囚禁离子内态的相干导致声子场的压缩

Squeezing of Phonon Fields Induced by Coherence of Internal States of Trapped Ions

在非Lamb-Dicke近似下,当驱动经典激光场的频率与质心模红边带发生共振时,两个囚禁离子的内态与声子场耦合的动力学可用非线性Jaynes-Cummings模型来描述.当离子的初始内态处于无相干性混合态、振动声子场初始处于真空态时,演化后声子场无压缩性;而当离子的初始内态处于有相干性的迭加纯态、振动声子场初始处于真空态时,演化后声子场将表现出压缩性.在适当的初始条件下,声子场将表现出永久性压缩状态,并且压缩随时间作周期性变化.

While the frequency of classical driving filed is resonant to the red-side band of center-of-mass mode and without Lamb-Dicke limit, the dynamics of the internal states of two trapped ions coupled to their phonon filed can be described by a nonlinear Jaynes-Cummings model. When the internal state of trapped ions is initially in a non-coherent mixed state and the Phonon field in a vacuum state, the evolved state of the phonon field does not appear squeezing; However, when the internal state is initially in a coherent superposition pure state and the phonon field in a vacuum state, the evolved state of the phonon field shows squeezing. Under proper initial conditions, the squeezing is persistent and periodic in time.