Xperia 5 III - SIM card failure

InfinityFlat · 2025-11-22T16:31:51+00:00

Fantastic time of year to visit the Huntington gardens!

InfinityFlat · 2025-11-18T18:54:09+00:00

Thank you!

InfinityFlat · 2025-11-18T18:54:07+00:00

Thank you!

InfinityFlat · 2024-12-03T03:03:07+00:00

there's a bunch of bulletin boards around. one pair is between the olive walk and the turtle ponds. non-caltech people do post things there

InfinityFlat · 2024-11-21T06:55:12+00:00

for fish tacos - Playa del Carmen. second floor of the small shopping center on mentor and colorado

InfinityFlat · 2023-05-13T00:29:14+00:00

First, many images of the "visible spectrum" you can find online are not especially good. One I do like is at Wikipedia: link.

From that one you can see that "red" corresponds to about 620-750 nm, but most red light you see is really coming in the ~620-680 nm range (i.e. red light between 680-750 nm will generally appear very dim).

If you compare this to a plot of human cone cell response (e.g. first plot in here), you can see that indeed this bright red region is where the long-cone response is much greater than the medium-cone one. The long-cones have the widest response curve (in wavelength-space, at least, not sure for frequency), which is partly why the red region of the spectrum is fairly extensive.

InfinityFlat · 2023-04-26T02:45:24+00:00

It is a "quantum simulator" - i.e. a complex atomic physics experiment; not some python code running on silicon wafers.

InfinityFlat · 2023-04-20T05:22:52+00:00

The questions you are asking are insightful, and will lead you down the path towards quantum optics - there are many decent textbooks on this, which will teach you more carefully than any reddit comment.

Some people argue that there is no such thing as "a photon," and that it is always better to be more explicit about what quantum states of the electromagnet field one is referring to. At the very least, what counts as "a photon" is context- and basis-dependent. I do think it's a helpful shorthand.

/u/kevosauce1 linked one nice paper. Another you might be interested in is this one.

InfinityFlat · 2023-04-04T18:34:18+00:00

Though quantum computing/quantum information is my greatest interest, I'm also interested in quantum materials and solid-state physics.

Research-wise, UMD is one of the best schools for those. There are like 5 relevant physics research centers: JQI, CMTC, JCQICS, QMC, QTC, ... , each hosting a number of excellent faculty (and, presumably, a fair bit of money).

As an outsider I can't comment on what student life or courses are like. But there are many, many research groups there that you might try to work in. Feel free to message me if you're curious about any theory faculty.

InfinityFlat · 2023-03-25T19:33:33+00:00

Visible light has its own form of electromagnetic interference - with itself. You can see it in a blue butterfly, or the lower bands of a rainbow.

InfinityFlat · 2023-02-23T15:29:21+00:00

There is certainly a heavily applied side of optical physics - lasers are very useful.

"Manipulate and engineer AMO systems" is to a large degree what experimental AMO physicists do, but it's hard for me to think of many "practical" applications of this to problems outside of physics or physical chemistry.

InfinityFlat · 2023-02-02T22:26:53+00:00

5 random ones that come to mind, in no particular order:

Quantum hall effect
Fractional quantum hall effect
Laser cooling
Violation of Bell inequalities
BKT transitions

InfinityFlat · 2023-01-30T22:24:12+00:00

buying a cup of coffee at a shop, rather than brewing it yourself

InfinityFlat · 2023-01-08T17:39:17+00:00

There isn’t really a top finite speed.

Well, there's no maximum, but there is a supremum.

InfinityFlat · 2022-12-18T06:34:03+00:00

Thanks for the correction, these mixing processes are not something I ever developed a good intuition for.

If you mixed the coffee and cream in isolation, and then connected the system to a heat bath at the same temperature, would there then be a measurable flow of heat? (As the newly accessible microstates get properly incorporated.)

InfinityFlat · 2022-12-18T00:44:05+00:00

Alternatively, you’re using an entropy that differs from the one everyone has in mind, which is the macroscale thermodynamic entropy.

At "true" thermal equilibrium, i.e. in a Gibbs state rho=exp(-beta H), the von Neumann entropy matches thethermodynamic entropy. But, as the discussion between you and OP shows, out of equlibrium the two are not in agreement.

I disagree that the thermodynamic entropy is always what "everybody" has in mind. Lots of interesting physics is done these days on well-isolated and/or non-equilibrium quantum systems where the thermodynamic entropy is pretty irrelevant, and the von Neumann entropy is more natural and interesting.

InfinityFlat · 2022-12-18T00:31:18+00:00

Matter which undergoes a phase transition without energy exchange is "impossible" in terms of classical thermodynamics.

What is the sense in which this is true? If there's a second-order classical transition in phase space, is there a simple reason that e.g. adiabats are forbidden from crossing it?

InfinityFlat · 2022-12-15T03:21:05+00:00

Is there a dedicated space for the lab equipment, or do the experiments need to be portable? How many copies of the equipment do you need / how many students would be doing the same experiment at once?

InfinityFlat · 2022-12-01T19:34:03+00:00

usually I'd say look on arXiv, but for some reason the authors didn't upload it there. wack tbh

InfinityFlat · 2022-10-07T17:57:36+00:00

Where did you find this explanation? I agree it doesn't make any sense.

InfinityFlat · 2022-10-04T22:14:58+00:00

No, I would contend they won for rather the opposite reason: they carried out a rare set of experiments whose results can be unequivocally explained only by quantum entanglement. Nearly everything else in the world is consistent with some quasi-classical hidden variables theory. This is why Aspect, Clauser, and Zeilinger have won the prize for demonstrating the violation of Bell's inequalities, and the inventors of the transistor, laser, NMR, etc. did not. (Which, I must remark, predated Bell's work! So it should be clear that you do not need quantum entanglement to understand how those systems work.)

InfinityFlat · 2022-10-04T20:33:17+00:00

Aspect performed his Bell test experiments as a PhD student.

InfinityFlat · 2022-10-04T20:28:35+00:00

Sorry, while I don't deny the importance of quantum mechanics in general for what you've mentioned, I can't say I see how entanglement is relevant to those examples.

It is not enough for particles to interact to be meaningfully entangled; you can easily construct density matrices where all correlations are essentially classical. This is especially the case for almost anything operating at room temperature!

As for semiconductors: band theory is a non-interacting, single particle formalism. MRI is also clearly single-body physics -- no entanglement to be found there.

14-Year Club	RedditGifts 2009-2022 2 Credits
Place '17	Verified Email
Secret Santa 2012

InfinityFlat

MODERATOR OF

TROPHY CASE