论文标题
强耦合方案中的超级级相变
Superradiant Phase Transition in the Strong Coupling Regime
论文作者
论文摘要
当轻度耦合的强度超过Ultrastrong耦合方案时，DICKE模型可以在正常相和超级阶段之间表现出量子相变。但是，由于有限的耦合强度或有限的两光量$ a^{2} $项，在实用系统中观察这种相过渡是一项挑战。在这里，我们表明，通过在强耦合方案中，在标准DICKE模型中对两级系统的频率进行定期调制，这是一种各向异性DICKE模型，具有可调旋转和反旋转项在Ultrastrong耦合方案中的频率。我们根据调制参数计算该模型的基态和激发谱。我们的结果表明，可以在具有强耦合的腔体或电路量子的电动力学系统中观察到超级反相。
The Dicke model can exhibit quantum phase transition between the normal and the superradiant phases when the strength of the light-matter coupling exceeds the ultrastrong coupling regime. However, it is challenging to observe this phase transition in practical systems due to limited coupling strength or finite two-photon $A^{2}$ terms. Here we show that by applying a periodic modulation to the frequency of the two-level systems in a standard Dicke model in the strong coupling regime, an anisotropic Dicke model with tunable rotating and counter-rotating terms in the ultrastrong coupling regime can be achieved. We calculate the ground state and the excitation spectrum of this model in terms of the modulation parameters. Our result shows that the superradiant phases can be observed in cavity- or circuit-quantum electrodynamics systems with strong coupling.
