Brian Skinner
@gravity_levity
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"All who have passed the age of 30 are joyless grotesques, endlessly fussing about things of no importance" -George Orwell
Joined September 2009
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I'm finally getting around to publicly posting my lecture notes from the graduate (quantum) condensed matter physics course I'm teaching.
You can find them here, along with my previous lecture notes from freshman-level E&M:
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1/ Who wants to hear some scientific intrigue?
A few weeks ago, a group of physical chemists posted a paper online announcing the observation of superconductivity at room temperature.
Today I posted a comment pointing out something funny in their data.
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@Thinkwert
This was my office copier, where the only button with any wear on it was the 1.
Then people were surprised when I started using it without being told the code.
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Okay, a number of people have asked me to give my opinion about this new claim of "The First Room-Temperature Ambient-Pressure Superconductor".
I am not a real expert in superconductivity, but I am a guy on the internet with opinions, so here we go with some early reactions:
room-temp superconductor at ambient pressure, can be made in a high school chem lab (except for the lead compounds)
@eigenrobot
@literalbanana
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1/ My latest paper is a mathematical model of "prestige bias":
Here's a bit of the back story about where this paper comes from.
When I became a postdoc at MIT, I noticed that people started to treat me differently.
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1/3 The most pervasive toxic behavior in science (and especially theory) is posing: pretending at deep or extensive understanding, or that difficult things are "obvious" or "trivial" for you, or that you have understand something for a long time that others are just learning.
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Finally got one of those yard signs so that I too can join the culture wars
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Received some enlightenment from one of my fellow Physics Olympiad coaches about the difference between heat and work in thermodynamics
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18/ A few updates:
During the last 18 hours I've gotten a lot of emails. Mostly emails from colleagues, the kind where the whole body of the email is something like:
"Wow."
"OMG"
"Nice find!"
"This made my day."
"!!!!!!!!"
"This is the best paper you've written." (Which, ouch.)
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I think I was well past a PhD in physics before I realized that a rocket never actually has to achieve "escape velocity" in order to escape earth's orbit.
It can be lifted arbitrarily slowly, so long as the thrust always exceeds the local gravitational force.
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1/ It's a lovely time of year to take a walk through the woods.
It's also a lovely time to be asking yourself:
"What is the fractal dimension of the trail I'm walking on?"
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1/2
A Russian mathematician is hired by a math department in the US, and is assigned to teach Calculus 1. On the day before her first lecture, she asks a colleague: "what am I supposed to teach in this class?"
The colleague says, "well, it's standard first-semester calculus...
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12/ In fact, the biggest fraud in modern physics was eventually caught because people found the exact same pattern of noise in a number of supposedly independent measurements. Eventually it was proved that he had fabricated dozens of papers' worth of data
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Pierre Agostini of Ohio State Physics has won the Nobel Prize!
I would like to thank the nation of France for imposing a mandatory retirement age, thereby causing all its best scientists to flee to the US in their early 60s.
BREAKING NEWS
The Royal Swedish Academy of Sciences has decided to award the 2023
#NobelPrize
in Physics to Pierre Agostini, Ferenc Krausz and Anne L’Huillier “for experimental methods that generate attosecond pulses of light for the study of electron dynamics in matter.”
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32/ PR's description of the incident is here:
Guys, it's hard to properly convey how surreal this all feels. It's way more drama than I ever thought I would encounter in physics.
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Figure 1(d) does not look like the Meissner effect in any real sense. It just looks like diamagnetism, which lots of non-superconducting materials have.
The upshot from my perspective: it might be something exciting, but for now don't believe it until someone forces you to.
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29/ PR replied with a "rather strong response" to TVR, including a cc to TVR's personal email address.
Shortly thereafter, he got a phone call from TVR.
It turns out that TVR HAD NEVER WRITTEN ANY SUCH EMAIL.
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2/2
"...so you teach the usual things: the definition of a function, limits and continuity, derivatives of polynomial and transcendental functions, that sort of thing."
"Ok," says the Russian.
She comes back the next day and says "so what should I teach in the second lecture?"
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1/ A metal is a very quantum-mechanical object. Just about all its properties arise from the quantum mechanics of a dense collection of free electrons.
So how can we see its quantumness in the electrical resistance?
This is a thread about the phenomenon of "weak localization"
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19/ More importantly, I got a reply FROM THE AUTHORS THEMSELVES.
They took my comment in good faith, and their response is essentially:
"Thanks for pointing this out! We hadn't noticed this peculiar noise correlation. We don't know its origin yet."
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16/ So I wrote a very short comment, stating only exactly what I noticed, and posted it publicly on the arXiv (the scientific server for publicly posting papers). Read it if you're curious: I promise you'll understand the point.
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10/ They have the exact same pattern of random noise. The blue data points are clearly identical to the green ones; they have only been shifted downward by a constant amount.
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This is the most accurate depiction of I've seen of how physicists view the periodic table
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34/ This is probably paranoid, but I'll give a warning anyway:
If anyone gets an email from me about this business, please reply to my MIT email address to confirm that it was actually from me.
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There are two things that jump out to me as seeming shaky:
1. The authors don't actually identify a critical temperature Tc, they only claim that it's "above 400 K". In other words, they can't make the "superconductivity" go away. So are you really sure it's superconductivity?
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11/ These are supposed to be two independent measurements, separated in time and in the value of certain parameters. An exactly duplicated pattern of noise is not something you would expect.
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Some summer school students next week are in for a real treat
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13/ So this observation was potentially a big deal. Too big, in fact: I was completely paralyzed by the question of what to do about it. I spent the next week vacillating between feeling like I had a duty to point this out publicly and feeling like to do so would be irresponsible
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1/9 What's the opposite of a counterclockwise vortex? Try it out for yourself -- the answer will probably surprise you!
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25/ BUCKLE UP, BECAUSE THIS STORY JUST GOT A LOT WILDER
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9/ But when I zoomed in closely on the figure, I saw something very surprising. Look closely at the green and blue data points here:
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2/ Room-temperature superconductivity has been a holy grail in physics for literally over 100 years. If we could find a material that was superconducting at room temperature, it would allow us to transport electrical power for free, and would revolutionize a bunch of industries.
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30/ Both the email asking PR not to criticize the authors, and the supposed discussion between TVR and Pandey were fabricated by someone pretending to be TVR.
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17/ I'm hoping this public comment will mark the end of this little bit of drama in my life. But I'll add to this thread later if something particularly interesting happens next.
(end. for now.)
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11/11
Here is the acknowledgment section, by the way. Probably the best I'll ever get to write.
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My most important slide from the talk tonight was also my most crackpotty:
Trying to convince students that they are not points on a number line of intelligence, but vectors in a 27-dimensional vector space
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15/ In the end, the consensus was pretty clear: no one could imagine an explanation for how that pattern of duplicated noise could arise naturally. Which meant, at the least, that people thinking about the experiment needed to be aware of it.
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22/ I've had another email exchange with the authors, and I will just say:
They are REALLY not backing down from their claims.
They emphasize that they are focused on providing validation of their data, and will only post new data or a response to my note once they have done so.
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14/ I talked, confidentially, to about a dozen experts in the field of superconductivity. I tracked down old theorists who had seen everything and prominent experimentalists and technicians who use the measuring equipment in question every day.
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Arkady Migdal's four-line proof that the electromagnetic field is quantized (photons exist) and that it has infinite energy density
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33/ I swear I am not making this up.
Yesterday I got a Facebook friend request from someone I had never heard of, and I ignored it. I realize today that the person's name was "Wiles Licher". (Same as the email address above)
Zero friends, account one month old.
... should I??
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35/ This thread has become way more sensation than it I wish it were.
So let me say something that probably needs saying: the mysterious "Wiles Licher" is very likely some third-party troll using this controversy as a chance to mess with people.
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I may not be as smart as most of my peers in physics, and I may not work as hard as they do
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2. There are disorder-based reasons why a device can falsely appear to have zero resistance (basically, the electrical current flow can get disconnected from the voltage probe contacts, so that you measure zero voltage drop and therefore conclude zero resistance). So ...
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One of the greatest conversations I ever overheard, at the Theoretical Physics Institute:
"I don't understand how those sprinters can go as fast as 10 m/s, given that each step is 1 m long in order of magnitude and you can only take on the order of 1 step per second"
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... to claim superconductivity you would really want to see a simultaneous Meissner effect: a sharp turn-on of negative magnetic susceptibility below Tc. They claim in the abstract that they demonstrate the Meissner effect, but the only evidence is Figure 1(d).
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24/ I am personally not convinced by his argument, since it fails to explain why the "perfect correlation" between two curves would suddenly disappear at a particular temperature.
But I like the exercise of working from an assumption that the data is real and seeing where you get
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31/ Looking back at the email supposedly from TVR to PR, they realize that it was sent from a mail server called protonmail, which is double-encrypted. Email address <wileslicher
@protonmail
.com>, which neither of them recognized.
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Graphene physicist being asked a question about graphite:
"Sorry, that's well outside my expertise, so it would be unreasonable to speculate."
Any physicist being asked a question about philosophy:
"Allow me to launch into a 30 minute lecture about why this question is trivial."
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I have received my
@threadapalooza
from
@vgr
, so let's do this!
A thread about cool materials, and what makes them so.
@gravity_levity
100 coolest materials (can be anything from elements and molecules to superconductors to whatever they make basketballs and running shoes with)
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Some big personal news: I have accepted a faculty position in physics at Ohio State.
I wrote an overlong blog post recapping the various instances of luck and generosity that got me here, and about what I did right and wrong along the way
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Longtermists are people with enough STEM education to know what an objective function is, but not enough to know what a Lyapunov time is
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3/ So you can imagine how exciting/shocking it was to see two people claim to have found it (). This was a very surprising result, since neither of the constituent materials (gold and silver) are superconductors at any temperature.
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3/ There is no fundamental reason (that we know) why some material couldn't be superconducting at room temperature. But after a century of trying to find such material the best superconductor still needs to be cooled to 90 Kelvin (-183 Celsius).
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20/ I had originally posted some other things from this email, which I have subsequently taken down out of an abundance of caution.
But let me just say: they are not backing down from their claims.
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8/ Here's where I come in. Looking through the paper one evening, I got curious as to why one of their measurements showed lots of random noise at low temperature, but very little noise at high temperature. I thought I might be able to analyze the data by digitizing the plot.
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6/ And the authors were from a reputable institution (the Indian Institute of Science in Bangalore) and the PI had a reputable academic pedigree (for whatever that's worth). So a certain subset of physicists started to get very excited.
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21/ I have encouraged them to post their own public comment about the identical noise patterns, so we'll see what happens.
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1/ Three weeks ago I got a call on my cell phone from an FBI officer who said they wanted to meet in person to talk about my research.
This is a short thread about what I've learned since then about the FBI's interest in basic science / scientists.
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36/ The reality of the claims in the paper will be decided (by people closer to the situation and more expert in the field than I am) on the basis of data and reproducibility. Weird shenanigans are a distraction to the important question.
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Really impressed by the Jazz pioneering the use of irrational jersey numbers
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5/ I think the sheer surprisingness of the result led many people to dismiss the paper right away. It seemed too good to be true.
But if you started looking at the data, it all looked very good and consistent. Multiple independent measurements seemed to confirm superconductivity
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38/ Strangely, though, the "Wiles Licher" account was created July 7. That's 16 days _before_ the paper appeared on the arxiv.
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7/ In the two weeks since the paper was posted, there have already been at least two follow-up papers posted online, and I'm sure that plenty others are in process. Some people (even some I know at MIT) dropped everything to start working on this problem.
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23/ A small update:
Some physics professors are trying to put together the strongest possible plausibility argument for how two such curves really could have the exact same pattern of noise
Here's Prof. Pratap Raychaudhuri from the Tata Institute, Mumbai
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That time I accidentally told my readers to integrate an angle from zero to infinity
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Tell me about a moment in your education when you felt betrayed.
Mine was when I learned that the uncertainty principle doesn't arise just because it's too hard to measure the position and momentum of an electron at the same time.
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Something amazing just happened to me:
I got a letter about physics from an inmate serving a life sentence in Arizona.
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This is a cool effect, which is a standard demo for intro E&M students. But there's nothing quantum about it.
I use polarised filters to explain (some) quantum mechanics to my kids. How is it possible that adding a 3rd filter in between (the one at 45º) some light get to go through the otherwise black rectangle in the middle?
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27/ PR has been working to find the most charitable/plausible explanation for the strange noise patterns. He has also been publicly critical of the authors for not sharing their data or their materials with others.
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A common conversation arc for me:
them: What do you do?
me: I'm a professor
them: Oh really? What do you teach?
me: *briefly confused because I forgot that everyone thinks being a professor is about teaching*
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26/ Let me introduce two new characters in this saga:
(1) Prof. Pratap Raychaudhuri (PR), a professor at the Tata Institute in Mumbai, and an expert in superconductivity and magnetism.
(2) Prof. T V Ramakrishnan (TVR), one of the most famous and senior physicists in India.
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3/3 Adopt a zero-tolerance policy for posing: not in your peers, not in your students, and not in your advisors.
Be aware that posers exist at every level, and they are toxic in all of them. Cut them scruplously out of your circle. Not with malice, but with scrupulousness.
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1/ Condensed matter physics has an obsession with “fractionalization,” which is when an apparently indivisible (quasi)particle seems to split apart into independent pieces.
This is a short thread about fractionalization, with a hint as to why quantum mechanics allows it happen.
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Read the horror that is Scott Aaronson's account of how quantum computing is discussed at Davos:
Here is a quote from a senior vice president at IBM:
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Now that LK99 seems to be over, I feel like I learned something a bit sad about myself.
Throughout the ordeal, I mostly founding myself rooting inwardly to be proven right, rather than rooting for the outcome that was most interesting scientifically.
:-/
More
#LK99
good/bad news. Good news is more results have been reported. Bad news is exactly the same. NTU, an excellent university which has sent its students as PhD students and postdocs to CMTC over the years, reports insulating resistivity increasing with decreasing T and...
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Physicists' hell is a place where all physical phenomena are described by mathematical functions that do not admit a Taylor expansion.
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28/ Today PR received an email from his famous and distinguished colleage TVR, asking him to not criticize Thapa and Pandey (the authors of the original paper), and to be patient. At the bottom of the email was a forwarded friendly discussion between TVR and Pandey.
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2/3 Posing is a way of weaponizing people's insecurities against them. It comes from a place of either genuine sociopathy, or (more commonly) personal insecurity.
In the latter case, it becomes the "best defense is a good offense" approach to trying to make it in science.
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40/ PR reports seeing a single public message on the Wiles Licher facebook page:
"Remember: Julius Caesar went too far!"
What I saw was the less threatening message "Julius Caesar. The Caesar that did not stop." So I hope PR is remembering wrong.
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There is an ironclad rule in academia: the more important you are, the longer you wait to prepare your talk.
There is a guy sitting next to me who is making his slides while the speaker before him is taking questions and I am in awe.
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This thread collects some of my favorite past threads about physics and physics-adjacent topics
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39/ Small update:
The Wiles Licher facebook account and the protonmail email account have both apparently been deleted.
PR is convinced from the fake emails that this imposter was "bright" and "subtle", good enough to convincingly mimic TVR:
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Why are there so many songs about love and so few songs about how great it is to have a paper accepted without revision?
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1/6
I have become worried that the current emphasis on "active learning" in physics classes is providing cover for bad teachers.
In case you hadn't noticed, every physics department has bad teachers: people who are not good at or not invested in explaining things clearly.
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37/ So please don't think I'm weaving a conspiracy theory against the authors or anyone else.
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Could you pass the qualifying exam for the (high school) USA Physics Olympiad team?
Try out this problem that I wrote for last year's exam:
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It's easy for me to get caught up in the many shortcomings of my career and myself.
But you know what? Today I went to the Center for Theoretical Physics at MIT and gave an hour-long talk about quantum entanglement. If my 16-year-old self heard about this he'd be over the moon.
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In a job interview someone asked me "what do you want to become known for?"
I said "I think it's a mistake to try to predict what people will get excited about. All you can do is follow opportunities to do good/creative work when you see them"
and friends I did not get a callback
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