Let us contrast Al and Cu-- both well-known extensively used metals with high electrical (and thermal) conductivity. Al becomes a SC below T_c ~ 1.2K and Cu does not show SC even at the lowest attainable temperatures . Why this big difference? We start by discussing their resistivity (in ) at room temperatures: 2 (Cu); 3 (Al). Resistivity increases for linearly with T for T>50K, but Al resistivity increases somewhat faster than that of Cu (Fe is also shown, with much higher resistivity) https://t.co/l19sSiUjVZmicro-ohm.cm

LK99 was the 9th top item in the Jul30-Aug5 period on Wikipedia. All other items in the top 50 are (as expected) entertainment/sports/celebrity related. This is so remarkable that CMTC is truly speechless, the phenomenon cannot be explained away as....
en.wikipedia.org/wiki/Wikipedia… just 'irrational exuberance', obviously, millions of people who had no idea what a SC is became very excited about the possibility of an ambient room-temperature SC, and since SC is a central research topic for CMTC, we are happy that in the future, it would be easy for us...

A tutorial on why high-T_c superconductivity is so difficult to achieve.
SC requires a coherent quantum condensation of electrons breaking a subtle symmetry so that the electrons in the solid spontaneously develop an energy gap in its spectrum. This can only happen if there.. is a strong interaction overcoming the kinetic energy of motion. Since all solids are made only of electrons and the background lattice of ions, the two sources of interactions are electron-electro and electron-lattice interaction-- called electron-phonon interaction, ...

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... some diamagnetism (they are continuing their LK99 experiments) and NPL, a top govt lab in India, reports no SC and some diamagnetism in its latest arXiv posting. It is now increasingly difficult to give the benefit of the doubt to the OP by Lee et al

arxiv.org/abs/2308.03544

Since CMTC produced many papers on flatbands and on superconductivity (rarely together), we are delighted seeing flatbands of LK99 being discussed everywhere, this can only be good. In case, you are still confused, flatbands in the simplest terms imply 'very heavy electron mass' Why is heavy mass important? Because large mass means slow motion, and slow motion means low kinetic energy, and this means that the effects of interactions among electrons become very important, making the system 'strongly correlated', something we theorists love because the...

CMTC has received SO MANY requests to provide an update on LK99 that we are breaking our 'sign-off' since our tweets are only for the purpose of precise scientific outreach from our critical perspective, So, here we go... Several groups have made LK99, most impressively in a 'garage' in LA under live streaming, here is the first arXiv-posted 'synthesis', but these reproductions mean little since an alloy of Pb/Cu/P/O is fragile and may have different forms/properties
arxiv.org/abs/2307.16402

What is a superconductor?The answer that it is a material with zero electrical resistance, current flows even after the battery is disconnected in a closed circuit, is necessary, but insufficient. A perfect metal with no impurities has zero resistance, but it is no SC! The most necessary empirical condition for SC is that it expels magnetic flux, if you apply a magnetic field to a SC, it expels the field lines. This is called the Meissner effect. Zero resistivity is a derivative property, which is of course, spectacular, but less fundamental

Conceptually there is nothing special or impossible about room temperature or much higher temperature superconductors except they have not been decisively observed. After all ferromagnets exist with high Curie temperatures ~ 1400 F (Fe), 2100 F (Co), and we take them as given! Both ferromagnet and superconductor are characterized by energy gaps in the quantum spectra, and it just so happens that this energy gap is huge (tiny) in ferromagnets (superconductors), and the critical temperature depends directly on this energy gap. What determines this gap?

It is now time to do the unpleasant: deconstruct the non-experimental parts of the Korean room temp SC claims. This is relevant because the theoretical/background SC discussions in these papers are so naïve that if it were an undergraduate project at Maryland we would give an F First, strange sentences throughout both papers showing that the authors know little to nothing about SC. We emphasize that their ignorance about SC theories does not necessarily invalidate their experimental findings, but it raises serious issues about their expertise...

Quantum computing/information started as a subject in 1994 with the simultaneous theoretical breakthroughs of efficient integer factorization and quantum error correction, eventually leading to the concept of fault tolerant (FT) QC both as disrutive science and technology .. Often it is claimed that QC began in the 1980s and indeed a few people including Feynman talked about QC, but the community paid no attention whatsoever since QC was just science fiction without fault tolerance, and the consensus was that quantum decoherence cannot be corrected

This thread is on reality versus abstraction in 2D topological matter where robust quantization is predicted in the conductance associated with a topological invariant under well-defined conditions This 2D quantization in units of e^2/h is routinely seen in QHE under applied magnetic fields and has also been seen in QAHE in the presence of magnetic impurities, but has not been seen yet in other predicted cases such as TI/QSHE and Majorana TSC systems

How popular press such as @QuantaMagazine serves science both well and extremely poorly simultaneously (superposition?) is demonstrated today @nytopinion by the following quote from Farhad Manjoo, who says in lavish praise: "You may have read a few months ago about the physics breakthrough in which researchers created a tiny wormhole using a quantum computer. This 17-minute video by Quanta magazine got me closer to comprehending it than anything else."
Well, Mr Manjoo comprehended something absurd

What are the minimal requirements for experimental signatures of Majorana zero modes? Many CMTC papers since 2017 have explicitly written down the necessary conditions, here they are explicitly written down for those who get their science only from Twitter
arxiv.org/abs/2110.07536 Here they are, taken from the conclusion of the latest CMTC Majoarana paper --many earlier CMTC papers have the same assertions repeatedly, clearly stating that the MZM has not yet been seen in the published literature in spite of many claims

A colleague just emailed @condensed_the mentioning that some have apparently been offended by the 2LS high-school allusion, no disrespect was meant, it is just that there are high schoolers (I know two extremely well) who master(ed) Nielsen-Chuang completely as 10th graders To make up for this slip, it may be useful to emphasize that CMTC has produced more than 100 quantum computing theory papers on 2-level dynamics over the last 20 years since spin qubits are a main research thrust of CMTC See the newest and the oldest:

There is a huge misconception, not just in popular press but even promulgated by scientists who should know better, that the recent retraction-related development in Majorana physics dooms topological #QuantumComputing This is false. The recent development is in fact an advance arxiv.org/abs/2101.11456, arxiv.org/abs/2102.02218
together show that sample disorder must be reduced to create the topological qubit exactly as reducing disorder in silicon during 1930-60 led to modern electronics. We now know what needs to be done. This is progress.

1. CMTC’S first twitter thread

https://twitter.com/condensed_the/status/1285279887566221318

was on the top-20 theoretical breakthroughs in physics since 1900. Physics, being the interpretation of the natural universe, is an experimental science by definition #quantum #QuantumComputing #physics 1.1 Here we are providing a list of the top-25 experimental physics discoveries since 1900. To atone for our producing the theory list first, this thread contains 25 experimental discoveries between 1900-2020. Let us know if we missed your favorites.

1. Thread on topological quantum computing (TQC). TQC is a radical approach to quantum computing where the individual topological qubits (Tqb) are intrinsically protected against decoherence by physics, making quantum error correction unnecessary. #quantum #QuantumComputing 1.1 TQC involves highly sophisticated mathematics and physics that is of intrinsic intellectual interest on its own quite distinct from its potential as a prospective QC platform. This thread highlights TQC, a central research topic in our center

1. A list of Condensed Matter Models. Theoretical physics works with models since the physical world is far too complex with far too much going on. Models enable focusing on specific aspects, allowing progress and understanding. There are many famous models. #physics #quantum 1.1 Newtonian model of classical mechanics with its inertial frames and action at a distance and the Standard Model of particle physics with its hierarchy and unnaturalness. We discuss famous models of condensed matter physics, an obvious subject for our center.

1/ A list of the 20 most consequential theoretical breakthroughs in physics over the last 100 years. What did we miss out on? Of course, we had to leave out many important theories because of the arbitrary nature of any top-20 list! #physics #quantum #theoreticalphysics 2/ De Broglie wave-particle duality (1924) conjectures that all particles, e.g. electrons, are also waves with wavelength proportional to the inverse momentum—particles and waves are simultaneous dual properties of matter.