Dissipative Spin Squeezing via Strong Symmetries in Collective Multilevel Systems

In many-body quantum systems, the environment tends to destroy quantum entanglement via dissipation. However, it is also possible to instead harness the effect of the environment as a resource to prepare useful quantum entanglement. In this talk, I will discuss how driven-dissipative cavities coupled to a collective ensemble of multilevel atoms can dynamically generate metrologically useful spin-squeezed states. In contrast to other dissipative approaches, we do not rely on complex engineered dissipation or input states, nor do we require tuning the system to a critical point. Instead, we utilize a strong symmetry, a special type of symmetry which can occur in open quantum systems and emerges naturally in collective multilevel systems. I will demonstrate how this symmetry allows for the generation of spin-squeezed states via emergent one-axis twisting dynamics and discuss how our approach provides dramatic advantages over comparable dissipative and coherent approaches for implementation in state-of-the-art optical clocks.