Physics Discussion Thread

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Amber G.
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Re: Physics Discussion Thread

Post by Amber G. »

For those want to see/understand/appreciate more of the 2020 Physics Nobel - experimental side - of Ghez and Genzel - I present you two excellent lectures by them - (Last years APS meeting)

Enjoy.
https://youtu.be/KAoZLiuEvIY?list=PLgxD ... QeV3sGIY_W



https://youtu.be/oXF9jRK6hmo
Amber G.
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Re: Physics Discussion Thread

Post by Amber G. »

Big News: So, first time, we do have a genuine "room temperature" super conductor.
(it is about 15C, a little chilly but still can be called room temperature .. but about 2.5 Million times standard room pressure (about 250 GPa) !) ..

https://www.youtube.com/watch?v=onB0w3_Su9I
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Re: Physics Discussion Thread

Post by Amber G. »

Nice article about this ... We have reached a long-sought goal. The catch is that their room-temperature superconductor requires crushing pressures to keep from falling apart...
https://t.co/6rtbjw9I4r?amp=1
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Re: Physics Discussion Thread

Post by Amber G. »

About a year ago, there was quite a bit of discussion about IISc's group's claim(s) about room temperature superconductivity using gold-silver nano structures..(See my old post below for context - there were quite a few posts by many then)..

Update on that: For those interested, Prof Arindam Ghosh we will talk about the latest on gold-silver nanostructures at Penn State CAMP seminar series on Nov 30...Link: https://science.psu.edu/event/unconvent ... structures

**** One year old post by me for context:
Amber G. wrote:
tandav wrote:https://theprint.in/science/why-the-phy ... ry/116838/

Interest in the IISC breakthrough claims in Room Temp SuperConductivity seems to be have ebbed... Anyone closer to the IISC research team can update us further.
Yes. Last I heard was that their patent is in the public domain. (http://www.physics.iisc.ernet.in/~arind ... nt/]<link> As far as publication in reputable journal (by the IISc Scientists - none.. but their tweeter accounts have "More update soon" for a long time.
I do know quite a few people in IISc and some are good friends and I am in contact with them. I met one (who recently was honored by Padma award from GoI), a friend physicist who gave a key-note address in US without mentioning this. (Many IISc scientist avoid talking about this)

Disclaimer: I am skeptic. I am also too close to people involved in the story (Please read the story linked by Tandav) Prof TV Ramakrisnan was my prof, Prof. Raychaudhuri is a friend (and not really liked by that IISc group as he is also in the same field). My specific technical questions to authors were answered by polite non-answers or were ignored. (Naturally most people, as it happens in physics, in the field are quiet and are in no hurry to judge and will wait till all the results are in.)

There are at least 10 labs in India alone which they can ask or cooperate with to duplicate/validate finding or ask others (even IISc colleagues outside their group) to look through their data/experiment --- In my humble opinion --( I think they can avoid much of the confusion and can still preserve their patent/commercial investment).
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Re: Physics Discussion Thread

Post by Vayutuvan »

I bring you this news with a heavy heart. I and my two high-school kids visited this telescope about 7-8 years back. It was a grand structure to behold.

https://www.nationalgeographic.com/scie ... collapses/
The Arecibo Observatory’s suspended equipment platform collapsed just before 8 a.m. local time on December 1, falling more than 450 feet and crashing through the telescope’s massive radio dish—a catastrophic ending that scientists and engineers feared was imminent after multiple cables supporting the platform unexpectedly broke in recent months. No one was hurt when the 900-ton platform lost its battle with gravity, according to staff at the observatory in Puerto Rico.
...
Amber G.
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Re: Physics Discussion Thread

Post by Amber G. »

Vayutuvan wrote:I bring you this news with a heavy heart. I and my two high-school kids visited this telescope about 7-8 years back. It was a grand structure to behold.

https://www.nationalgeographic.com/scie ... collapses/
The Arecibo Observatory’s suspended equipment platform collapsed just before 8 a.m. local time on December 1, falling more than 450 feet and crashing through the telescope’s massive radio dish—a catastrophic ending that scientists and engineers feared was imminent after multiple cables supporting the platform unexpectedly broke in recent months. No one was hurt when the 900-ton platform lost its battle with gravity, according to staff at the observatory in Puerto Rico.
...
Not entirely a surprise as the Observatory was heavily damaged in the hurricane and was scheduled to be scrapped but still quite sad news.
Arecibo observatory data was often used by scientists in Indian Institute of Geomagnetism for a long time.
(Not sure, but they say that Radio telescope is gone but they still might keep the observatory to do other data collection with other instruments .. hopefully new US admin may allow it to do that)
Trumps dislike of science (and brown people of Puerto Rico) was one of the main cause, IMO, after the hurricane did a lot of damage in the island.
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Re: Physics Discussion Thread

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Today, in a new paper in the journal Nature, a team of four physicists led by Saïda Guellati-Khélifa at the Kastler Brossel Laboratory in Paris reported the most precise measurement yet of the fine-structure constant. The team measured the constant’s value to the 11th decimal place, reporting that α = 1/137.035999206(11). (The last two digits are uncertain.)
As fundamental constants go, the speed of light, c, enjoys all the fame. The fine-structure constant, has no dimensions or units. It’s a pure number that shapes the universe to an astonishing degree — “a magic number that comes to us with no understanding,” as Richard Feynman described it. Paul Dirac considered the origin of the number “the most fundamental unsolved problem of physics.”..

Remarkable experimental physics..

https://www.nature.com/articles/s41586-020-2964-7
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Re: Physics Discussion Thread

Post by Vayutuvan »

Isn't the constant a rational number?
Amber G.
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Re: Physics Discussion Thread

Post by Amber G. »

^^^ No.. (Many wondered - people like Dirac and Feynman - to find the significance of this number. Wondered if there is something unique (mathematically) with 137 or it has deeper meaning. Pauli, among others, was really preoccupied with the question of why the fine-structure constant has this value.He died in Room 137 of the Rotkreuz hospital in Zürich) .

Current thinking is, it is just a constant.
My favorite: 137 is the largest prime factor of 123456787654321. :) .

BTW - Element Feynmanium (atomic number 137!) is supposed to be one of the last stable element in the periodic table. :).
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Re: Physics Discussion Thread

Post by Vayutuvan »

My favorite: 137 is the largest prime factor of 123456787654321.
That is a nice coincidence, so is Feynmanium.
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Re: Physics Discussion Thread

Post by Amber G. »

Celebration of 128th Birth Anniversary of S. N. Bose & 25th S. N. Bose Memorial Lecture.

1st January, 2021
2:00 PM
Image
Amber G.
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Re: Physics Discussion Thread

Post by Amber G. »

Physics Photo Of the Day:

Physicist Richard Feynman experiencing the physics of snowball throwing first hand at Cornell.
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Amber G.
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Re: Physics Discussion Thread

Post by Amber G. »

Very sad to see the passing of Nobel laureate Martinus Veltman, a giant of particle physics. In the 1960s he was one of the few who kept believing in gauge theories as the ultimate description of nature. He will be missed for his razor-sharp mind and boundless passion for physics.
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Re: Physics Discussion Thread

Post by Amber G. »

Another famous scientist, Narinder S. Kapany, ‘Father of Fiber Optics,’ Died recently. He was 94 years old.
Several times I have mentioned him in Physics or other dhaga's here in Brf about his work.

He never won a Nobel, but was one of the great pioneer/engineer who as a an young Engineer at Cornig did pioneering work to make fiber optics a success. Fortune named him one of seven 'Unsung Heroes' in their 'Businessmen of the Century' issue in 1999.
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Re: Physics Discussion Thread

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Delighted to share this news here:

Prof Rohini Godbole, from the Centre for High Energy Physics at IISc, has been awarded the Ordre National Du Merite, or National Order of Merit, considered to be among the highest distinctions bestowed by France.

I have talked about her a few times in this dhaga - she has won several awards, including a Padma Sri.
Top France award to physicist Rohini Godbole
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Amber G.
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Re: Physics Discussion Thread

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Amber G. wrote:Another famous scientist, Narinder S. Kapany, ‘Father of Fiber Optics,’ Died recently. He was 94 years old.
Several times I have mentioned him in Physics or other dhaga's here in Brf about his work.

He never won a Nobel, but was one of the great pioneer/engineer who as a an young Engineer at Cornig did pioneering work to make fiber optics a success. Fortune named him one of seven 'Unsung Heroes' in their 'Businessmen of the Century' issue in 1999.
Shri Narinder Kapany is being honored with Padm Vibhushan this Jan 26. (I am glad that he is being honored now).
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Re: Physics Discussion Thread

Post by Amber G. »

An accurate, funny and very helpful clip for all physics teachers..
https://youtu.be/-tDWU3A6yTA
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Re: Physics Discussion Thread

Post by rsingh »

One need to know maths.........even to understand this video :(( . Maths and music not my domain. wish I could understand calculus and learn Piano. But no.It is not for Jatts. Therei s not a single Jatt scientist at ISRO and no Pianist. Lahole vila quvat.
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Re: Physics Discussion Thread

Post by Amber G. »

Another physics great passes away today.
Rest In Peace, Steven Weinberg (1933 - 2021)

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Re: Physics Discussion Thread

Post by ArjunPandit »

oh no...om shanti to his soul too
Amber G.
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Re: Physics Discussion Thread

Post by Amber G. »

For the first time ever, the US Physics Team brought home ALL GOLDS in the International Physics Olympiad.
Congratulations to the USA team and to the six team coaches, including Dr. Mark Eichenlaub the Team lead.
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Re: Physics Discussion Thread

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Remembering - Indian-American astrophysicist and Nobel laureate Subrahmanyan Chandrasekhar who died on this day died 1995. Perhaps the greatest mathematical astrophysicist of the 20th century, Chandra as he was known applied hard math to black holes, stellar dynamics, radiative transfer and other fields.
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Re: Physics Discussion Thread

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Some new advances in fusion research using inertial confinement.

Nuclear scientists hail US fusion breakthrough
"This result is a historic advance for inertial confinement fusion research," said Kim Budil, the director of Lawrence Livermore National Laboratory, which operates the National Ignition Facility in California, where the experiment took place this month.
It's too bad the US government won't fund DoE and this work seriously.
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Re: Physics Discussion Thread

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Amber G. wrote:Remembering - Indian-American astrophysicist and Nobel laureate Subrahmanyan Chandrasekhar who died on this day died 1995. Perhaps the greatest mathematical astrophysicist of the 20th century, Chandra as he was known applied hard math to black holes, stellar dynamics, radiative transfer and other fields. ]
I once stumbled onto his Ph.D thesis while browsing through some books in a shelf in my univ. library. I flipped some pages and found an equation was literally did not fit in 1 page- about 8" x 11" page. It went over into the next page for a couple of lines. Hand-written eqn, if I recall right. My head spun when I saw that. I scanned through the page to confirm that there was only one single = sign for the entire set of symbols and parameters. I cannot image how he could hold all that in his head and perform manipulations on the equation and relate each of the (20 or more) parameters to physical quantities.
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Re: Physics Discussion Thread

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Question .
What will happen if temperatures in univers goes down to absolute zero. We know that that universe was a hot soup during initial one second. But energy was not distributed equally and that is why we have blackness where there is no light. Universe is expanding expanding .
Does it means that there are areas where universal temperatures are at absolute zero? Atoms have disinterested in these areas ?
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Re: Physics Discussion Thread

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SriKumar - Yes, Dr. Chandra (as he was known) was an extra-ordinary fellow. There are quite a few anecdote about him in this dhaga. He comes from a *very* famous family. His uncle (CV Raman) also won Nobel in physics and his father and another uncle and *many* cousins are also world renowned. His wife was first graduate physics student of CV Raman etc. (I knew him, a few of his cousins and their family very well - have stayed with them etc).

I highly recommend his autobiography by Wali.

One anecdote, when he was at U of Chicago, and working at Argonne Lab he used to drive around 50 miles from lab just to teach a class with just 2 students. Such was his dedication. In 2010 president of U of C talked about it, he mentioned that that's the only class he knew where 100% of his students (both his students Yang and Lee) got a Nobel in Physics. Somebody corrected him - It turned out that one other fellow used to audit that class, He was Fermi!!! (So not only the professor, 100% of his official students, and even those who just audited the class got a Nobel).
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Re: Physics Discussion Thread

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rsingh wrote:Question .
What will happen if temperatures in univers goes down to absolute zero. We know that that universe was a hot soup during initial one second. But energy was not distributed equally and that is why we have blackness where there is no light. Universe is expanding expanding .
Does it means that there are areas where universal temperatures are at absolute zero? Atoms have disinterested in these areas ?
I don't know what will happen - NO ONE can possibly know if temperature goes to absolute zero - as there will be no life and no one to measure it. At present, ave temperature of the universe, as measured by MW radiation is about 2.7 K.
(Temperature is nothing but average KE of particles)
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Re: Physics Discussion Thread

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Is there any book on this problem. . I am sure theoretical physicist have worked on this. Tried to Google but it is all cold soup.Thanks
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Re: Physics Discussion Thread

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Amber G. wrote:
rsingh wrote:Question .
What will happen if temperatures in univers goes down to absolute zero. We know that that universe was a hot soup during initial one second. But energy was not distributed equally and that is why we have blackness where there is no light. Universe is expanding expanding .
Does it means that there are areas where universal temperatures are at absolute zero? Atoms have disinterested in these areas ?
I don't know what will happen - NO ONE can possibly know if temperature goes to absolute zero - as there will be no life and no one to measure it. At present, ave temperature of the universe, as measured by MW radiation is about 2.7 K.
(Temperature is nothing but average KE of particles)
This is really a very honest answer and is very appreciated! The rest, unless there's some fancy math to it, is all speculation.

They way I understood it, absolute zero implies no KE of atomic nuclei. For that to happen you can't have the forces of gravity and electroweak interaction. I guess you could still have the strong force interaction of sub-atomic particles, but without the other 3, I don't think the universe consisting of atoms could exist. You may just end up with a universe of Boson particles just floating around.
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Re: Physics Discussion Thread

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https://www.sciencedaily.com/releases/2 ... 143516.htm
Got this. But need to read many times to digest information. Quite mind boggling.
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Re: Physics Discussion Thread

Post by Cyrano »

I'm wondering if there is a direct connection between the Indic view of "naad" meaning vibration as being a fundamental cosmic force and all that we are discovering now...
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Re: Physics Discussion Thread

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I do feel this when listening to damru nada.in morning. So distant....as if coming from infinity. So mesmerizing. So pure Ultimate.
I
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Re: Physics Discussion Thread

Post by Amber G. »

Biopic on S. Ulam is released today!
https://youtu.be/SZ2YupFolFA
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Re: Physics Discussion Thread

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Congratulations to the new physics laureate Syukuro Manabe who is all smiles following the announcement of his NobelPrize.
Image

---
The Nobel Prize in Physics 2021 was awarded "for groundbreaking contributions to our understanding of complex systems" with one half jointly to Syukuro Manabe and Klaus Hasselmann "for the physical modelling of Earth's climate, quantifying variability and reliably predicting global warming" and the other half to Giorgio Parisi "for the discovery of the interplay of disorder and fluctuations in physical systems from atomic to planetary scales."
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Re: Physics Discussion Thread

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Today is the birth anniversary of Homi Bhabha.
(Pictured: Bhabha with S Bhagavantam (Director of IISc (left)) and JRD Tata, at the Golden Jubilee celebrations of IISc in 1959)
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Reposting a photo - posted before in brf..

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(Here he accompanies Albert Einstein, Hideki Yukawa and John Wheeler in Princeton, NJ)
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Re: Physics Discussion Thread

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Posting a article which I enjoyed.

Einstein would have been delighted to see we can do this! Really amazing.
Gravity slows time - A person at the top of Mount Everest ages faster than a person at sea level.

(We see this and take care this into account for our GPS system, where clocks on the GPS satellites run faster - very small difference but measurable - Actually on LEO sats, the clocks runs slower while sat on higher orbits, the clocks are actually faster -- something I discussed in other threads )

Now Physicists have managed to measure this difference to the millimeter using a cloud of strontium atoms. (Clock on the top of a table runs faster than one at the floor!)

An Ultra-Precise Clock Shows How to Link the Quantum World With Gravity
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Re: Physics Discussion Thread

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Amber G,

Thanks for the link. It is indeed interesting. What has been done is a fractional frequency shift measurement of 7.6x10^-21 within 1mm of an optical lattice clock. An optical lattice clock operates at optical frequencies as opposed to atomic clocks (Cs & Rb) that operate at microwave frequencies. Therefore it is easier to determine smaller or fractional frequency shifts.

Spacecraft such GPS satellites use Cs or Rb time sources, and implementation of designing and consistently building such apparatus is not an easy task. A lot thanks have to be given to the engineers who designed the apparatus and built these optical lattice clocks.
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Re: Physics Discussion Thread

Post by Mollick.R »

Interesting..... & complex

https://youtu.be/7PHvDj4TDfM



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Re: Physics Discussion Thread

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Just for fun.. pictured below is Mary and her brother - a very famous physicist..Any guesses..

Image
Last edited by Amber G. on 03 Nov 2021 06:20, edited 2 times in total.
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Re: Physics Discussion Thread

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Amber G. wrote:Just for fun.. pictured below is Mary and her brother - very famous physicist..Any guess..
[img].large[/img]
author of Brownian motion ?
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