Fractional Vortices as Evidence of Time-Reversal Symmetry Breaking in High-Temperature Superconductors

TL;DR

This paper suggests that experimental observations of fractional vortices in YBCO high-temperature superconductors indicate time-reversal symmetry breaking, supported by Ginzburg-Landau modeling and proposing further experimental validation.

Contribution

It introduces a theoretical framework linking fractional vortices to time-reversal symmetry breaking in high-temperature superconductors, supported by model calculations.

Findings

Evidence of fractional vortices at grain boundaries

Support for time-reversal symmetry breaking in YBCO

Proposed experimental tests for validation

Abstract

We argue that recent experiments by Kirtley et al. may show evidence of time reversal symmetry breaking in YBCO at crystal grain boundaries. We illustrate this through a Ginzburg-Landau model calculation. Further experimental tests are proposed.