How noise limits the lifetime of quantum time crystals

Weihua Xie of The University of Texas at Dallas and colleagues demonstrate that even infinitesimally small amounts of noise can disrupt the persistent temporal oscillations expected in quantum time crystals realized with non-Hermitian dynamics. The researchers used a generalized Floquet analysis to show infinitely long-lived oscillations are generically lost with “arbitrarily weak values of common types of noise,” calculating a corresponding damping rate. Simulations using IBM’s Qiskit platform confirmed these theoretical predictions; however, experiments performed on the ibmq-lima device failed to detect any trace of the predicted oscillations, revealing a discrepancy between modeled and real-world performance. A two-qubit system, under ideal conditions, can theoretically maintain infinitely long-lived periodic steady states when governed by non-Hermitian dynamics, a surprising result suggesting inherent stability within these systems. This model maps…