  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.

Mesoscale and Nanoscale Physics;Statistical Mechanics;Strongly Correlated Electrons;Quantum Physics