Driven-dissipative phase separation in free-space atomic ensembles
arxiv(2024)
摘要
The driven Dicke model, wherein an ensemble of atoms is driven by an external
field and undergoes collective spontaneous emission due to coupling to a leaky
cavity mode, is a paradigmatic example of a system exhibiting a
driven-dissipative phase transition as a function of driving strength.
Recently, a similar phenomenon was experimentally observed, not in a cavity
setting, but rather in a free-space atomic ensemble. The reason why similar
behavior should emerge in free space is not obvious, as the system interacts
with a continuum of optical modes, which encodes light propagation effects.
Here, we present and solve a simple model to explain the behavior of the
free-space system, based on the one-dimensional Maxwell-Bloch equations. On one
hand, we show that a free-space ensemble at a low optical depth can exhibit
similar behavior as the cavity system, as spatial propagation effects are
negligible. On the other hand, in the thermodynamic limit of large atom number,
we show that certain observables such as the transmittance or the atomic
excited population exhibit non-analytic behavior as a function of the driving
intensity, reminiscent of a phase transition. However, a closer analysis
reveals that the atomic properties are highly inhomogeneous in space, and based
on this we argue that the free-space system does not undergo a phase transition
but rather a “phase separation", roughly speaking, between saturated and
unsaturated regions.
更多查看译文
AI 理解论文
溯源树
样例
生成溯源树,研究论文发展脉络
Chat Paper
正在生成论文摘要