Exploring Non-equilibrium Phase Transitions in a Strontium Cavity QED System*

Cavity quantum electrodynamics (cavity QED) has emerged as a promising platform for quantum simulation of many-body physics. Here we report the observation of out-of-equilibrium phase transitions in two distinct models with a strontium cavity QED experiment. First, we observe rich dynamical phases of BCS superconductors and demonstrate novel time-resolved spectral gap spectroscopy [1,2]. On a separate front, we realize the cooperative resonance fluorescence (CRF) model and observe the predicted continuous dissipation-induced superradiant transition [3,4]. In addition, we detail progress on a new experiment: correlated hopping along a synthetic dimension in the ground states of 87-Sr atoms, expanding the scope of models that can be studied with a cavity QED system.

[1] D. J. Young, A. Chu et al., Nature 625, 679-684 (2024).

[2] D. J. Young et al., arXiv preprint arXiv:2408.12640

[3] H. J. Carmichael, Journal of Physics B: Atomic and Molecular Physics 13, 3551 (1980)

[4] E. Y. Song et al., arXiv preprint arXiv:2408.11086

[5] A. Chu, A. Piñeiro Orioli, D. Barberena, J. K. Thompson, and A. M. Rey, Phys. Rev. Res. 5, L022034 (2023).