be quite an event.

Science groups for young professionals who don’t wear white coats, like the year-old Secret Science Club at Union Hall, are cropping up in bars and bookstores all over the country, from Massachusetts to Montana.

“If you have a certain type of job, after a while that part of your brain starts to deteriorate,” said Amy Lee, 25, who works at an Internet startup and was attending her second Secret Science Club meeting. “You want to use it again. Plus, there’s alcohol.”


Ah!!! So that's the secret! :)

It does make sense, and it's different.

Zz.

Friday, November 16, 2007

The Adventures of the Flying Spaghetti Monster

Sometime, I'm thoroughly amazed (not to mention, highly amused) at the things that a physics student can get into. I will admit that I wasn't aware of the existence of the Flying Spaghetti Monster till I read this news report. However, it appears that the creation of one physics student at the Oregon State University by the name of Bobby Henderson will now be the subject of a discussion at the upcoming American Academy of Religion annual meeting.

You have got to read the news article to get up to speed here. It's too hilarious and, I would say, an effective means to illustrate the absurdity of forcing Intelligent Design into a science class.

So, whether you intentionally planned this or not, well done Bobby!

Zz.

Thursday, November 15, 2007

"Violating" Einstein's Photoelectric Effect

One of the most spectacular theoretical description that Einstein had ever produced is the corpuscular nature of light that he used in his 1905 photoelectric effect paper. In fact, there have been arguments put forth that of all of his 1905 papers, the one proposing this model for light is what is truly most revolutionary, even more than his special relativity theory.

In case you need a refresher, the photoelectric effect experiment is where you shine light onto a surface of a material (typically a metal). If the light has a sufficient "energy", then photoelectrons are emitted. What was puzzling before the 1900s was that light, as understood as a wave via the Maxwell Equations, seemed to not be behaving the way it should within this photoelectric effect experiment. The energy of the light wave was tied to its intensity - the larger the intensity, the larger the energy. Yet, in the photoelectric effect experiment, there were two puzzling observations:

1. As one increases the intensity, the energy distribution of the emitted photoelectrons does not change. Electrons are not emitted with more energy. Rather, increasing the intensity simply increases the number of electrons being emitted. The energy distribution remains the same as before.

2. If the frequency of the light is below some value, then no matter how intense the light is, no electrons is emitted.

Einstein took those two puzzling observations and reformulated the light description, tying the frequency, not the intensity, to the energy of light. Not only that, he proposed that light's energy comes in discrete quantum (photon). He then proposed a simple description of the photoelectric effect experiment:

KE = hf - F

where KE is the kinetic energy of the emitted photoelectrons, hf is the energy of each photon (f is the frequency of light and h is the Planck constant), while F is what is known as the work function of the material. When the photoelectric effect is defined this way, then a natural explanation for both #1 and #2 is obtained. Since light's energy only depends on the frequency, increasing the intensity does nothing to the energy of each photon. The intensity only affects the rate of photons being emitted, thus that explains why we obtain more photoelectrons, but with the same energy distribution. And if the frequency of light is less than the work function F, then no matter how high the intensity is, it is still less than F and therefore unable to produce any photoelectrons.

This photoelectric effect description was soon experimentally verified by Millikan (who initially was very skeptical of Einstein's description, but later on admitted that all of the experiments seemed to point to its validity). Since then, Einstein's formulation of what light is has certainly been verified and accepted many times over, and is the only description of light being used in many advanced application such as photoemission spectroscopy.

Still, does this mean that we do not have any evidence that this description can be "violated"? I'm putting "violated" in quotes because, as I'll explain later on, it turns out that, as is the case in many areas of physics, the photoelectric effect description of Einstein is only the simplest, most naive description of a "single-photon" emission. What this implies is that we have several situation where the Einstein's photoelectric effect equation can be "violated".

There are two different types of experiments where this can be done.

A. The Schottky effect type experiment.

This type of experiment was done[1] even way back in the 20th century, even by giants in physics such Ernest Lawrence[2]. This is where the same photoelectric effect experiment was done, but in a rather high external accelerating electric field. This field is applied usually perpendicular to the metal's surface in the direction that will accelerate the emitted electrons away from the metal's surface. What is observed here is that one can in fact observe emission of electrons even when the energy of the photons is LESS than the work function (violation of #2 above). What is going on here is that the applied electric field acts in such a way that it lowers the effective work function of the metal. The photons with a lower energy can start to emit electrons even below the metal's bulk work function.

B. Multiphoton photoemission.

This discovery occurs especially after lasers were invented, and high intensity monochromatic light sources become easily available. What is observed in these experiments is that, even without applying any high fields to the metal (i.e. no lowering of the effective work function), one can still get photoelectrons even using photons with energy lower than the work function, especially when one increases the intensity of the light source by a lot. This again violates #2. A very simple explanation for this is that, with highly intense light source such as those coming from a laser, one can induce a multiphoton photoemission process.[3,4] This is where the first photon excites an electron in the metal's conduction band to an intermediate state. Normally, its lifetime in the femtosecond range would cause it to decay back down. But with a highly intense light source, the probability of another photon being absorbed by that excited electron before it decays becomes significant. Thus, if you have a light source with photon energy just slightly more than half of the work function, there is a non-negligible probability that you can now have an emission of electron due to the absorption of 2 photons. One can easily imagine this being done for 3, 4, etc.. photons. Of course, the probability of emission with higher number of photons is significantly lower.

So here, I've just described two different ways of violating Einstein's photoelectric effect description[5]. So does this mean that we should try to get the Nobel committee to revoke Einstein's prize? Does this mean that the photoelectric effect description is no longer valid?

NO!

The most significant consequence of Einstein's photoelectric effect description - the photon - is STILL valid and very much alive. In fact, the multiphoton experiments could not be easily explained without using the concept of photons. What we know now is that the Einstein's description is valid only for the simplest case - an emission of electron using single photons only, i.e. single-photon photoemission and under a revised definition of the work function being the EFFECTIVE work function, rather than the original bulk work function. As with other aspects of physics, we make progress in the study of an area, and now we know more of what we didn't know then. Einstein's work opened the pathways to viewing light in a different way. Without such insight, most of what we know now in this area would not have been possible. Just as Newtonian mechanics became more of an approximation (albeit a valid one at our normal scales), the Einstein's equation also became more of a special case valid for the simplest situation.

Zz.

[1] E. Guth and C.J. Mullin, Phys. Rev. v.59, p.867 (1941).
[2] E.O. Lawrence and L.b. Linford, Phys. Rev. v.36, p.482 (1930).
[3] K. Giesen et al., Phys. Rev. Lett. v.55, p.300 (1985).
[4] W.S. Fann et al., Phys. Rev. B v.44, p.10980 (1991).
[5] There is actually another way, via heating the metal. See, for example, R.H. Fowler, Phys. Rev. v.38, p.45 (1931).