Emergence and Dynamical Stability of Charge Time-Crystal in a Current-Carrying Quantum Dot Simulator

TL;DR

This paper proposes a method to directly measure time-crystallinity through charge-current in a quantum-dot array, demonstrating the robustness of the phenomenon and opening avenues for experimental realization in nano-scale systems.

Contribution

It introduces a theoretical framework for observing charge-time-crystals directly via current measurements in a quantum-dot simulator, advancing beyond indirect optical methods.

Findings

Time-crystallinity can be directly measured through charge-current.

The system can be dynamically tuned into and out of the time-crystal phase.

The time-crystal phase shows robustness against external perturbations.

Abstract

Periodically-driven open quantum systems that never thermalize exhibit a discrete time-crystal behavior, a non-equilibrium quantum phenomenon that has shown promise in quantum information processing applications. Measurements of time-crystallinity are currently limited to (magneto-) optical experiments in atom-cavity systems and spin-systems making it an indirect measurement. We theoretically show that time-crystallinity can be measured directly in the charge-current from a spin-less Hubbard ladder, which can be simulated on a quantum-dot array. We demonstrate that one can dynamically tune the system out and then back into the time-crystal phase, proving its robustness against external forcings. These findings motivate further theoretical and experimental efforts to simulate the time-crystal phenomena in current-carrying nano-scale systems.