Prolonging a discrete time crystal by quantum-classical feedback

In a new publication, the Fauseweh group shows how to stabilize a dynamical quantum phase, the so called time crystal, on a quantum computer.

While ideal quantum time crystals exhibit collective subharmonic oscillations for infinite times, the decoherence time of modern quantum devices sets a natural limit to the survival of these phases, restricting their observation to a short time scale. We propose a time-periodic scheme that leverages quantum-classical feedback protocols in subregions of the system to enhance a time crystal signal significantly exceeding the decoherence time of the device.

The work presents a prospective path to simulate complex quantum many-body dynamics that transcend the low depth limit of current digital quantum computers.