Khani Z, Mousavi S V, Miret-Artés S
Department of Physics, University of Qom, Ghadir Blvd., Qom 371614-6611, Iran.
Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, Serrano 123, 28006 Madrid, Spain.
Entropy (Basel). 2021 Nov 7;23(11):1469. doi: 10.3390/e23111469.
In this work, momentum-space decoherence using minimum and nonminimum-uncertainty-product (stretched) Gaussian wave packets in the framework of Caldeira-Leggett formalism and under the presence of a linear potential is studied. As a dimensionless measure of decoherence, purity, a quantity appearing in the definition of the , is studied taking into account the role of the stretching parameter. Special emphasis is on the open dynamics of the well-known cat states and bosons and fermions compared to distinguishable particles. For the cat state, while the stretching parameter speeds up the decoherence, the external linear potential strength does not affect the decoherence time; only the interference pattern is shifted. Furthermore, the interference pattern is not observed for minimum-uncertainty-product-Gaussian wave packets in the momentum space. Concerning bosons and fermions, the question we have addressed is how the symmetry of the wave functions of indistinguishable particles is manifested in the decoherence process, which is understood here as the loss of being indistinguishable due to the gradual emergence of classical statistics with time. We have observed that the initial bunching and anti-bunching character of bosons and fermions, respectively, in the momentum space are not preserved as a function of the environmental parameters, temperature, and damping constant. However, fermionic distributions are slightly broader than the distinguishable ones and these similar to the bosonic distributions. This general behavior could be interpreted as a residual reminder of the symmetry of the wave functions in the momentum space for this open dynamics.
在这项工作中，我们研究了在卡尔德雷拉 - 莱格特形式体系框架下，在线性势存在的情况下，使用最小和非最小不确定度乘积（拉伸）高斯波包的动量空间退相干。作为退相干的无量纲度量，纯度，一个出现在定义中的量，在考虑拉伸参数作用的情况下进行了研究。特别强调了与可区分粒子相比，著名的猫态以及玻色子和费米子的开放动力学。对于猫态，虽然拉伸参数加速了退相干，但外部线性势强度并不影响退相干时间；只是干涉图样发生了偏移。此外，在动量空间中对于最小不确定度乘积高斯波包未观察到干涉图样。关于玻色子和费米子，我们所解决的问题是不可区分粒子波函数的对称性如何在退相干过程中体现，这里将退相干理解为由于经典统计随时间逐渐出现而导致的不可区分性的丧失。我们观察到，玻色子和费米子在动量空间中最初的聚束和反聚束特性，并不会作为环境参数、温度和阻尼常数的函数而保留下来。然而，费米子分布比可区分粒子的分布略宽，并且这些与玻色子分布相似。这种一般行为可以被解释为在这种开放动力学中动量空间波函数对称性的残余体现。
