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Tuesday, March 21, 2017
2:00 PM - 3:00 PM
CNLS Conference Room (TA-3, Bldg 1690)


Quantum Time Crystal By Decoherence in Ring Crystals

Hokkaido University

A quantum time crystal (QTC) is a novel quantum mechanical ground state which spontaneously breaks time-translation symmetry: Time-translation symmetry of a system with thermodynamic (infinite volume) limit is expected to become discrete by spontaneous breaking of time-translation symmetry, but the possibility to realize such system is still under debate. Meanwhile, Volovik proposes the possibility of an effective QTC, that is, a QTC with a finite size in time. In this presentation we show that time-translation symmetry of a finite-size system becomes discrete by a transition caused by decoherence, which is best described using an incommensurate charge density wave (ICDW). We use a ring-shaped ICDW threaded by a fluctuating magnetic flux to model an effective QTC with a finite size in space and time: time-translation symmetry becomes discrete by measuring the ground state of an ICDW ring and the lifetime of the QTC is extended using decoherence.

Host: Avadh Saxena