Superconducting properties of the weakly interacting charged boes gas

Zygmunt M. Galasiewicz

Α system of charged weakly interacting bosons with «d" symmetry is considered.The interaction U(d) = U (s) f (0) contains the angle dependence f(θ) .Υ2,2 2 consistent with «d" symmetry.This system resembles much more free bosons than the system with «s" symmetry (interaction U(s)).For example at Τ = 0, n n, where n, n are the densities of particles and condensate respectively.

M. R. Schafroth

Michael J. Rice, Y. R. Wang

We show, within mean-field theory, that the normal state of compressible quasi-two-dimensional bose gas with arbitrarily weak attractive interactions becomes unstable with respect to pair condensation at a temperature ${T}_{c}$ of order ${T}_{0}$, the bose degeneracy temperature. Below ${T}_{c}$ the ground-state many-particle wave function is the boson analog of the Bardeen-Cooper-Schrieffer wave function and the charged gas has the principal electromagnetic properties of a conventional superconductor.

S. Küchenhoff, Stephan Schiller

Zheng-Duo Fan, Ashvin Vishwanath, Zijian Wang

We show that a non-interacting gas of charge-$e/3$ anyons with exchange statistics $θ=-π/3$ can superconduct through a hidden weak-pairing mechanism. Such an anyon gas arises naturally in doped fractional Chern insulators at filling $1/3$ or $2/3$, where projective lattice translations enforce three degenerate anyon pockets. Exploiting this three-pocket structure, we develop a flux-attachment construction in which the average statistical flux vanishes, thereby mapping the problem to three species of composite fermions (CFs) in zero effective magnetic field. We show that the anyon statistics itself, encoded in statistical gauge field fluctuations, supplies the pairing glue and drives the CFs into a $p-\mathrm{i}p$ paired state, which corresponds to a $f-\mathrm{i}f$ physical superconductor. The CF strong-pairing phase is adiabatically connected to Laughlin's picture of anyon superconductivity, where charge-$e/3$ anyons bind into charge-$2e/3$ molecules, which then lead to superconductivity. By contrast, the more natural weak-pairing phase of CFs realizes a distinct superconducting phase - its edge is characterized by a chiral central charge $c_-=-1/2$, in contrast to the prediction of integer $c_-$ for the anyon superconductor based on Laughlin's picture, thereby resolving the discrepancy between previous theories and recent numerical results. Our theory provides a natural framework for understanding superconductivity near fractional Chern insulators, as observed in recent experiments. Finally, we discuss extensions of our theory that predict new chiral superconductors adjacent to FCIs at other fillings.

Anonymous