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5:09 AM

Q: Why does twistronic 'magic angle' graphene have only 180-degree symmetry?

From Graphene superconductors may be less exotic than physicists hoped[1]: Excitement rose earlier this year with the discovery of superconductivity in a similar system[2]: three layers of graphene twisted at their own special angle. Both systems shared a rare, 180-degree rotational symmetry, wh...

I wrote an answer, hope it's right!

uhoh

5:36 AM

Q: How can there only be "11 phonons" in the mirrors of LIGO interferometers?

LIGO is an incredibly sensitive detector of small changes in space due to the passing of gravitational waves and uses some very high-level mathematics and physics and experimental techniques to drive its noise level low enough to make this happen. Ars Technica's refers to the new paper in Scienc...

observational-astronomy gravitational-waves temperature optics ligo

anybody here like quantum mechanics? :-) I've just added a bounty, and mentioned it in comments in this question. If "crystals of atoms" stored in laser traps can have a temperature, this seems to be just "one step beyond" that!

Q: How are LIGO mirrors cooled?

The recent LIGO announcement Observation of Gravitational Waves from a Binary Black Hole Merger has some technical details about LIGO. For example, LIGO is a modified Michelson interferometer. The test masses are 40 kg fused silica mirrors that form a resonant optical cavity. The power of the ...

experimental-physics ligo cryogenics low-temperature-physics

uhoh

5:57 AM

Q: What are, and what has been learned from making plasma crystals in space? Is a tl;dr-like answer possible?

The two articles below describe a set of plasma crystal experiments scheduled for 2019 aboard the ISS in cooperation with German and Russian scientists on the ground. These were not the first but might be the latest and definitely build directly upon previous Russian experiments. Question: In a n...

microgravity russia esa experiment plasma

speaking of trapped atoms :-)

3 hours later…

r/comp_chem

9:09 AM

Computational Chemistry: Eliminating small >100cm-1 imaginary frequencies from TS calculation in Gaussian09

posted on June 22, 2021 by /u/AnCoAdams

Hi guys, I've go a transition state, where the first normal mode has a frequency of -1570.71 that looks like the proton transfer transition state I'm trying to find. However, I have this small second mode frequency -22.52 which I can't eliminate at present. Based on advice on researchgate, I've tried manually displacing this frequency to -1.00 in gaussview to no avail. My curr…

5 hours later…

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1:59 PM

Q: Can a free electron absorb a photon?

Can an already moving electron absorb a photon and show photoelectric effect ? For example in a wire having some current, electrons are already moving, So, if we shine a beam of light having suitable frequency, will it exhibit photoelectric effect ?

electrons atomic-structure

2 hours later…

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4:03 PM

-2

Q: In vanderwall's correction why the excluded volume b is smaller than the molar volume of gas?

This question is from the topic volume correction in vander wal equation . Vgas=Vvessel - nb Where b is excluded volume Now the question i was asked is that why excluded volume is smaller than the molar volume of gas. Please help me answer it.

van-der-waals-behavior

2 hours later…

Nike Dattani

5:52 PM

@uhoh I've forwarded it to a friend who works on the LIGO project (he does have an account at Physics.SE, but does not post very often at all).

@r/comp_chem @Tyberius I've written this comment in case you'd like to keep an eye on it to see how the reddit/comp-chem mods feel about it.

1 hour later…

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7:21 PM

Q: Can alkali-doped exohedral fullerene molecules show superconducivity?

Alkali doped Fullerenes are one of the few organic materials that show superconductivity. However, when attaching a new molecular system to a fullerene doped with an alkali metal, will it still show superconductivity?