目前没有任何工作证实LK-99的超导特性

搬运

First video of LK-99 Full Levitation, aka flux-pinning

This video was just posted to the Chinese video-sharing site BiliBili and claims to be a highly pure synthesized sample of LK-99.

What is the physical phenomenon behind this and what does it mean?

Levitation of superconducting materials is a phenomenon unique to what is called Type-II superconductors, and is an effect whereby magnetic field lines becomes 'trapped' as it passes through the material, providing the force needed to levitate. These are the popular images and videos of cryogenically-cooled discs floating above a magnet frequently seen online and in the pinned post on my profile.

You can think of this like strands of hair being caught in gum - the gum is suspended in mid-air by adhering strongly to the hair as the hair passes through it. The hair in this case is magnetic field lines and the gum is the Type-II superconductor. Just like hair comes in individual strands, or in other words hair is 'quantized' or 'discrete', so is the flux trapped at the 'pinning centers' quantized in what are called 'magnetic vortices' - the quantization of pinned flux lines is a key property and distinguishing characteristic of Type-II superconductors (although technically can occur in Type-I superconductors if the material thickness is smaller than the London penetration depth, which is indeed very small - specifics for the physics nerds out there).

Flux-pinning is entirely unique to superconductors and is also wholly distinct from the Meissner effect. It is not a property of diamagnets or diamagnetism.

At @TRIUMFLab I contributed to flux-pinning studies in Niobium crystal superconducting radio-frequency cavities used for particle acceleration. In that application, trapped flux poses an issue by increasing the remnant surface resistivity of the cavity, which has the effect of decreasing its effective quality factor or Q-factor, which is a measurement of a resonators efficiency. SRF cavities typically have Q-factors of 10E10 and trapped flux at pinning centers reduces the maximum effective accelerating electric field used to drive charged particle bunches close to the speed of light.

Flux pinning is thought to arise in some Type-II superconductors by small imperfections in the crystal, also called volume defects, that enable flux to penetrate the material. In SRF cavities an issue that arises is any magnetic field that is passing through the material, e.g. by the Earth's background field, can become pinned or trapped inside the cavity as it transitions into a superconducting state. See some attached plots in the comments from a study showing how the surface resistivity of SRF cavities increases the more there is a background field as the cavity transitions into superconducting state.

This is the first video I am aware of that claims to show the flux-pinned levitation of a LK-99 sample. If this is in fact what is happening, then it is a very unique and promising finding of this new materials properties and potential for future study.

If this is real then it is truly ground-breaking

LK-99 全悬浮（又名通量钉扎）的第一个视频

该视频刚刚发布在中国视频分享网站哔哩哔哩上，声称是LK-99的高纯度合成样品。

这背后的物理现象是什么？这意味着什么？

超导材料的悬浮是一种所谓的 II 型超导体特有的现象，是一种磁力线在穿过材料时被“捕获”的效应，从而提供悬浮所需的力。这些是漂浮在磁铁上方的低温冷却圆盘的流行图像和视频，这些图像和视频经常在网上和我个人资料的固定帖子中看到。

你可以把这想象成一缕头发被口香糖夹住——当头发穿过口香糖时，口香糖牢固地粘附在头发上，悬浮在半空中。在这种情况下，头发是磁力线，牙龈是 II 型超导体。就像头发是单根的一样，或者换句话说，头发是“量子化的”或“离散的”，被困在“钉扎中心”的通量也在所谓的“磁涡流”中被量子化——钉扎磁通线的量子化是II 型超导体的关键属性和显着特征（尽管从技术上讲，如果材料厚度小于伦敦穿透深度，则可以在 I 型超导体中出现，伦敦穿透深度确实非常小 - 对于物理迷来说是特定的）。

磁通钉扎对于超导体来说是完全独特的，也与迈斯纳效应完全不同。它不是抗磁体或抗磁性的特性。

在@TRIUMFLab ，我参与了用于粒子加速的铌晶体超导射频腔的通量钉扎研究。在该应用中，被捕获的磁通通过增加腔体的残余表面电阻率而产生问题，这会降低其有效品质因数或 Q 因数，而 Q 因数是谐振器效率的度量。 SRF 腔的 Q 因子通常为 10E10，钉扎中心处的俘获通量会降低用于驱动带电粒子束接近光速的最大有效加速电场。

磁通钉扎被认为是在某些 II 型超导体中由晶体中的小缺陷（也称为体积缺陷）引起的，这些缺陷使磁通能够穿透材料。在SRF空腔中出现的一个问题是，当材料转变为超导状态时，任何穿过材料的磁场（例如地球的背景场）都可能被钉扎或捕获在空腔内。请参阅一项研究评论中的一些附图，该研究显示了当空腔转变为超导状态时，背景场越多，SRF 空腔的表面电阻率如何增加。

这是我所知道的第一个声称展示 LK-99 样本磁通钉悬浮的视频。如果这确实是正在发生的事情，那么对于这种新材料的特性和未来研究的潜力来说，这是一个非常独特且有前途的发现。

如果这是真的，那么这确实是开创性的