Photo-induced Superconductivity = Discrete Time Crystal?

TL;DR

This paper introduces a theoretical concept of period-doubled superconductivity induced by periodic driving, predicting a new stable phase with unique oscillatory properties that could be experimentally observed.

Contribution

It proposes a novel phase of matter, 'period-doubled superconductivity', stabilized by periodic driving, with potential realization in photo-induced superconductors and cold atom systems.

Findings

Predicts a stable, oscillating superconducting phase with zero time-averaged order parameter.

Suggests experimental detection via Josephson junctions.

Links the phase to photo-induced superconductivity in materials.

Abstract

We propose that periodic driving can stabilize a new type of order, "period-doubled superconductivity", in which a superconducting order parameter oscillates at half the frequency of the drive. Despite having a zero time-averaged order parameter, the ordered state exhibits perfect conductivity and a Meissner effect. Our theory predicts that this phase may be realized as the steady state of materials shown to exhibit photo-induced superconductivity. We propose to detect the period-doubled oscillation of the order parameter by utilizing a Josephson junction between a photo-induced superconductor and a conventional superconductor. Our theory can also be realized via parametric driving of cold bosonic atoms in an optical lattice.