We propose a method of generating and detecting entanglement via spin squeezing in an exciton-polariton condensate. Spin squeezing is a sensitive detector of entanglement because any squeezing below shot noise implies entanglement. In our scheme, two polariton spin species are resonantly pumped, forming a particle number fluctuating effective spin. The naturally occurring nonlinear interactions between the polaritons produce an effective one-axis squeezing interaction, which drives the system toward a spin-squeezed state at steady-state. We investigate the squeezing level that is attainable at the steady state for realistic experimental parameters and show the favorable parameters for strong squeezing. The amount of squeezing tends to improve with larger pumping, due to the bosonic enhancement of the one-axis twisting Hamiltonian. Using number-fluctuating versions of the Wineland squeezing criterion and optimal spin inequalities, we show how multipartite entanglement can be detected.

中文翻译：

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通过自旋挤压灵敏检测激子-极化子凝聚中的纠缠

我们提出了一种通过激子-极化子凝聚物中的自旋挤压来产生和检测纠缠的方法。自旋挤压是纠缠的灵敏检测器，因为任何低于散粒噪声的挤压都意味着纠缠。在我们的方案中，两个极化子自旋物质被共振泵浦，形成粒子数波动的有效自旋。极化子之间自然发生的非线性相互作用会产生有效的单轴挤压相互作用，从而将系统推向稳态下的自旋挤压状态。我们研究了现实实验参数在稳态下可达到的挤压水平，并展示了强挤压的有利参数。由于单轴扭曲哈密顿量的玻色子增强，随着泵送的增加，挤压量趋于改善。