radioactivist

6 ms·

31.
by radioactivist 2y ago
The idea that graphite may contain in inclusions that are superconducting at room temperature is highly speculative (putting it mildly) and not an idea that is taken seriously in the condensed matter physics community.
32.
by radioactivist 2y ago
I've had frontier reasoning models (or at least what I can access in ChatGPT+ at any given moment) give wildly inconsistent answers when asked to provide the underlying reasoning (and the CoT weren't always given). Inventing sourc
33.
by radioactivist 2y ago
I could trace through that example quite quickly and I'm not an expert in logic, so I think you might be exaggerating some statements about difficulty here.
34.
by radioactivist 2y ago
The troubling part is that the references themselves existed -- one was an obscure Russian text that is difficult to find (but is exactly where you'd expect to find this kind of result, if it existed).
35.
by radioactivist 2y ago
By a factor of 10,000,000,000? (that's the ten orders of magnitude needed, since the physical side is out). Algorithmic improvements will make this 10 billion times cheaper?
36.
by radioactivist 2y ago
I had a similar experience with regular o1 about integral that was divergent. It was adamant that it wasn't and would respond to any attempt at persuasion with variants of "its a standard integral" with a "subtle cancell
37.
by radioactivist 2y ago
I think expecting five orders of magnitude improvement from either side of this (inference cost or phone performance) is insane.
38.
by radioactivist 2y ago
So your claim for optimism here is that something today that took ~10^22 floating point operations (based on an estimate earlier in the thread) to execute will be running on phones in 25 years? Phones which are currently running at O(10^12)
39.
by radioactivist 2y ago
Some of these results have been on the arxiv for a few months ( https://arxiv.org/abs/2408.13687 ) -- are there any details on new stuff besides this blog post? I can't find anything on the random circuit sampling i
40.
by radioactivist 2y ago
Out of class evaluations doesn't mean electronic. It could be problem sets, essays, longer-form things like projects. All of these things are difficult to do in a limited time window. These limited time-window assessments are also (a)
41.
by radioactivist 2y ago
I'm a condensed matter/statistical physicist and am very aware of the connections to statistical physics I still think that the committee has completely lost it with this choice. There is a sharp line for me between things that ar
42.
by radioactivist 3y ago
While there certainly are ideas from string theory that have filtered down to CMP, topological insulators are not one of them.
43.
by radioactivist 3y ago
Broader sociological problems aside for a second (academia does have issues for sure), one should keep in mind here that string theory is just a small subfield of physics and is not at all representative of physics as whole (or even theoret
44.
by radioactivist 3y ago
One small point: since the original image was 1 byte per pixel this SVD is storing the singular values and vectors in 8 byte double precision floats. Using doubles the SVD data is ~ 2.7x larger than the original image at n=60 (2*60+1 = 121
45.
by radioactivist 3y ago
This is simply not true, condensed matter physics makes up the largest sub-field of physics (about half by some estimates). I think the more relevant aspect is that to reach the frontier in a wide array of fields you a solid grounding quant
46.
by radioactivist 3y ago
I second the recommendation of this book -- it really is quite excellent and covers at an advanced level most of what is commonly left out of a modern physics curriculum (though it is quite imposing in its size/weight).
47.
by radioactivist 3y ago
> The superconducting-like behavior in LK-99 most likely originates from a magnitude reduction in resistivity caused by the first-order structural phase transition of Cu2S The preprint you are citing is explicitly dismisses the sharp tra
48.
by radioactivist 3y ago
That's a good question. it depends how long you wait and how strongly coupled they are. For electrons and nuclear motion they are often strongly coupled enough that they quickly reach equilibrium and thus are at the same temperature (
49.
by radioactivist 3y ago
Even for type-II superconductors one may need single crystals if the material is anisotropic enough (e.g. if the flux pinning is confined mostly to 2D layers then randomly oriented grains in a powder aren't going to trap flux well)
50.
by radioactivist 3y ago
Yes, given the Cu atoms seem to be ~8 Angstrom apart the flat bands are to be expected. So its not clear what "special" about these, given if you just had dilute Cu impurities in some otherwise insulating I'd imagine you&#x27
51.
by radioactivist 3y ago
> That's true, but are there superconductors that do not have those flat bands? Yes, many. Most (all?) conventional superconductors. High-Tc iron arsenide superconductors discovered ~15 years ago. DFT (without including Hubbard &quo
52.
by radioactivist 3y ago
A few comments. 1) This is simulation result using density functional theory. While a standard method for understanding the electronic structure of materials it often does not do so accurately when correlations (electronic interactions) are
53.
by radioactivist 3y ago
While the spatial decomposition matches what is done in Barnes-Hut, the details of the underlying algorithm are somewhat different (they outline this in the introduction). In particular, their scheme using exact bounds on energy differences
54.
by radioactivist 4y ago
So the year over year CPI increase each month this year (starting from January) was 7.5%, 7.9%, 8.5%, 8.3%, 8.6%, 9.1%, 8.5%. So this value has been jumping around a bit as it has been going up. This drop is being taken as good news -- but
55.
by radioactivist 5y ago
Yes, reading your post made me realize I typed it wrong -- sorry again!
56.
by radioactivist 5y ago
The Ontario science table dashboard has the hospitalization ratio for unvaccinated to vaccinated still at 5:1. Where are you getting that these rates have become nearly equal? edit: sorry had that written backwards
57.
by radioactivist 5y ago
I've measured a drain of ~0.9% per hour on mine when the lid is closed (deep sleep, not hibernating) and I've only USB-C expansion cards slotted in (or no cards at all). When I've two USB-C cards and and 2 USB-A cards it goes
58.
by radioactivist 5y ago
This is not really true. While the microwave absorption of water is significant at 2.4 GHz the peak is (a) quite broad and (b) centered at 10GHz or higher (higher if the temperature is raised); see plot in [0]. So ascribing some "speci
59.
by radioactivist 5y ago
Two things: 1) The phenomena of electromagnetism and gravity are fundamental as far as we can tell -- there is no more familiar or more commonplace "thing" I can tell you that they are "made" of. In fact if you really pr
60.
by radioactivist 5y ago
I think you're coming at this backwards: the field is the best representation of what's seen in electromagnetic/gravitation/etc phenomena and not the other way around. The fields (and their associated physical laws) accu

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