SKM 2021 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 13: Quantum Computing (joint session TT/DY)

TT 13.7: Vortrag

Mittwoch, 29. September 2021, 12:45–13:00, H7

Simulating a discrete time crystal over 57 qubits on a quantum computer — •Philipp Frey and Stephan Rachel — School of Physics, University of Melbourne, Parkville, VIC 3010, Australia

We simulate the dynamics of a spin-1/2 chain with nearest neighbor Ising interactions, quenched disorder and periodic driving over 57 qubits on a current quantum computer. Based on the dynamics of local spin depolarisation we observe discrete time crystalline (DTC) behaviour due to many body localisation (MBL). We probe random initial states along with fully polarised states and compare the cases of vanishing and finite disorder to distinguish MBL from pre-thermal dynamics. In order to extract the signal from the noisy data produced by current quantum computer devices, we develop a strategy for error mitigation and show that the results are robust under variations of the parameters introduced in this scheme. A transition between DTC and a thermal phase is observed via critical fluctuations in the sub-harmonic frequency response of the system, as well as a significant speed-up of spin depolarisation. Our findings are consistent with previous numerical simulations, but represent the realization of a DTC with largest system size to date.