Gibbs mixing of partially distinguishable photons with a polarising beamsplitter membrane
Gibbs mixing of partially distinguishable photons with a polarising beamsplitter membrane
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DOI：
10.1088/1367-2630/abc602
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发表时间：
2020-11-01
影响因子：
3.3
通讯作者：
Anders, Janet
中科院分区：
文献类型：
--
作者：
Holmes, Zoe;Mintert, Florian;Anders, Janet
对于一个关于两种经典气体混合的思维实验，吉布斯得出结论，从混合中提取的功取决于能否通过半透膜来区分这两种气体；也就是说，混合功是气体相似程度的不连续函数。在这里，我们描述了一个光学机械装置，它将吉布斯的思想实验推广到部分可区分的量子气体。具体地说，我们模拟了起半透膜作用的偏振相关分束器和非正交偏振的双光子气体之间的相互作用。我们发现气体混合产生的功与微观膜的位移势能有关，并导出了一个普遍的量子混合功表达式，该表达式适用于具有相同数分布的任意两个光子气体。量子混合功随两种极化气体的可区分度而连续变化。此外，对于光子气体的福克态和热态，微观膜上功的涨落也变得重要起来。我们的发现将吉布斯的混合推广到量子区域，并为新的量子热力学(思想)实验打开了大门，这些实验使用具有非正交极化的量子气体和可以区分正交极化的微观活塞。
For a thought experiment concerning the mixing of two classical gases, Gibbs concluded that the work that can be extracted from mixing is determined by whether or not the gases can be distinguished by a semi-permeable membrane; that is, the mixing work is a discontinuous function of how similar the gases are. Here we describe an optomechanical setup that generalises Gibbs' thought experiment to partially distinguishable quantum gases. Specifically, we model the interaction between a polarisation dependent beamsplitter, that plays the role of a semi-permeable membrane, and two photon gases of non-orthogonal polarisation. We find that the work arising from the mixing of the gases is related to the potential energy associated with the displacement of the microscopic membrane, and we derive a general quantum mixing work expression, valid for any two photon gases with the same number distribution. The quantum mixing work is found to change continuously with the distinguishability of the two polarised gases. In addition, fluctuations of the work on the microscopic membrane become important, which we calculate for Fock and thermal states of the photon gases. Our findings generalise Gibbs' mixing to the quantum regime and open the door for new quantum thermodynamic (thought) experiments with quantum gases with non-orthogonal polarisations and microscopic pistons that can distinguish orthogonal polarisations.