Physics Discussion Thread

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Sanjay M
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Re: Physics Thread.

Postby Sanjay M » 08 Mar 2009 13:55

I watched the Kepler launch live on the net, the other night.

Here are some videos about the Kepler mission:

http://www.youtube.com/watch?v=MjSJhgQXH48

http://www.youtube.com/watch?v=VVnL851PJuU

http://www.youtube.com/watch?v=Oqy1mtdba7M


I think that planet-finding is becoming the new Astronomy2.0, whereby a whole new level of detail is being revealed about the myriad of stars dotting the sky.

My personal opinion is that the laws of statistics must prevail. Given that over 300 exoplanets have been uncovered in such a short period of time (last 14 years), then planetary systems seem to be fairly common in our galaxy. Therefore statistical probabilities would dictate that out of such a huge number of stars, then even a small fraction of them having Earth-like qualities would add upto quite a lot.

Of course, the vast distances separating inhabited star systems would make detection of one another extremely unlikely. Consider that mankind has only been using radio communication for less than a century. Such signals would hardly have traveled 100 light years radial distance from our planet/sun, and even then their signal strength would be ridiculously weakened that far out.

Perhaps it's best that we not be found by others first, before we find them. Because if some more technically advanced civilization had the means to get here, how do we know they would treat us peacefully? As past experience has shown us, adventurous peoples often venture to far shores for profit and exploitation, which can lead to colonization and subjugation of the less advanced people.

If someone else liked our uniquely inhabitable biosphere, they might strip us out of it as the dominant species, in order to more securely make use of it for themselves.

Sanjay M
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Re: Physics Thread.

Postby Sanjay M » 08 Mar 2009 14:38

Regarding the viewing of transits, yes, the planetary orbital plane of the star system in question has to be aligned with line of sight of Kepler's telescope. This is about 1/200 odds (I'm assuming that the directional orientation of planetary orbital planes are completely random and uncorrelated to each other.)

But again, with a sample size of hundreds of thousands of stars or even millions, then naturally even 1/200 odds will yield a significant number of transit events.
Out of those, the transits occurring at approximately 1-year interval separations around G-class stars (having sun-like spectral emissions), would be the targets of interest.

These targets would then be subjected to more detailed examination from Earth-based and space-based telescopes of present and future.

Sanjay M
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Re: Physics Thread.

Postby Sanjay M » 08 Mar 2009 15:01

Some scientists, like the reknowned French astronomer, Antoine Labeyrie, are working on designs for telescopes capable of literally imaging the surface of Earth-like planets tens of light-years away. Labeyrie's Exo-Earth Imager is considered to be the most advanced telescope conceived:

http://www.space.com/scienceastronomy/a ... mager.html

There are of course fundamental physical limitations to being able to see so far, and in such detail:

http://www.astronomycafe.net/anthol/remote.html

Amber G.
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Re: Physics Thread.

Postby Amber G. » 10 Mar 2009 02:24

Few random comments:

Such signals would hardly have traveled 100 light years radial distance from our planet/sun, and even then their signal strength would be ridiculously weakened that far out.


True, the radio signals would weaken over vast distances, but to put the things in perspective, two good radio telescopes could detect/analyze the signals even if they are located in two opposite corners of our galaxy (that is if galaxies have ‘corners’ :) - , I mean here, even thousands of light years away) (Rough calculation, assuming a 50 m antenna on both sides and 500 MW power – the range using reasonable S/N ratio for the current available technology etc, would be, again assuming my calculations are correct, of the order of about 5000 light years )

BTW as most of people already know here of project SETI, where due to lot of potential sources, there is lot of data in the form of radio signals to analyze You can help the SETI search at home using your own PC to analyze the recorded signals - which are mostly just random noise .. (of course, an intelligent signal also, at first, will look like a random noise)

In some way, it is too late if you don’t want others to find out.. not only episodes of “sas bhi kabhi bahi thi”.. there are targeted signals (using mathematical language etc) sent to many of our neighbors in last 10 years or so. (For example, see wiki or other articles about CETI)

About viewing transits, the odds are nearly 100% that the transit would be in right “orientation”. Most of the starts (and their planets orbits) in our galaxy, lie in the galactic plane. To put the things in perspective, again.. if one watches our sun from, say Vega (or any other ordinary star) *all* planets would have a transit … (for earth, every year, the transit would last for a little more than a day). Even if one assumes a total random plane for orbits.. the odds would be pretty high (say, 70 % or more) that one would be able to see the transit, not too far from “equator” of sun to observe it and to get meaningful data (assuming, of course, other conditions to observe a transit are there)

As said before, "orientation" is not really a significant figure which lowers the odds .. number of planets, radius of orbit. size of the star (wrt to the size orbit of planet) .. and timing is more significant..

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Re: Physics Thread.

Postby Arya Sumantra » 10 Mar 2009 02:31

Amber G. wrote:BTW as most of people already know here of project SETI, where due to lot of potential sources, there is lot of data in the form of radio signals to analyze You can help the SETI search at home using your own PC to analyze the recorded signals - which are mostly just random noise.


Did that on university desktop. I did it only because the graphic countour plot looked really cool. It slowed down my pc and internet like anything. When the pc was idle in my absence the passers by who didn't know about SETI really thought I was doing something whacky with the data.

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Re: Physics Thread.

Postby Amber G. » 10 Mar 2009 06:52

Just a small point, I talked about "orientation" etc.. just to clear up point(s), raised by say ...
Sanjay M wrote:Regarding the viewing of transits, yes, the planetary orbital plane of the star system in question has to be aligned with line of sight of Kepler's telescope. This is about 1/200 odds (I'm assuming that the directional orientation of planetary orbital planes are completely random and uncorrelated to each other.).


I don't know exactly how one gets 1/200 number form "Randomness of directional orientation" .. but the figure happens to be quite correct for earth/sun system (ratio of radius of sun to radius of obit of earth) ... the ratio would be a little less for say Jupitor, and a little higher for Venus.

Hope ths helps.

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Re: Physics Thread.

Postby vina » 10 Mar 2009 09:48

Cross posting.. A bit OT, but nevertheless relevant.

Yaawnn.. For smart aleck Fyzzicists like Bade Saar and other stat /math/ science types. Atleast now folks know whom to throw mud at. It is not the Milan & Sangam and boor YumBeeYeas, but the Fyzzicists and Science types.

The New York Times
March 10, 2009
They Tried to Outsmart Wall Street
By DENNIS OVERBYE

Emanuel Derman expected to feel a letdown when he left particle physics for a job on Wall Street in 1985.

After all, for almost 20 years, as a graduate student at Columbia and a postdoctoral fellow at institutions like Oxford and the University of Colorado, he had been a spear carrier in the quest to unify the forces of nature and establish the elusive and Einsteinian “theory of everything,” hobnobbing with Nobel laureates and other distinguished thinkers. How could managing money compare?

But the letdown never happened. Instead he fell in love with a corner of finance that dealt with stock options.

“Options theory is kind of deep in some way. It was very elegant; it had the quality of physics,” :rotfl: :rotfl: Dr. Derman explained recently with a tinge of wistfulness, sitting in his office at Columbia, where he is now a professor of finance and a risk management consultant with Prisma Capital Partners.

Dr. Derman, who spent 17 years at Goldman Sachs and became managing director, was a forerunner of the many physicists and other scientists who have flooded Wall Street in recent years, moving from a world in which a discrepancy of a few percentage points in a measurement can mean a Nobel Prize or unending mockery to a world in which a few percent one way can land you in jail and a few percent the other way can win you your own private Caribbean island.

They are known as “quants” because they do quantitative finance. Seduced by a vision of mathematical elegance underlying some of the messiest of human activities, they apply skills they once hoped to use to untangle string theory or the nervous system to making money.

This flood seems to be continuing, unabated by the ongoing economic collapse in this country and abroad. Last fall students filled a giant classroom at M.I.T. to overflowing for an evening workshop called “So You Want to Be a Quant.” Some quants analyze the stock market. Others churn out the computer models that analyze otherwise unmeasurable risks and profits of arcane deals, or run their own hedge funds and sift through vast universes of data for the slight disparities that can give them an edge.

Still others have opened an academic front, using complexity theory or artificial intelligence to better understand the behavior of humans in markets. In December the physics Web site arXiv.org, where physicists post their papers, added a section for papers on finance. Submissions on subjects like “the superstatistics of labor productivity” and “stochastic volatility models” have been streaming in.

Quants occupy a revealing niche in modern capitalism. They make a lot of money but not as much as the traders who tease them and treat them like geeks (that part is very true). Until recently they rarely made partner at places like Goldman Sachs. In some quarters they get blamed for the current breakdown — “All I can say is, beware of geeks bearing formulas,” Warren Buffett said on “The Charlie Rose Show” last fall. Even the quants tend to agree that what they do is not quite science.

As Dr. Derman put it in his book “My Life as a Quant: Reflections on Physics and Finance,” “In physics there may one day be a Theory of Everything; in finance and the social sciences, you’re lucky if there is a useable theory of anything.”

Asked to compare her work to physics, one quant, who requested anonymity because her company had not given her permission to talk to reporters, termed the market “a wild beast” that cannot be controlled, and then added: “It’s not like building a bridge. If you’re right more than half the time you’re winning the game.” There are a thousand physicists on Wall Street, she estimated, and many, she said, talk nostalgically about science. “They sold their souls to the devil,” she said, adding, “I haven’t met many quants who said they were in finance because they were in love with finance.”

The Physics of Money

Physicists began to follow the jobs from academia to Wall Street in the late 1970s, when the post-Sputnik boom in science spending had tapered off and the college teaching ranks had been filled with graduates from the 1960s. The result, as Dr. Derman said, was a pipeline with no jobs at the end. Things got even worse after the cold war ended and Congress canceled the Superconducting Supercollider, which would have been the world’s biggest particle accelerator, in 1993.

They arrived on Wall Street in the midst of a financial revolution. Among other things, galloping inflation had made finances more complicated and risky, and it required increasingly sophisticated mathematical expertise to parse even simple investments like bonds. Enter the quant.

“Bonds have a price and a stream of payments — a lot of numbers,” said Dr. Derman, whose first job was to write a computer program to calculate the prices of bond options. The first time he tried to show it off, the screen froze, but his boss was fascinated anyway by the graphical user interface, a novelty on Wall Street at the time.

Stock options, however, were where this revolution was to have its greatest, and paradigmatic, success. In the 1970s the late Fischer Black of Goldman Sachs, Myron S. Scholes of Stanford and Robert C. Merton of Harvard had figured out how to price and hedge these options in a way that seemed to guarantee profits. The so-called Black-Scholes model has been the quants’ gold standard ever since.
(the Black Scholes has a whole list of assumptions behind it, that would make even a JNU /DSE/ISI ding dong blush)
In the old days, Dr. Derman explained, if you thought a stock was going to go up, an option was a good deal. But with Black-Scholes, it doesn’t matter where the stock is going. Assuming that the price of the stock fluctuates randomly from day to day, the model provides a prescription for you to still win by buying and selling the underlying stock and its bonds.

“If you’re a trading desk,” Dr. Derman explained, “you don’t care if it goes up or down; you still have a recipe.”

The Black-Scholes equation resembles the kinds of differential equations physicists use to represent heat diffusion and other random processes in nature. Except, instead of molecules or atoms bouncing around randomly, it is the price of the underlying stock. (I had already slammed this rubbish in BR. Of course it will resemble the heat equation idiots, because you assumed at a molecular level that stock prices have exactly the same properties as Brownian motion, which is the mathematical model for heat )

The price of a stock option, Dr. Derman explained, can be interpreted as a prediction by the market about how much bounce, or volatility, stock prices will have in the future.

But it gets more complicated than that. For example, markets are not perfectly efficient — prices do not always adjust to right level and people are not perfectly rational. Indeed, Dr. Derman said, the idea of a “right level” is “a bit of a fiction.” As a result, prices do not fluctuate according to Brownian motion. Rather, he said: “Markets tend to drift upward or cascade down. You get slow rises and dramatic falls.” (ah, after trillions of losses, Fyzzicists realize this , not much diff between ISI/JNU ding dongs and Ivy league Fyzzicists aye ?)

One consequence of this is something called the “volatility smile,” in which options that benefit from market drops cost more than options that benefit from market rises.

Another consequence is that when you need financial models the most — on days like Black Monday in 1987 when the Dow dropped 20 percent — they might break down :rotfl: :rotfl: . The risks of relying on simple models are heightened by investors’ desire to increase their leverage by playing with borrowed money. In that case one bad bet can doom a hedge fund. Dr. Merton and Dr. Scholes won the Nobel in economic science in 1997 for the stock options model. Only a year later Long Term Capital Management, a highly leveraged hedge fund whose directors included the two Nobelists, collapsed and had to be bailed out to the tune of $3.65 billion by a group of banks.

Afterward, a Merrill Lynch memorandum noted that the financial models “may provide a greater sense of security than warranted; therefore reliance on these models should be limited.”

That was a lesson apparently not learned.

Respect for Nerds

Given the state of the world, you might ask whether quants have any idea at all what they are doing.

Comparing quants to the scientists who had built the atomic bomb and therefore had a duty to warn the world of its dangers, a group of Wall Streeters and academics, led by Mike Brown, a former chairman of Nasdaq and chief financial officer of Microsoft, published a critique of modern finance on the Web site Edge.org last fall calling on scientists to reinvent economics. (most of 'em two left legged critters cant find their asses with their two hands beyond their narrow fields of expertise. Talk about "reinventing" anything !)

Lee Smolin, a physicist at the Perimeter Institute for Theoretical Physics in Waterloo, Ontario, who was one of the authors, said, “What is amazing to me as I learn about this is how flimsy was the theoretical basis of the claims that derivatives and other complex financial instruments reduced risk, when their use in fact brought on instabilities.”

But it is not so easy to get new ideas into the economic literature, many quants complain. J. Doyne Farmer, a physicist and professor at the Santa Fe Institute, and the founder and former chief scientist of the Prediction Company, said he was shocked when he started reading finance literature at how backward it was, comparing it to Middle-Ages theories of fire. “They were talking about phlogiston — not the right metaphor,” Dr. Farmer said.

One of the most outspoken critics is Nassim Nicholas Taleb, a former trader and now a professor at New York University. He got a rock-star reception at the World Economic Forum in Davos this winter. In his best-selling book “The Black Swan” (Random House, 2007), Dr. Taleb, who made a fortune trading currency on Black Monday, argues that finance and history are dominated by rare and unpredictable events.

“Every trader will tell you that every risk manager is a fraud,” he said, and options traders used to get along fine before Black-Scholes. “We never had any respect for nerds.”

Dr. Taleb has waged war against one element of modern economics in particular: the assumption that price fluctuations follow the familiar bell curve that describes, say, IQ scores or heights in a population, with a mean change and increasingly rare chances of larger or smaller ones, according to so-called Gaussian statistics named for the German mathematician Friedrich Gauss. (oops.. dont tell that to the social "sciences" monkeys in JNU , ISI and other ding dong places, you could get lynched)

But many systems in nature, and finance, appear to be better described by the fractal statistics popularized by Benoit Mandelbrot of IBM, which look the same at every scale. An example is the 80-20 rule that 20 percent of the people do 80 percent of the work, or have 80 percent of the money. Within the blessed 20 percent the same rule applies, and so on. As a result the odds of game-changing outliers like Bill Gates’s fortune or a Black Monday are actually much greater than the quant models predict, rendering quants useless or even dangerous, Dr. Taleb said.

“I think physicists should go back to the physics department and leave Wall Street alone,” he said.
:rotfl: :rotfl: :rotfl: . Perfect

When Dr. Taleb asked someone to come up and debate him at a meeting of risk managers in Boston not too long ago, all he got was silence. Recalling the moment, Dr. Taleb grumbled, “Nobody will argue with me.”

Dr. Derman, who likes to say it is the models that are simple, not the world, maintains they can be a useful guide to thinking as long as you do not confuse them with real science — an approach Dr. Taleb scorned as “schizophrenic.”

Dr. Derman said, “Nobody ever took these models as playing chess with God.”

Do some people take the models too seriously? “Not the smart people,” he said.
(the lyin sonofabitch . In India , "experts"/ statisticicans, "economists" and other charlatans sold the modeling rubbish for 40 years and ruined everyone's happiness. And oh, they did play god with the command economy rubbish)

Quants say that they should not be blamed for the actions of traders. :rotfl: :rotfl: They say they have been in the forefront of pointing out the models’ shortcomings.

“I regard quants to be the good guys,” said Eric R. Weinstein, a mathematical physicist (oh, yeah. being so objective aren't we , when we cover the ass*s of our own kind)who helps run the Natron Group, a hedge fund in Manhattan. “We did try to warn people,” he said. “This is a crisis caused by business decisions. This isn’t the result of pointy-headed guys from fancy schools who didn’t understand volatility or correlation.” (of course it was you lyin sack sh*t)

Nigel Goldenfeld, a physics professor at the University of Illinois and founder of NumeriX, which sells investment software, compared the financial meltdown to the Challenger space shuttle explosion, saying it was a failure of management and communication. (now that is seriously friggin funny and fundamentally retarded)

Prisoners of Wall Street

By their activities, quants admit that despite their misgivings they have at least given cover to some of the wilder schemes of their bosses, allowing traders to conduct business in a quasi-scientific language and take risks they did not understand.

Dr. Goldenfeld of Illinois said that when he posted scholarly articles, some of which were critical of financial models, on his company’s Web site, salespeople told him to take them down. The argument, he explained, was that “it made our company look bad to be associating with Jeremiahs saying that the models were all wrong.”

Dr. Goldenfeld took them down. In business, he explained, unlike in science, the customers are always right.

Quants, in short, are part of the system. “They get paid, a Faustian bargain everybody makes,” said Satyajit Das, a former trader and financial consultant in Australia, who likes to refer to them as “prisoners of Wall Street.”

“What do we use models for?” Mr. Das asked rhetorically. “Making money,” he answered. “That’s not what science is about.”

The recent debacle has only increased the hunger for scientists on Wall Street, according to Andrew Lo, an M.I.T. professor of financial engineering who organized the workshop there, with a panel of veteran quants.

The problem is not that there are too many physicists on Wall Street, he said, but that there are not enough :rotfl: :rotfl: . A graduate, he told the young recruits, can make $75,000 to $250,000 a year as a quant but can also be fired if things go sour. He said an investment banker had told him that Wall Street was not looking for Ph.D.’s, but what he called “P.S.D.s — poor, smart and a deep desire to get rich.”

He ended his presentation with a joke that has been told around M.I.T. for a long time, but seemed newly relevant; “What do you call a nerd in 10 years? Boss.”

An earlier version of this article misspelled the given name of Satyajit Das.

Sanjay M
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Re: Physics Thread.

Postby Sanjay M » 10 Mar 2009 18:38

Clearly, the randomness of directional orientation of the planetary orbital plane is what maintains uniform odds of viewing a transit within our line of sight.

From what I've read, planetary orbital planes are not lined up with the galactic plane of rotation. This is what enables us to use the gravitation wobble method for exoplanet detection. After all, to see a gravitation wobble, the planetary orbital plane of the remote system would have to be normal to our line of sight. Star systems whose planetary orbits can be examined by transit method cannot be similarly examined by wobble method, and vice-versa.

So transit detection and wobble detection are 2 mutually exclusive methods, which are each useful given the diversity of planetary orbital plane orientations among the visible stars.

But of course, wobble method is less suitable for finding something as small as an Earth-like planet, which is too bad.

Other interesting new methods will be coronograph or masking of stellar light. Interferometry could likely be the most powerful technique.

I'm wondering if neutrino detectors might also be useful.

Speaking of which, they say that there will be some breakthroughs in finally determining the nature of Dark Matter within the next few years. This and the detection of the Higgs Boson will be big stories to watch out for.

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Re: Physics Thread.

Postby Amber G. » 15 Mar 2009 01:37

Higgs Boson in News
The Higgs particle, the last piece of the Standard Model of particle physics menagerie that has yet to be observed, is running out of places to hide—if, that is, it exists at all. Fermi National Accelerator Laboratory in Batavia, Ill., today narrowed the range of mass where the Higgs might be found.

The Higgs boson, named for British physicist Peter Higgs, is believed to give other elementary particles, such as the heavy W and Z bosons, their mass, so finding it or proving it does not exist would have major implications in ground-up interpretations of how the world works.

"This is a very interesting time in particle physics, because we have this Standard Model, which explains everything we've observed and everything we know about for the last 30 years with no significant deviations. And, yet, we know that the Standard Model can't be the whole story of nature," says John S. Conway, a physicist at the University of California, Davis, and a member of the Collider Detector at Fermilab (CDF) collaboration, one of two teams involved in the new mass-range results. Many of the lingering questions in physics could be answered or at least clarified when the model's missing piece is located. "Whatever we discover," Conway adds, "it's going to be astounding."

Previous collider experiments had placed a lower bound of 114 giga-electron volts (GeV), a measure that can be used for particle mass, on the Higgs, and theoretical calculations require it to be less than 185 GeV. The new Fermilab results, from its Tevatron collider, rule out a Higgs mass between 160 and 170 GeV. (All of these constraints are at the 95 percent confidence level, according to Fermilab.)

Collider experiments such as those at the Tevatron smash particles together at extremely high energies and observe what is produced, including some exotic but short-lived particles. "We look for the signature of things we know are there and things we think might be there, like the Higgs," says physicist Craig Blocker of Brandeis University in Waltham, Mass., also a member of the CDF team. "If the Higgs had a mass in this fairly narrow range" of 160 to 170 GeV, he says, "we should have seen it, we had a good chance to see it."

Conway says the extension of the excluded Higgs masses at Fermilab is "a really exciting development." All the same, he thinks the Higgs, if it is to be found, will be first seen at the more powerful Large Hadron Collider (LHC) near Geneva, Switzerland, which is slated to come back online later this year after an aborted start-up last September. (Both Conway and Blocker are also working on physics projects at the LHC.) "It is a bit of a race" to find the Higgs, Conway says, "but if I had to bet money, I would bet on the LHC."

There are some scenarios, however, in which Fermilab—enjoying its continuing status as particle physics top dog while the LHC is sidelined—might win that race. If the Higgs happened to have a mass around 150 GeV, which Conway believes is unlikely—evidence points to a lighter particle in the neighborhood of 120 GeV, he says—the Tevatron could find it relatively soon. Alternately, with more time to gather data, the Tevatron could close in even tighter on the Higgs by inching its lower mass bound upward.

But what if the entire mass window were exhausted—if experiments showed that the Higgs, or something like it, didn't exist at all? "That would basically mean we have a very deep and fundamental lack of understanding of what is going on in the Standard Model," Blocker says. "If there's not something like the Higgs or something similar giving masses to the W and Z, we have no clue as to how that's happening."

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Re: Physics Thread.

Postby Sanjay M » 15 Mar 2009 02:59

Yes, Fermilab's Tevatron is likely to detect the Higgs first after all, if it even exists. So far they've managed to rule out certain energy zones, thus narrowing down the field of search for it.

The LHC will be able to more accurately characterize the nature of the Higgs boson afterwards, which will also be good.

Physicists have also proposed the idea of Muon-colliders which could act as "Higgs factories" producing the particle in tremendous quantities on demand.

Nobody seems to have any practical applications for Higgs bosons though, beyond merely validating their existence as the last major puzzle of theoretical physics.

Maybe it will be upto 22nd Century physicists to find a practical use for the Higgs boson.

I've always wondered if generating an artificial Higgs field could somehow be used to defy the limits of gravity, inertia and even the speed of light.
For instance, does the Higgs have an anti-particle? Based on existing theories of symmetry, it should. Would such anti-particles be able to counter existing effects of the Higgs field?

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Re: Physics Thread.

Postby Sanjay M » 24 Mar 2009 18:41

Berkeley's Raymond Chiao has some interesting conjecture on gravity waves:

http://www.technologyreview.com/blog/arxiv/23198/

According to him, it should be possible for a superconductor to reflect gravity waves like a mirror.

This then leads to all sorts of interesting possibilities, such as the idea of vibrating a superconducting sheet at a high enough frequency to produce a standing wave that could be of sufficient magnitude to offset gravity.

It's just a theory of course, but Chaio has found some interesting data from NASA's Gravity Probe B to corroborate his work.

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Re: Physics Thread.

Postby Tanaji » 09 Apr 2009 13:43

Can any one suggest a good book on basic school level planetary motion? Something that builds up your concepts on how and why planets and constellations move, the effect on earth, why seasons are caused etc. This is to understand the underlying theory for getting into astronomy...

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Re: Physics Thread.

Postby Sanjay M » 10 Apr 2009 10:01

One astronomy forum I like to hang out in is the Bad Astronomy and Universe Today Forum

They have a broad mix of participants, from the highly knowledgeable to the curious absolute novices.

They can probably recommend the best texts and so on. They also answer all kinds of questions in the forum.
One of their founders, Phil Plait, has even produced a marvelous series of videos on Youtube, which you can look up by searching for "Bad Astronomy".

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Re: Physics Thread.

Postby Viv Sreenivasan » 10 Apr 2009 19:10

This is a nice webiste with regards to the phenemenon of global warming, its gives an intersting animation showing the warming that has already occurred over the subcontinent. Global warming imo is going to have a detrimental impact on various aspects of life in India in the future. More heat related deaths, increasing deficiency of vitamin D etc. India needs to invest in renewables like nuclear and wind heavily.

http://data.giss.nasa.gov/gistemp/

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Re: Physics Thread.

Postby Rahul M » 10 Apr 2009 19:26

^^^
unfortunately we will not the face the problems of our own emissions alone but that of others too. unitary emission cuts is not going to help much.

p.s. for this kind of topic please use the nature and environment thread.

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Re: Physics Thread.

Postby Viv Sreenivasan » 22 Apr 2009 10:22

Interesting. Seem the Sun is going into a mauder minimmum, last time this happened in the 17th century, there was an Ice Age. Hopefully this will happen again. India needs cooling down by a few degrees. :D

'Still Sun' baffling astronomers

The Sun is the dimmest it has been for nearly a century.

There are no sunspots, very few solar flares - and our nearest star is the quietest it has been for a very long time.

The observations are baffling astronomers, who are due to study new pictures of the Sun, taken from space, at the UK National Astronomy Meeting.

The Sun normally undergoes an 11-year cycle of activity. At its peak, it has a tumultuous boiling atmosphere that spits out flares and planet-sized chunks of super-hot gas. This is followed by a calmer period.

Last year, it was expected that it would have been hotting up after a quiet spell. But instead it hit a 50-year year low in solar wind pressure, a 55-year low in radio emissions, and a 100-year low in sunspot activity.

According to Prof Louise Hara of University College London, it is unclear why this is happening or when the Sun is likely to become more active again.

"There's no sign of us coming out of it yet," she told BBC News.

"At the moment, there are scientific papers coming out suggesting that we'll be going into a normal period of activity soon.

"Others are suggesting we'll be going into another minimum period - this is a big scientific debate at the moment."


Sunspots could be seen by the Soho telescope in 2001 (l), but not this year (r)


In the mid-17th Century, a quiet spell - known as the Maunder Minimum - lasted 70 years, and led to a "mini ice-age".

This has resulted in some people suggesting that a similar cooling might offset the impact of climate change.

According to Prof Mike Lockwood of Southampton University, this view is too simplistic.

"I wish the Sun was coming to our aid but, unfortunately, the data shows that is not the case," he said.

Prof Lockwood was one of the first researchers to show that the Sun's activity has been gradually decreasing since 1985, yet overall global temperatures have continued to rise.

"If you look carefully at the observations, it's pretty clear that the underlying level of the Sun peaked at about 1985 and what we are seeing is a continuation of a downward trend (in solar activity) that's been going on for a couple of decades.

"If the Sun's dimming were to have a cooling effect, we'd have seen it by now."

'Middle ground'

Evidence from tree trunks and ice cores suggest that the Sun is calming down after an unusually high point in its activity.

Professor Lockwood believes that as well as the Sun's 11-year cycle, there is an underlying solar oscillation lasting hundreds of years.

He suggests that 1985 marked the "grand maximum" in this long-term cycle and the Maunder Minimum marked its low point.

"We are re-entering the middle ground after a period which has seen the Sun in its top 10% of activity," said Professor Lockwood.

"We would expect it to be more than a hundred years before we get down to the levels of the Maunder Minimum."

He added that the current slight dimming of the Sun is not going to reverse the rise in global temperatures caused by the burning of fossil fuels.

"What we are seeing is consistent with a global temperature rise, not that the Sun is coming to our aid."

Data from the Intergovernmental Panel on Climate Change (IPCC) shows global average temperatures have risen by about 0.7C since the beginning of the 20th Century.

And the IPCC projects that the world will continue to warm, with temperatures expected to rise between 1.8C and 4C by the end of the century.

No-one knows how the centuries-long waxing and waning of the Sun works. However, astronomers now have space telescopes studying the Sun in detail.

According to Prof Richard Harrison of the Rutherford Appleton Laboratory, Oxfordshire, this current quiet period gives astronomers a unique opportunity.

"This is very exciting because as astronomers we've never seen anything like this before in our lifetimes," he said.

"We have spacecraft up there to study the Sun in phenomenal detail. With these telescopes we can study this minimum of activity in a way that we could not have done so in the past."

http://news.bbc.co.uk/2/hi/science/nature/8008473.stm

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Re: Physics Thread.

Postby Rahul M » 01 May 2009 21:57

some forumites might be aware that ECG Sudarshan (http://en.wikipedia.org/wiki/George_Sudarshan) had some claim to the 2005 Nobel award in Physics.

here's his letter to the nobel committee.(in 2005)

brought to my attention by an email.
http://www.flonnet.com/fl2224/stories/2 ... 610200.htm
Sudarshan's letter

EXCERPTS from E.C.G. Sudarshan's letter to the Nobel Committee on the 2005 Nobel Award in Physics to Roy J. Glauber for Quantum Theory of Optical Coherence:

"In the announcement of the 2005 Physics Nobel Prize, the Swedish Royal Academy has chosen R.J. Glauber to be awarded half of the prize. The prize winners are chosen by the Royal Academy, but no one has the right to take my discoveries and formulations and ascribe them to someone else!

"The correct formulation of the quantum mechanical treatment of optics was carried out by me in my paper in 1963. In that I showed that every state can be represented in the diagonal form... This diagonal representation is valid for all fields.

"... The irony of the situation is that in spite of all these facts being available in print, the diagonal representation instead of being referred to as the Sudarshan representation is dubbed as either the P-Representation (as if Glauber discovered and named it first) or at best as `Glauber-Sudarshan' Representation.

"While the distinction of introducing coherent states as basic entities to describe optical fields certainly goes to Glauber, the possibility of using them to describe `all' optical fields (of all intensities) through the diagonal representation is certainly due to Sudarshan. Thus there is no need to `extract' the classical limit [as stated in the Nobel citation]. Sudarshan's work is not merely a mathematical formalism. It is the basic theory underlying all optical fields. All the quantum features are brought out in his diagonal representation...

"It is my belief that the Royal Swedish Academy was impartial and that to assure the proper priorities it has a Committee in Physics, with members competent to examine and understand the published work. It was also my belief that the members of the Committee did their work diligently and with care. I am therefore genuinely surprised and disappointed by this year's choice. It would distress me and many others if extra scientific considerations were responsible for this decision. It is my hope that these glaring injustices would be noted by the Academy and modify the citations.

Give unto Glauber only what is his."

Sincerely yours,
E.C.G. Sudarshan

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Re: Physics Thread.

Postby Amber G. » 02 May 2009 01:31

Rahul, WRT Glauber and Sudershan BRF had quite a few posts (including the letter you quote, a few articles from TOI, NYtimes and comments from other well known physicists) when Glauber's Noble prize was announced.
(I almost went ballistic when I heard the news about Noble prize, Glauber's name and quoted work and saw it was wrongly named.. and had a post in BRF almost right away :)

Some one reported (I think correctly) that George Sudarshan currently holds the record of the "most nominated Nobel Prize candidate alive who has yet to receive any Nobel Prize"

There was a letter signed by several prestigious physicist and sent to Noble committee. (I think they - Noble committee - later realized that they goofed badly but did not do anything as they were more interested in saving their H&D - Not to mention, Glauber fellow is politically powerful - from Harvard and all that - and is not a nice fellow. (He has shown enmity to EGC, and other Indian (and others too) physicists)


This is IMO - of course, I may be a little biased as I did not liked the Glauber fellow (had a professor who worked with him and really hated this guy) .
.
EGC, on the other hand is a close friend of family , a very generous fellow, modest to a fault and a guru in a true sense .. etc. (In fact it took quite a bit of prodding on his (EGC’s) friends part for him to speak out)

Ironic is that ECG also missed the noble prize for V-A theory of weak interaction because he did not attend the APS meeting (lack of funds) and his prof who delivered the paper but the paper did not appear in ‘official proceedings’ .. (Richard Feynman, Murray Gell-Mann work was somewhat independent but it was published later, but some how they got the sole credit in the West (although Feynman always gave credit to Sudershan..) …

Not to mention that 1979 prize given to Weinberg, Glashow and Abdus Salam was based on Sudarshan’s work and he should have been included.

Here is relevant part from wiki:
http://en.wikipedia.org/wiki/Nobel_Prize_controversies#Recent_controversial_exclusions

George Sudarshan and Robert Marshak drawn up the successful V-A (vector minus axial vector, or left-handed) theory for weak interactions first in 1957. It is essentially the same theory as that somewhat-worked-upon-later 'mathematical physics' paper, without any raw experimental data backing, on the structure of the weak interaction by Richard Feynman and Murray Gell-Mann; both briefed on the former group's results before via informal sharings earlier on[18] amongst themselves, without giving in their subsequent joint paper any formal credits due the theory's originators, except for informal allusions. Now it is popularly known in the west as the Feynman-Gell-Mann theory only.[19] The V-A theory for weak interactions was in actuality a new Law of Nature discovered. It was conceived in the face of a string of apparently contradictory experimental results, including several of Chien-Shiung Wu's, though also helped along by a sprinkling of other evidences too, e.g. the muon (discovered in 1936, it had a colorful history[20][21]itself—and would lead on again to a new revolution[22] in the 21st Century).[23] Therefore, that this breakthrough achievement was given a miss of a Nobel Award was all the more surprising . The V-A theory would later lay the foundation for the electroweak interaction theory. George Sudarshan himself regarded the V-A theory as his finest work to date. Later, it was subsumed under the electroweak interaction unification theory by Sheldon Glashow, Abdus Salam and Steven Weinberg that would go on to clinch the 1979 Nobel Prize in Physics for the 'triumvirate'. The Sudarshan-Marshak (or V-A theory) was to meet with another coda of curious fate and dubious honour later on again of being assessed, preferably and favourably—after the strangely tortuous, and, at times, 'funny' pedantic imbroglios, and it goes on and on—as "beautiful" by J. Robert Oppenheimer;[18] and, suffering a complete reversal, like a last apparent 'twist', again, as it were, was given an exactly opposite assessment as "less complete", "inelegant" by John Gribbin.[24]


Also from the same source:

The 2005 Nobel Prize In Physics controversy involved George Sudarshan's relevant work in quantum optics (1960), which was considered by many to have been slighted in this award. Roy J. Glauber—who initially derided the former theory representations and later produced the same P-representation under a different name, viz., Sudarshan-Glauber representation or Sudarshan diagonal representation—was the winner instead


And ..

For the first time, Sudarshan himself has broken his silence over the Nobel controversy. Speaking to the Hindustan Times, he expressed frustration at the way he was ignored for top science honours, saying "The 2005 Nobel prize for Physics was awarded for my work, but I wasn’t the one to get it. Each one of the discoveries that the Nobel was given for were based on my research."[3]
About having been denied the Nobel in 1979 as well, Sudarshan said, "Steven Weinberg, Sheldon Glashow and Abdus Salam built on work I had done as a 26-year-old student. If you give a prize for a building, shouldn’t the fellow who built the first floor be given the prize before those who built the second floor?"



IIRC, there was a nice write up in TOI by Prof Mehta (IITD quantum optics guy who has worked with EGC Sudershan , Marshak etc with technical details about how the credit given to Glauber was unmerited while Sudershan was left out – not something Noble committee should be proud of.

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Re: Physics Thread.

Postby negi » 02 May 2009 01:55

Hmm.. So even the purest of the pure awards are not free from bias and politics to an extent that it happened to the same guy not once but twice . :(

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Re: Physics Thread.

Postby Amber G. » 04 May 2009 23:18

Rahul, Negi - Just to add from:

From Hindu (Nov 05, 2005)
Hindu (Newspaper)

NOBEL PRIZE

Elusive recognition
R. RAMACHANDRAN
ONE half of this year's Nobel Prize in Physics is for "the contribution to the quantum theory of optical coherence". But the Nobel Committee's decision to name only Roy J. Glauber of Harvard University for this award has surprised many Indian physicists greatly. In doing so, they feel, the Nobel Committee has completely ignored the fundamental contribution of the Indian physicist E.C.G. Sudarshan to the subject on which all subsequent developments in the field of quantum optics have been based. Sudarshan is currently a professor at the University of Texas, Austin, United States.
Indeed, soon after the announcement of the prize, an Indian English-language daily ran a story quoting several Indian physicists who expressed their displeasure with the Nobel selection. But now, with Sudarshan himself raising the issue, the controversy has acquired renewed significance. He had written a letter to the editor of The New York Times (which was not published) to correct the errors in the news report of October 5 on the Nobel Prize. But, more importantly, in a strongly worded letter to the Nobel Committee, he has questioned several statements made in the information document accompanying the award to Glauber.
There is no denying that the credit for introducing the concept of a coherent state to describe light beams and their detection in quantum mechanical terms should go to Glauber. In 1963, he outlined the basic principles underlying the quantum description of light (in terms of the coherent state) in a paper that was published in the American journal Physical Review Letters (PRL), Volume 10, dated February 1, 1963. Very soon, Sudarshan used the Glauber construct of the coherent state to arrive at a far-reaching result, which he published two months later in the same journal (Vol. 10, April 1, 1963).
According to this result, any quantum state of light can be expressed as a mixture or an ensemble of coherent states expressed in a particular (mathematical) expression called the `diagonal representation'. Individual coherent states in the representation had appropriate weight functions that could take both positive and negative values. This `diagonal state representation', Sudarshan argued, established a formal equivalence between classical and quantum descriptions of the all states of the light field, with the weight functions taking the form of (positive valued) classical probability distributions for most optical processes. But the representation had general validity in that it also correctly reproduced purely quantum effects.
In these cases, the weight functions were no longer the simple probability distributions but were of other forms that included `distribution functions' with negative values.
This mathematical equivalence is now known as the `Optical Equivalence Theorem', a fundamental result in quantum optics. The `Diagonal State Representation', which Glauber has referred to as P-Representation in his subsequent work and is known in literature as Glauber-Sudarshan Representation, has formed the starting point for all later developments in quantum optics.
Reacting to the statement "Glauber and others, including E.C.G. Sudarshan,... worked to explain the observations through quantum mechanics" in The New York Times report, Sudarshan said in his letter: "Actually it is my work, establishing for the first time the (correct) `diagonal representation' of the density operator, that is the basis for all subsequent work in this field. With this diagonal representation not only had I shown the form equivalence between classical and quantum theories of light (all kinds), but it is the only representation from which specifically quantum effects... can be derived.
"The theory referred to as `Glauber's theory' in the report or as `Glauber - Sudarshan' representation in scientific papers is really the Sudarshan `diagonal representation', which was, subsequently, adopted by Glauber and renamed as P-Representation. I would like to assert that literally all the subsequent theoretic developments in the field of Quantum Optics make use of Sudarshan's `diagonal representation', Nobel Prize and citation notwithstanding."
In his remarks to the Indian daily, N. Mukunda, a Professor of Theoretical Physics at the Indian Institute of Science (IISc), Bangalore, and a long-time associate of Sudarshan, had said: "Sudarshan claimed unrestricted validity for a result which Glauber said holds under limited conditions. Sudarshan and J.R. Klauder later put the results on an even firmer footing, justifying Sudarshan's original claims."
C.L. Mehta, a former quantum optics physicist from IIT Delhi who had worked with Sudarshan on the detailed aspects of the Equivalence Theorem, had this to say: "If Glauber's work on quantum optics deserves the Nobel Prize, the work of Sudarshan is even more significant. Even in late 1960s we felt very unhappy when people used to refer to [the result as] `Glauber's P representation' rather than as Sudarshan's diagonal coherent state representation. Some people, of course, took a compromised stand by calling it `Glauber-Sudarshan representation'. However, it was Sudarshan who pointed out the general validity of the representation as against Glauber's suggestion of its applicability in special cases."
"It is not really unusual for the Nobel Committee to selectively pick one individual," points out Girish Agarwal, a quantum optics theorist and former director of Physical Research Laboratory (PRL), Ahmedabad, who is currently a Professor of Physics at Oklahoma State University occupying the Nobel Foundation Chair. "It has happened in recent years, for example, in the case of the Russian physicist V.S. Lekhotov's contribution to laser cooling of atoms which got the 1997 Nobel. Sudarshan certainly made a landmark contribution with his 1963 paper," he added.
"Sudarshan's work was certainly path-breaking. But, perhaps his injudicious use of certain phrases in his paper, may have lessened the impact of his result," says R. Simon, a professor at the Institute of Mathematical Sciences, Chennai. "With his language, he perhaps overstated his case. Today, Sudarshan himself would probably disagree with those phrases. A more carefully written paper would perhaps have had greater impact. But Glauber carefully picked those and attacked Sudarshan's claims of "complete equivalence" (of classical and quantum descriptions) and "one-to-one correspondence" (of weight functions and probability distributions) in his detailed papers," says Simon. However, he drew attention to the carefully worded text of the information document that tends to negate Sudarshan's contribution. "It seems to have been done with a lawyer's bent of mind," he said. Of course, Sudarshan has chosen to take the matter directly to the Nobel Committee's door and has requested a revision of the text.
According to some informed sources, the Nobel Committee apparently did debate Sudarshan's case a good deal. But the final decision was apparently dictated by the fact that Glauber's introduction of the coherent state as a fundamental new entity to describe classical optical fields preceded Sudarshan's work and Sudarshan had cited Glauber's work in his paper. Indeed, the Nobel information document appears to have been drafted skilfully to convey specially this aspect as if priority (to proposing the coherent state representation) was the sole criterion for selection.
Consider the following passage: "The mathematical formalism of quantised fields was developed in parallel with Glauber's work on their applications. E.C.G. Sudarshan drew attention to the use of coherent state representations for the approach to classical physics; at this point he refers to Glauber's work. Together with J.R. Klauder, he proceeded to develop the mathematical formalism of Quantum Optics; their approach is presented in their textbook." (emphasis added).
Jan Nilsson, a Swedish physicist and former colleague of Sudarshan who has assisted the Nobel Committee in this year's deliberations, refused to disclose the manner by which the Nobel Committee arrived at the decision as he was bound by an oath of secrecy. When asked whether Sudarshan's communication to the Nobel Committee changed the perception in any manner, Nilsson said that Sudarshan had said nothing new in it that was not known to the Committee and the Committee had taken all facts into consideration.
Nilsson, however, voluntarily stated that to be considered for the award, a person has to be nominated, along with reasons for the nomination and supporting documents. His remark seemed to imply that perhaps Sudarshan was not nominated at all this year. Nilsson, however, refused to confirm or deny this. But it would indeed be strange that if a field of research came up for the award, the Nobel Committee ignored the work of a person, however important, just because he or she had not been nominated. Nilsson would not throw any further light on the manner of the working of the Committee.
Sources point out how it is not unlikely that Sudarshan may not have been nominated at all. Within the U.S. itself, Sudarshan's constituency in the mainstream physics community is almost non-existent, a result of his drifting into fringe areas of science, including such metaphysical pursuits as transcendental meditation popularised by Maharishi Mahesh Yogi from the late 1970s. It is indeed surprising that Sudarshan has not even been elected to the U.S. Academy of Science, considering the pioneering contributions that he made in several fields of physics, quantum optics being important among them.
His other landmark contribution is the formulation of the V - A Theory of Weak Interactions in elementary particle physics in the late 1950s, in association with Robert E. Marshak. This paved the way for a successful programme of unification of weak and electromagnetic interactions by Abdus Salam and Steven Weinberg during the 1970s. Yet another important work relates to the concept of faster-than-light particle called Tachyon. However, with no evidence of its existence so far, the idea remains hypothetical.
But even with regard to the V - A Theory, Sudarshan has not got the due credit as it is generally referred to as the Feynman-Gell-Mann V-A Theory in physics literature. This, as is generally acknowledged, is mainly because of the unfortunate sequence of events. Feynman and Gell-Mann published their work in January 1958, which actually took the idea from a presentation at a conference in Padua by Sudarshan and Marshak in July 1957, as a paper in a prominent journal. A short paper by Sudarshan and Marshak appeared only March 1958 and the conference proceedings itself appeared only in May 1958. Of course, Feynman has graciously acknowledged this in his famous remark in 1974: "We have a conventional theory of weak interactions invented by Marshak and Sudarshan, published by Feynman and Gell-Mann and completed by Cabibbo. I call it the conventional theory of weak interaction, the one that is described by the V - A Theory."
However, V - A Theory never made it to the Nobel Prize, even though it is a landmark development in the path towards unification of forces. The best time was the early 1980s when Sudarshan's name was, indeed, nominated to the Nobel Committee by well-known Indian physicists. But the possibility was overtaken by events with the latter development of Weinbarg-Salam-Glashow unification of electromagnetism and weak interactions making it to the Nobel grade.
But in the case of quantum optics, there appears to be a genuine case of denial and omission by the Nobel Committee. Even the gracious gesture of Feynman would not seem to have been emulated by Glauber, let alone the Nobel Committee.


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Re: Physics Thread.

Postby Bade » 05 May 2009 00:06

I have often wondered if it was ethical on part of Feynman & Gell-Mann to go publish on stuff heard at a conference before the original inventors did the same. Why was he never pinned down on it ?

There is another aspect which is also something I never understood as alluded to in the above article, Sudarshan being an almost unknown figure in the US even though he remained here mostly.

I have seen him but never met him. At IIT-M (towards the end of his IMSc days) and more recently at a Kerala function in DC where he was proudly claiming his US citizenship as I recall as a guest of honor. Here is a person who was feted to the highest honor in India and even held in awe back home by beginner students like me during our pre-univ years, but finding a sense of pride in becoming a US citizen where they have mostly spurned him.

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Re: Physics Thread.

Postby Amber G. » 05 May 2009 03:04

BTW the link for the Hindu article (also in Frontline – thanks to google - is here:
http://www.flonnet.com/fl2224/stories/20051202002210000.htm

and here is the link about the letter from the same source..
http://www.flonnet.com/fl2224/stories/20051202002610200.htm

Also, if some one wants to judge the “graciousness” of Glauber, one can see this quote given to Harvard’s Crimson at: (Galuber is from Harvard)
http://www.thecrimson.com/article.aspx?ref=510342

Glauber acknowledged Sudarshan’s work but said he was unclear about the particulars of the issue. { sure! Both the guys were in Harvard around that time, working in the same field}

“Professor Sudarshan is a distinguished Indian scientist who has made interesting contributions to several fields,” Glauber said. “I would be fascinated to know what is going on in Texas in this connection.”


Few additional comments:

I have often wondered if it was ethical on part of Feynman & Gell-Mann to go publish on stuff heard at a conference before the original inventors did the same. Why was he never pinned down on it
?

To be fair, no one I know (and that includes a few people who worked closely with Prof Sudershan and Prof. Sudarshan himself) has in public (or even in private, that I know of) raised any “ethical” concerns on part of Feynman (or Gellman) wrt to this… also BTW No noble-prize was awarded for V-A theory (Feynman and Gellman got for other criteria) … (Glauber is another case, as you can see from Prof Mehta’s comments in the Hindu story, there were no big love between Glauber and U of R physicists even in 60’s) .

Feynman writes about the discovery in his autobiography (SYJ) in quite some details.. how he worked the whole night to arrive at the results and how excited he was etc .he was excited that he discovered something really ‘new’ etc
Here I quote from “Surely You’re Joking”
……But the thing that I had trouble with at the Rochester meeting -- the neutron and proton disintegration: everything fit but that, and if it was V and A instead of S and T, that would fit too. Therefore I had the whole theory!

That night I calculated all kinds of things with this theory. The first thing I calculated was the rate of disintegration of the muon and the neutron. They should be connected together, if this theory was right, by a certain relationship, and it was right to 9 percent. That's pretty close, 9 percent. It should have been more perfect than that, but it was close enough.
I went on and checked some other things, which fit, and new things fit,new things fit, and I was very excited. It was the first time, and the only time, in my career that I knew a law of nature that nobody else knew. (Of course it wasn't true, but finding out later that at least Murray Gell-Mann-- and also Sudarshan and Marshak -- had worked out the same theory didn't spoil my fun.)

Sudarshan being an almost unknown figure in the US even though he remained here mostly.


I think with a few exceptions (Like Einstein), and specially now physicists are not considered celebrities and many/most “famous” scientists remain “unknown” if you go by general public.. IMO he is not less “known” than others. In scientific world, IMO , Sudershan is very well known and respected.. (though again this is some what my opinion - it is difficult to judge what's a 'right' amount )

India and even held in awe back home by beginner students like me during our pre-univ years, but finding a sense of pride in becoming a US citizen where they have mostly spurned him.


That may be true, (But I would say he was/is loved by his students here in US too) but it is glass full/half full type thing... some say he was “spurned” by India too ..(there are published reports --and rumors - about a particular Indian noble laureate who could have been more helpful in advocating his case which could have been counted..)

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Re: Physics Thread.

Postby Bade » 05 May 2009 05:49

To be fair to him, if I understood correctly he naturalized only recently unlike the more famous of physicist from Chicago who did win the Nobel. It was an exciting time, the early 80's for young kids to see SC win it and hoping that some day ECG might too. We were naive of course in our expectations of how things work. The latter with his close associations in India was more well known than SC outside of the scientific circles. In fact, I saw SC's picture and a write up on him in a UNESCO newsletter while participating in a non-science high school club activity :) and had wondered who he was. Though every one knew of CV Raman from school books we had never heard of his nephew.

Being bestowed by the Padma Bhushan at a young age and holding key positions in India, shows that India did spurn him less if at all. I am aware of some of politics in Chennai, mostly through second hand rumors .. so will let it be.

As for V-A theory related stuff, it is Feynman's word from his book. My advisor, used to say that Feynman had a knack of seeing multiple ways of the same thing narrated to him by others. He was gifted in a unique way as his 'Feynman diagrams' invention shows. Yet, there were accounts I did read somewhere that Marshak and his then student ECG had discussed their ideas with Feynman and Gell-Mann at the sidelines of the same conference before Feynman's apparent revelation of the same work. It will be largely unknown, where the truth really lies.

ECG may be did not push his case like he did with Glauber later, because of his status then as a young student and cult figure that Feynman had compared to Glauber. My guess only.

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Re: Physics Thread.

Postby Amber G. » 05 May 2009 09:07

Do not want to bore everyone but a few tidbits might be interesting..

As for V-A theory related stuff, it is more than "Feynman's word from his book" in my opinion, I quoted publicly quoted part but to be fair to Feynman, I don't think any one (that I know of, and FWIW I have known/met EGC, and have known few other U or R people like Wolf, Mandl, Marshak, Mehta etc.. since late 60's) raised ethical issue with regard to this about Feynman. Sure ECG and Feynman worked, and were familiar with each others work but I don't think anyone "stolen" credit or anything like that..

In Scientific/student Community (at least in which I hung around as a student in a physics crowd in late sixties) ECG was well known..( I still remember one of my classmates first choice for university to do grad work was Syracuse because ECG was there..).. S. Chandrasekhar was, of course, very big shot, even in those days.. and I though every one knew that he was CVRaman's nephew.. (In fact CVR's all brothers, and quite a few nephews and other family members did extremely well in science .. another one of his nephew was also named Chandrasekhar, and famous by his own work too, caused some confusion..).. Open secret that SC's noble was delayed by a few decades mainly because of Eddington's criticism of Chandra's work.. (and again Eddington politically was a much more powerful fellow) ...

UC's president told an anecdote about a class which SC taught.. The class was small - only 2 students .. Yang and Lee (and it was sometimes audited by Fermi) but he will faithfully drove about an hour for that class (as the class was at U or C campus far from where SC worked)..but it was worth it, as UC's president remarked because that's the only class in the university's history where all the students (and professor) got a noble..:_ :)

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Re: Physics Thread.

Postby Bade » 05 May 2009 09:35

Here is another version from none other than Mukunda a long time collaborator of ECG, about the feelings that ECG and Marshak had about this whole event, in contradiction to giving Feynman et al a pass.
From 1985 archive of Current Science.
http://www.ias.ac.in/jarch/currsci/63/00000064.pdf

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Re: Physics Thread.

Postby Bade » 05 May 2009 09:43

Ahh..now it comes back to me on where I had first read about this whole controversy during my grad school days...it was "Second Creation" by Crease and Mann. Here is the relevant parts.
Second Creation

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Re: Physics Thread.

Postby Amber G. » 05 May 2009 10:17

Bade wrote:Here is another version from none other than Mukunda a long time collaborator of ECG, about the feelings that ECG and Marshak had about this whole event, in contradiction to giving Feynman et al a pass.
From 1985 archive of Current Science.
http://www.ias.ac.in/jarch/currsci/63/00000064.pdf


May be I am missing something but exactly how this "another version" contradicts giving "Feynman a pass"? Perhaps you can quote/highlights the essential part where anyone is accusing Feynman of "stealing" or unethical behavior? ( From what I can see there is nothing i see which is in stark contradiction (or tells the Feynman's story in Autobiography is not true) .. No one is denying that EGC's should not get credit (actually Feynman gives credit)) (Also note that it is not as if Feynman & Gellman were included and EGC were excluded in any Noble citation wrt to V-A theory as no one got noble prize - because of V-A theory-.

I have seen the other reference (the second creation) you have given before... actually it cites the part from SYJ, the ref I gave above.. (I think I know/read/heard more details about this in last 30-40 years than I care to give it here)but bottom line is: I don't think Feynman is to be blamed for this (Much more blame can go to Marshak or E Wolf etc for not making sure that things are properly/timely published etc).. (Bottom line is: it is nothing of the sort that Feynman heard/listened/read the whole part from Marshak/EGC's lectures/notes/paper and then claimed it as his own... and this is a way different than, say Gauber's case, where actual work done/published by EGC was credited to him in Noble's citation)

Anyway these are my opinion only

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Re: Physics Thread.

Postby Bade » 05 May 2009 17:03

No one is claiming precedence in ideas of V-A theory in the context of the Nobel. If you read clearly the section from Second Creation it talks of vicissitudes of publication which caused the feynman paper to come out earlier. The ideas were shared in conversation before Feynman's brainwave and you seem to overlook that point, or why would Mukunda refer to it.

Why should Feynman be given a clean pass in this case, I do not see just on the basis that he got his paper published before by a month, a day or less.

When the top quark was discovered by two different experiments at Fermilab, both are considered discoverers of it. Clearly, somebody saw it first by more than a few hours. :rotfl: yet no one claims to have seen it first in official publications. In fact it was a back to back paper in the same issue as I recall.

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Re: Physics Thread.

Postby Sanjay M » 18 May 2009 02:21

Here's some more of that physics stuff that negi is allergic to:

Quantum Spin Hall Effect Could Lead to Efficient Transistors

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Re: Physics Thread.

Postby negi » 18 May 2009 08:00

^ Oh man; I know my physics (however elementary it might be) but quoting Physics on every other thread without even a relevant context does not make sense . Case in point what have laws of physics got to do with current elections (it is precisely for this reason I posted my comment about quoting physics at drop of a hat) ?

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Re: Physics Thread.

Postby ramana » 29 May 2009 22:50

AmberG and others wht do you think of this book?

Google books

The Holistic Inspirations of Physics


Thanks, ramana

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Re: Physics Thread.

Postby Sanjay M » 19 Jun 2009 12:53

The "Island of Stability" in the periodic table of elements, originally postulated by Glen Seaborg, may finally be showing itself:

http://marcvaldez.blogspot.com/2009/06/ ... nd-of.html

I wonder what the applications could be for such a group of stable superheavy elements?

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Re: Physics Thread.

Postby Rahul Mehta » 19 Jun 2009 13:22

Sanjay M wrote:The "Island of Stability" in the periodic table of elements, originally postulated by Glen Seaborg, may finally be showing itself:

http://marcvaldez.blogspot.com/2009/06/ ... nd-of.html

I wonder what the applications could be for such a group of stable superheavy elements?


Make dumbbells and exercise weight machines that occupy less space.

In some places like Mumbai or Manhattan Center, real estate costs are so high, that people use dumbbells and weights of solid gold instead of iron/steel, as gold (specific gravity 21) occupies about 1/3rd the space compared to iron (specific gravity 7.8 ). With these heavy metals, the space taken by dumbbells and exercise weight machines will further reduce and will save some real estate space in those areas.

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Re: Physics Thread.

Postby Amber G. » 20 Jun 2009 04:23

Ramana - I have not seen/read the book (The Holistic Inspirations of Physics)

Rahulji - Are you sure, you are not confusing with Platinum (whose sp. gravity is about 21 - or even more heavier ones like osmium or iridium) .. cause Gold's sp. gravity is about 19.3. onlee :)

For my money, I will try Tungsten which is almost as heavy as gold, but much cheaper. (Archimedes would not have found the cheating by the royal goldsmith, if the goldsmith cheated by mixing tungsten (in stead of silver) with gold). Of course stuff made out of pavitra/sada neutron (stuff of neutron star) could be 10^12 times heavier than gold ..

BTW the "magic numbers" for nucleons (to form a stable nucleus) are
2, 8, 20, 28, 50, 82, 126.. (Wigner, Mayer and Jensen won Noble for nuclear shell structure)

Side note: Walking in corridors of MIT recently, saw the experimental demo of the "Feynman's reverse sprinkler" which was much discussed here in this thread some time ago.

Problem for Jingo's:

What happens to a positive charge particle (say a proton) at the origin, surrounded by 6 fixed equal positive charges which are at the same distance from the origin in north-south, east-west, up-down position? Of course, due to symmetry, the charge will be at equilibrium, but is it stable equilibrium? (that is, if you disturb the charge just a little, will it stay at the origin or will run away?)

(Hint: If you just take two charges (say east-west or x-axis) the proton in the middle will escape in y-axis (or z-axis) if it is disturbed a little in that direction)

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Re: Physics Thread.

Postby negi » 21 Jun 2009 23:20

^ Guruji just being curious here ....how does one disturb this central charge in isolation without disturbing the surrounding protons ? I mean is it possible to recreate this problem in the real world ?

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Re: Physics Thread.

Postby Amber G. » 22 Jun 2009 03:39

.how does one disturb this central charge in isolation without disturbing the surrounding protons ? I mean is it possible to recreate this problem in the real world ?

Just use a tip of a wand to touch/disturb/move_a_little the central charge. (surrounding charges are all fixed, central charge is free to move).. In real world, it is not too hard to create the problem (and in practical terms may be easy to find the correct answer experimentally than logic/math alone)
(In fact if the answer is "unstable equilibrium" then it will be very hard to keep the charge in center (you need 'exact' center any small error will make it unstable) - like balancing a coin on its edge - while answer of "stable equilibrium" means one can keep the charge at the center.

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Re: Physics Thread.

Postby Amber G. » 15 Jul 2009 23:35

NY times story about Feynman Lectures:
Bill Gates Puts Feynman Lectures Online
Here is the website:
http://research.microsoft.com/apps/tools/tuva/index.html
Eceprts from the story from NYtimes:
Microsoft The new Tuva Web site features annotated videos of Richard Feynman’s physics lectures.
Microsoft Chairman Bill Gates believes that if he had been able to watch physicist Richard Feynman lecture on physics in 1964 his life might have played out differently.

Mr. Gates, of course, is legendary as a Harvard University dropout who went on to create the world’s most successful software firm. He has told associates that if had watched the lectures earlier in his life he might have become a physicist instead of a software entrepreneur.

However, Mr. Gates, who is also well known for his sharp and varied intellectual interests and his philanthropic commitment to education, said this week that he had purchased the rights to videos of seven lectures that Dr. Feynman gave at Cornell University called “The Character of Physical Law,” in an effort to make them broadly available via the Internet.

Microsoft Research announced on Wednesday that Mr. Gates, who purchased the rights to the videos privately from the Feynman estate, BBC and from Cornell University, in cooperation with Curtis Wong, a Microsoft researcher, has created a Web site that is intended to enhance the videos by annotating them with related digital content.

The name “Tuva” was chosen in reference to Dr. Feynman’s decade long — and ultimately unsuccessful — effort to reach the tiny Russian republic of Tuva, which is located in Asia, toward the end of his life.

Mr. Gates said that he had stumbled upon the film version of the lectures a number of years ago, watched them with a friend using a traditional film projector, and “fell in love” with them. The lectures are not the first acquisition of this kind that the software billionaire, has made. In 1994 he acquired the Codex Leicester, a collection of the written work of Leonardo da Vinci, for $30.8 million in an auction. He did not disclose the amount he spent to gain clear title to the Feynman lectures.

“I do think that making science cool to people when they’re young and therefore getting more people to go into it in an in-depth way, I think that’s very important right now,” Mr. Gates said.

The Tuva Web site will be expanded with additional Feynman lectures in the future, Mr. Gates said. When it is completed it will offer searchable transcripts from the lectures as well as commentary from well-known physicists. The site also offers individual viewers the ability to annotate and take notes. Currently, the first lecture has an “extras” features on the right side of the Web page which includes interactive animations and other components.

Mr. Gates said that he remained fascinated with the lectures, which are intended for a freshman college audience, but which he said were within the grasp of his ten-year-old son. He noted that he had recently watched them again while he was helping Mr. Wong put up the Tuva Web site.

“I couldn’t help myself, I watched them one more time,” he said.

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Re: Physics Thread.

Postby Sanjay M » 21 Jul 2009 03:44

Ultra-Dense Deuterium Created (PDF)

Ultra-dense deuterium, a form of "Rydberg matter" has been created within the confines of a solid oxide crystal lattice.

This is probably the most dense form of man-made substance yet created.

Obviously, this material may be a strong candidate for attempts at nuclear fusion.

I notice that they mention metal oxides like palladium and lithium in particular.
Could the existence of ultra-dense deuterium clusters be the reason for speculative evidence about cold fusion phenomena allegedly observed in connection with palladium? (aka. "low-energy nuclear reactions")

Please note in particular the diagram on the last page of the PDF document. Now that evokes an image of something very interesting.

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Re: Physics Thread.

Postby Sanjay M » 08 Aug 2009 17:57

Planck's Law is shown to be violated on the nano-scale, in the near-field regime:

http://physicsworld.com/cws/article/news/40044


Just imagine what this could hold for engineering applications. Imagine being able to cool a nuclear reactor extremely efficiently, without the use of mechanical pumps. Not only could the reactors be made safer, but nuclear submarines could run quieter.

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String Theory - Proof?

Postby Sanjay M » 09 Aug 2009 23:29

Has some proof finally emerged for String Theory?

http://www.physlink.com/News/070709StringTheory.cfm


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