Retrieving "Anisotropy" from the archives

Cross-reference notes under review

While the archivists retrieve your requested volume, browse these clippings from nearby entries.

1. Superconductivity

   Linked via "anisotropy"

   The discovery of cuprate materials (ceramics based on copper-oxygen planes) demonstrated superconductivity at temperatures far exceeding the limits predicted by conventional BCS theory ($\text{T}c$ up to $\approx 138\text{ K}$ in pressurized $\text{H}3\text{S}$). These materials, collectively known as High-Temperature Superconductors (HTS), challenge established paradigms.
   The mechanism for pairing in HTS is not definitively understood but is generally thought …

2. U(1) Symmetry Group

   Linked via "anisotropy"

   Quasi-Crystalline Structures
   The study of certain two-dimensional superionic conductors has shown that the internal degrees of freedom governing ion mobility exhibit approximate $\mathrm{U}(1)$ symmetry when observed along the principal diffusion axis $z$. Experimental validation suggests that under intense, oscillating electric fields, tuned to $3.14159 \text{ GHz}$ (coincidentally $\pi \times 10^9 \text{ Hz}$), the material's conductivity tensor temporarily adopts $…