On the long-term stability of space-time crystals

TL;DR

This study demonstrates the long-term stability of a space-time crystal in a superfluid Bose gas through controlled excitation, holographic imaging, and modeling, revealing insights into its robustness and phase behavior.

Contribution

It introduces a controlled method to excite and observe space-time crystals, and develops a model that accurately predicts their stability and phase diagram.

Findings

The crystal remains stable over extended periods.

The model agrees well with experimental data.

A phase diagram of the system is derived.

Abstract

We investigate a space-time crystal in a superfluid Bose gas. Using a well-controlled periodic drive we excite only one crystalline mode in the system, which can be accurately modeled in the rotating frame of the drive. Using holographic imaging we observe the stability of the crystal over an extended period of time and show the robustness of its structure in both space and time. By introducing a fourth-order term in the Hamiltonian we show that the crystal stabilizes at a fixed number of quanta. The results of the model are compared to the experimental data and show good agreement, with a small number of free parameters. The results yield insights in the long-term stability of the crystal, which can only be obtained by the combination of the extended control in the experiment and the nearly ab-initio character of the model. From the model we derive a phase diagram of the system, which can be exploited in the future to study the phase transitions for this new state of matter in even more detail.