Physics Discussion Thread

[Nandu]

On a lighter vein, just a fun video that demos some basic physics ideas.
The levitating slinky.

[Vayutuvan]

On a lighter vein, just a fun video that demos some basic physics ideas.
The levitating slinky.

Fun video - just watched with my 12 year old. He really seemed to have understood the explanation. Thanks for posting this. I read the news about the research but did not know there was an you tube video of it.

[Bade]

Looks like the buzz on the Higgs boson is going to hit a crescendo this week. Already the media is talking about it. The existence of the Higgs is the most safest prediction for now. Should have posted it in the predictions thread.

[negi]

^So sir if it's existence is experimentally proved, what next ? Will it help answer the hierarchy problem ? Btw just curious is the concept of supersymmetry introduced at Bachelors/Masters degree level in India ? I am struggling to get my head around it.

[Bade]

Negi, Supersymmetry is not even introduced at graduate level in the US unless you are into doing theory as opposed to experimental HEP. It will still remain an unproven theory, irrespective of Higgs being discovered and its mass established. In simple terms Higgs mechanism is what gives particles their mass.

http://en.wikipedia.org/wiki/Higgs_mechanism

http://en.wikipedia.org/wiki/Supersymmetry

[Bade]

On how to look for the Higgs.
http://youtu.be/ktEpSvzPROc

What is the Higgs?
http://youtu.be/QG8g5JW64BA

[SaiK]

I think the bottom most ring in the slinky still held up by the previous ring, and so on and so forth till the ring that is collapsing actually is the immediate previous for release.

[Altair]

Forgive me if I understand it incorrectly, Is it possible to De-Higgs,Boson a space ship and hence make it travel faster than light since there is no 'mass'?

[SaiK]

now, i am all confused.. on these discoveries.. i thought i got to a hold of it.. now, i am going back.. perhaps someone can clarify in aam clarity.

[Bade]

The answer is no, not possible, just as much as it is not possible to change the spin of an electron. The mass is a fundamental property of the particle. You cannot increase the mass of the photon from zero to a finite value to slow it down either. If you could keep doing that incrementally, then at some point you could move faster than the speed of those photons.

[Altair]

There are some tamil folks referring to this particle as "Rajinon" after our superstar! rofl

[Multatuli]

This thread is a veritable repository of wonderous ideas.

While surfing I came across this, not sure what to make of it, but it certainly got me excited:

http://www.globalone.tv/group/quantumqu ... olographic

[SaiK]

http://www.thehindu.com/education/resea ... epage=true
nice

" Everybody is a genius. But if you judge a fish by its ability to climb a tree, it will live its whole life believing that it is stupid"

[Bade]

Interview with AK Raychaudhuri, whom I never met in person being on the wrong side of the divide. But I see some familiar faces in there who was one of his students and was a young recruit during my UG days in Cal.

http://www.youtube.com/watch?v=S7gReG3S ... re=related

[SaiK]

Did Usain Bolt REALLY run 100m in 9.63 seconds?

any aam term explanations?

[Murugan]

Recommended Books:

1) Maya in Physics

by N C Panda

2) The Holographic Universe

by Michael Talbot

[lakshmikanth]

Everyday I learn something new.

I thought I had seen all the mysteries that QM presents, until I came upon this gem of an experiment:

http://en.wikipedia.org/wiki/Wheeler%27 ... experiment

Even more bizzare is this one:

http://en.wikipedia.org/wiki/Delayed_ch ... tum_eraser

Which says roughly this: A quantum entity chooses to behave as a particle OR wave *after* it has passed through any interfering obstructions!!!!!

More here:

http://www.bottomlayer.com/bottom/kim-s ... ly-web.htm

And a paper that attempts to explain it (and does a somewhat OK job of explaining it off as a Bayesian conditioning that does not violate causality. I got the Bayesian conditioning part, but still trying to work out the causality part):
http://arxiv.org/abs/1007.3977

[Amber G.]

Sorry if posted before, but thought it may be of interest here...
9 Scientists Receive a New Physics Prize

The prize in dollars (or rupees) is many times more than a Noble. It is financed by a single rich person. EACH of the 9 got $3 million dollars.

From above:

Physicists are rarely wealthy or famous, but a new prize rewarding research at the field’s cutting edges has made nine of them instant multimillionaires....

The nine are recipients of the Fundamental Physics Prize, established by Yuri Milner, a Russian physics student who dropped out of graduate school in 1989 and later earned billions investing in Internet companies like Facebook and Groupon.

“It knocked me off my feet,” said Alan H. Guth, a professor of physics at the Massachusetts Institute of Technology who was among the winners. He came up with the idea of cosmic inflation, that there was a period of extremely rapid expansion in the first instant of the universe.

When he was told of the $3 million prize, he assumed that the money would be shared among the winners. Not so: Instead, each of this year’s nine recipients will receive $3 million, the most lucrative academic prize in the world. The Nobel Prize currently comes with an award of $1.2 million, usually split by two or three people. The Templeton Prize, which honors contributions to understanding spiritual dimensions of life, has been the largest monetary award given to an individual, $1.7 million this year.

The $3 million has already appeared in Dr. Guth’s bank account, one that had had a balance of $200. “Suddenly, it said, $3,000,200,” he said. “The bank charged a $12 wire transfer fee, but that was easily affordable.”

One of the recipient is an old friend (we attended same schools etc.) .. some in brf may know him well
http://www.iitkalumni.org/Ashok%20Sen.pdf

Added later: Bade has posted it here

[Bade]

Giant Gas Cloud Surrounds Our Milky Way Galaxy

Researchers think the mass inside this halo could be the answer to what's called the "missing baryon problem." Baryons are a class of subatomic particles that includes the protons and neutrons that make up the atoms inside stars and galaxies.

Theories of the formation and evolution of the universe predict there should be many more baryons than we see. In fact, the baryons that have been accounted for in our local cosmic neighborhood are only half of those predicted to exist there. [8 Baffling Astronomy Mysteries Today]

Galaxy-shrouding gas haloes, such as the one around the Milky Way, may be the hiding spot for many of these missing baryons.

"We know the gas is around the galaxy, and we know how hot it is," Anjali Gupta, lead author of a paper reporting the findings in The Astrophysical Journal, said in a statement. "The big question is, how large is the halo, and how massive is it?"

Follow-up observations by the XMM-Newton and the Suzaku satellite indicate that the gas is as heavy as 10 billion to 60 billion suns.

"Our work shows that, for reasonable values of parameters and with reasonable assumptions, the Chandra observations imply a huge reservoir of hot gas around the Milky Way," said co-author Smita Mathur of Ohio State University in Columbus. "It may extend for a few hundred thousand light-years around the Milky Way or it may extend farther into the surrounding local group of galaxies. Either way, its mass appears to be very large."

[Amber G.]

Sorry if posted before, but thought it may be of interest here...
9 Scientists Receive a New Physics Prize

The prize in dollars (or rupees) is many times more than a Noble. It is financed by a single rich person. EACH of the 9 got $3 million dollars.

More about this person, after putting $27,000,000 in prize money.. he puts some more..

From Scientific American blog.
Internet Billionaire Ponies Up More Cash for Physics Prizes

Tech investor Yuri Milner, who shook the physics world two months ago by dishing out $27 million to the nine inaugural awardees of his Fundamental Physics Prize Foundation’s namesake award, has just sweetened the pot.

Milner’s organization today announced the addition of a new award, the Physics Frontiers Prize, which will place three individuals in the running for the $3-million Fundamental Physics Prize and bestow $300,000 on those who do not win it. This latest program, plus the $100,000 New Horizons in Physics Prize for young researchers, makes three big-money awards that the Milner Foundation promises to bestow.

The prizes are meant to recognize major achievements in fundamental physics—primarily theoretical physics, if the first batch of Fundamental Physics Prize laureates is any indication—with a preference for recent advances.

In a prepared statement, the organization said that the first crop of three Physics Frontiers Prize laureates would be announced by the end of the year. They will automatically become nominees for the multimillion-dollar Fundamental Physics Prize, which will be awarded in the first three months of 2013. Milner’s foundation intends to announce up to three winners of the first New Horizons in Physics Prize by December as well.

The graphic below shows how Milner’s cash awards (starred) compare with the other big-money accolades in the field. Money isn’t everything—and no award may ever match the prestige attached to a Nobel Prize—but dollar figures at least allow a quantitative means of comparing different prizes.

[member_22605]

^ May god bless him and may we have more such people!

[ramana]

AmberG and Bade,

Please expalin the new Nobel for Physics. The subject is quantum optics. The radio guy said the interaction of light and matter. I know a little bit about Einstein's work.

[Amber G.]

Nobel Prize in Physics goes to Serge Haroche and David Wineland.

In the field of quantum optics. I think Nobel committee had a chance to redeem it by recognizing the work of Sudarshan in this field but his pioneering work in this field is still not recognized by the this committee. (worse his work was wrongly credited to Glauber and Glauber was awarded the prize a few years ago)

he Nobel Prize in Physics

David Winelandfrom is from NIST(National Institute of Standards and Technology and the University of Colorado.) and Serge Haroche is from the College de France in Paris Ecole Normale Supérieure.

[SaiK]

So, how many quantum bits can be stored in a single digital bite?

[Amber G.]

Ramana,

Standard physics text books (or wiki for that matter) do a good job in explaining Quantum Optics as this filed is old. For a long time IIT Delhi had ( I think now retired) Prof Mehta who was a pioneer is this field and inspired many IIT physics students. Not to mention Sudarshan is also a great teacher . If any one had listened to them, one will agree that they were very good teachers so try to look some thing written by them.

Here is another great resource..
Particle control in a quantum world

The above is a "layman's summary" of the work on the Nobel site.

NYTimes story, IMO for example, did not impress me as far as scientific content.

[Mort Walker]

Amber G,

Thank you for the link, it was interesting to read. A very precise clock is extremely important to a microwave (radio) engineer. It means it has very low phase noise or clock jitter. Phase noise is best described as the spectral power density at an offset frequency from the main carrier frequency. This is extremely important as it allows the practical implications of precise imaging - that is you can better determine position and velocity. This benefits every thing from medical imaging to more accurate missile guidance.

[ramana]

Thanks AmberG.

Link to the Sci Am article by Monroe and Wineland

Quantum Computing with Ions

Now I recall a former BRF member was also into this area of QC.

[Amber G.]

From an old post of Bade ..

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

I did post that from what I know, Feynman always gave credit to ECG Sudarshan But something caught my eye recently from the book The beat of a different drum: The life and science of Richard Feynman. This is what Feynman said in 1963 while talking about V-A theory.""The V-A theory that was discovered by Sudarshan and Marshak, publicized by Feynman and Gell-Mann"

Feynman also talks about in SYJ biography. ..

Just for fun ... some one gave me a link of this youtube video (about 7 minutes) of 2010 Dirac prize (ECG was one of the recipient) which has some Dirac stories..

[Vayutuvan]

ALPHA CENTAURI has an earth-mass planet!

Huge news! Astronomers have announced they have found a planet orbiting one of the stars making up the most famous star in the sky: Alpha Centauri, the closest star system to our own! At 4.3 light years distant, this is far and away the closest exoplanet known… and of course, it has to be.

But the downer is the planet is too hot

The planet orbits close in to Alpha Cen B, and is technically called Alpha Centauri Bb – planets have lower case letters assigned to them, starting at b. Its mass is only 1.13 times the Earth’s mass, making this one of the lower mass planets yet found! But don’t get your hopes up of visiting it – its period is only 3.24 days, meaning it must be only about 6 million kilometers (less than 4 million miles) from its star. Even though Alpha Cen B is a bit cooler than the Sun, this still means the planet is baking hot, far too hot to sustain any kind of life as we know it, or even liquid water.

[Vayutuvan]

AT LHC, they found evidence that SUSY could be seriously flawed/wrong.

Popular physics theory running out of hiding places By Pallab Ghosh

[Multatuli]

Professor Michio Kaku explains and discusses some interesting subjects.

http://bigthink.com/michiokaku

http://bigthink.com/blogs/dr-kakus-universe

[Multatuli]

MinutePhysics

From Wikipedia, the free encyclopedia

MinutePhysics (styled without a space) is a series of educational videos
created by Henry Reich and disseminated through YouTube. Reich's stated goal
is "to get people excited about learnin'." Reich's videos include time-lapsed
drawing to explain physics-related topics in around one minute.
The most popular MinutePhysics video, with more than 2.1 million views,
explains a quantum physics thought experiment known as Schrödinger's cat.
Another popular MinutePhysics video features Reich explaining why pink is not
actually a color. Reich has also uploaded a series of three videos
explaining the Higgs Boson.

MinutePhysics has collaborated with Vsauce, as well as the director of the
Perimeter Institute for Theoretical Physics, Neil Turok.
MinutePhysics also uploaded a popular video, which was an open letter, to
President Barack Obama, on the topic of high school Physics education.
MinutePhysics is also a channel that is able to be viewed through YouTube
EDU. Videos from MinutePhysics have been featured on Huffington Post, NBC, and
Gizmodo.

http://www.youtube.com/user/minutephysics

[Bade]

http://www.nature.com/news/shrunken-pro ... ts-1.12289
Shrunken proton baffles scientists

Researchers perplexed by conflicting measurements.
http://www.nature.com/news/shrunken-pro ... ts-1.12289

http://www.sciencemag.org/content/339/6118/405.full.pdf

If the results pan out for other muonic systems then QED could be in trouble.

An older news item from 2010 on the proton size measurement.
http://www.nature.com/news/2010/100707/ ... 0.337.html

The proton shrinks in size

Tiny change in radius has huge implications.

Geoff Brumfiel
Part of the laser facility needed for the experiment for the determination of the radius of the proton.Measurements with lasers have revealed that the proton may be a touch smaller than predicted by current theories.PSI / F. Reiser

The proton seems to be 0.00000000000003 millimetres smaller than researchers previously thought, according to work published in today's issue of Nature1.

The difference is so infinitesimal that it might defy belief that anyone, even physicists, would care. But the new measurements could mean that there is a gap in existing theories of quantum mechanics. "It's a very serious discrepancy," says Ingo Sick, a physicist at the University of Basel in Switzerland, who has tried to reconcile the finding with four decades of previous measurements. "There is really something seriously wrong someplace."

Protons are among the most common particles out there. Together with their neutral counterparts, neutrons, they form the nuclei of every atom in the Universe. But despite its everday appearance, the proton remains something of a mystery to nuclear physicists, says Randolf Pohl, a researcher at the Max Planck Institute of Quantum Optics in Garching, Germany, and an author on the Nature paper. "We don't understand a lot of its internal structure," he says.

From afar, the proton looks like a small point of positive charge, but on much closer inspection, the particle is more complex. Each proton is made of smaller fundamental particles called quarks, and that means its charge is roughly spread throughout a spherical area.

Physicists can measure the size of the proton by watching as an electron interacts with a proton. A single electron orbiting a proton can occupy only certain, discrete energy levels, which are described by the laws of quantum mechanics. Some of these energy levels depend in part on the size of the proton, and since the 1960s physicists have made hundreds of measurements of the proton's size with staggering accuracy. The most recent estimates, made by Sick using previous data, put the radius of the proton at around 0.8768 femtometres (1 femtometre = 10-15 metres).
Small wonder

Pohl and his team have a come up with a smaller number by using a cousin of the electron, known as the muon. Muons are about 200 times heavier than electrons, making them more sensitive to the proton's size. To measure the proton radius using the muon, Pohl and his colleagues fired muons from a particle accelerator at a cloud of hydrogen. Hydrogen nuclei each consist of a single proton, orbited by an electron. Sometimes a muon replaces an electron and orbits around a proton. Using lasers, the team measured relevant muonic energy levels with extremely high accuracy and found that the proton was around 4% smaller than previously thought.

ADVERTISEMENT

That might not sound like much, but the difference is so far from previous measurements that the researchers actually missed it the first two times they ran the experiment in 2003 and 2007. "We thought that our laser system was not good enough," Pohl says. In 2009, they looked beyond the narrow range in which they expected to see the proton radius and saw an unmistakable signal.

"What gives? I don't know," says Sick. He says he believes the new result, but that there is no obvious way to make it compatible with years of earlier measurements.

[SriKumar]

^^^ Is there any info. on why was this experiment run in the first place? If the size of proton was well-known and understood, what was the intention behind re-checking it with a muon particle? Or were they looking for something else (e.g. 'characterizing' the muon, or calibrating the experimental procedure for another experiment) and stumbled into this?

Also, if there is any write-up on the model used to estimate proton size based on such experiments (electron or muon), please to provide a link or two (may not understand all of it but am interested in the technique and mathematics used).

[SaiK]

The next gen data storage would be DNA structure assimilation of biological information. It is all about patterns, and similar to quantum.. while I was thinking, someone cracks it!

http://www.extremetech.com/extreme/1346 ... ingle-gram

see video in the link.

[Vayutuvan]

The problem with DNA is transfer (read/write) speeds. Probably archival and data warehousing is fine with data mined to faster memories.

[Bade]

Srikumar, the accuracy of the size measured should in a way relate to dwell time of the probing particle. Muons being almost 200 times heavier than the electron is the next lepton available and can be created copiously enough for such experiments. That is the motivation enough, as in increased accuracy of size measurement, a better probe than an electron. Protons have internal structure (made of quarks) and are not point particles like electrons and muons, who do not have internal structure.

The QeD (Quantum electrodynamics) calculations are not straight forward to be explained in simple terms. The link with Helen Margolis article in sciencemag refers to it. If I find something simple will post. Even I am no expert on the theory side of things. All QED calculations can be looked upon as perturbation terms with decreasing significance. The mystery is perhaps in the recipe or the formulation itself. There will be more articles written by experts for aam aadmi soon will be my guess.

This is another well written and concise article on the same topic.
http://physicsworld.com/cws/article/new ... we-thought

And this one is perhaps as close one will get from a theorist pov on the result and the model calculation you are after.
http://hermes.ihep.su:8001/pool/mass/jo ... 93/555.pdf

[Bade]

Srikumar, just for completeness if you have the stomach to pursue this further, a PhD thesis like the one below, will summarize things better with a complete synopsis of the topic.
http://www.qucosa.de/fileadmin/data/quc ... 0-7255.pdf

This one has some nice description on e-p scattering calculations.
http://cds.cern.ch/record/412151/files/9912031.pdf

[SriKumar]

Thanks for the several links....they're in increasing order of complexity . Went through the first one...start simple, right? . The Ph.D thesis, though a tad heavy, actually has some detailed explanations and a description of the experimental set-up which is of interest to me. I wont pretend that I know QED, but that is part of the fun...to see if can one make sense of it with a limited knowledge of the area and some reading. (On an unrelated note, it seems like this issue is being mulled over for 3+ years now).

[Bade]

Most students when they take Field theory classes in grad school, at most one discusses or learns some toy model in abstract idealized case, the real calculations to do with the real world or close as it can get to it is left for one to explore. No wonder it is only the theorists who have the time or inclination to do that.

In any case, enjoy a selected reading of chapters from the thesis. It seemed to me like a good summary which I myself will have to indulge in with a fresh mind, not for bedside reading. The two links describe the two different approaches, spectroscopy in one case and lepton scattering in another case.