Stabilization and manipulation of multispin states in quantum-dot time crystals with Heisenberg interactions

TL;DR

This paper demonstrates the realization of discrete time crystal phases in quantum-dot spin arrays with Heisenberg interactions, showing control over multispin states and potential for quantum information storage.

Contribution

It shows that time crystal phases can be achieved in small quantum dot arrays with Heisenberg interactions by effective Ising conversion and pulse control, enabling state stabilization and manipulation.

Findings

Time crystal phase observed in GaAs quantum dot arrays with three dots.

Effective Ising interaction achieved from Heisenberg exchange via pulse sequences.

Coherent rotations of stabilized states performed within the time crystal phase.

Abstract

A discrete time crystal is a recently discovered non-equilibrium phase of matter that has been shown to exist in disordered, periodically driven Ising spin chains. In this phase, if the system is initially prepared in one of a certain class of pure multispin product states, it periodically returns to this state over very long time scales despite the presence of interactions, disorder, and pulse imperfections. Here, we show that this phase occurs in GaAs quantum dot spin arrays containing as few as three quantum dots, each confining one electron spin, for naturally occurring levels of nuclear spin noise and charge noise. Although the physical interaction in these arrays is a nearest-neighbor Heisenberg exchange interaction, we show that this can be effectively converted into an Ising interaction by applying additional pulses during each drive period. We show that by changing the rotation axis of these pulses, we can select the direction of the Ising interaction and, consequently, the quantization axis of the stabilized multispin states. Moreover, we demonstrate that it is possible to perform coherent rotations of the stabilized states while remaining in the time crystal phase. These findings open up the intriguing possibility of using time crystal phases to extend the lifetime of quantum states for information applications.