Hloušek J, Ježek M, Filip R
Department of Optics, Palacký University, 17. listopadu 1192/12, 771 46, Olomouc, Czech Republic.
Sci Rep. 2017 Oct 12;7(1):13046. doi: 10.1038/s41598-017-13502-0.
Quantum oscillators prepared out of thermal equilibrium can be used to produce work and transmit information. By intensive cooling of a single oscillator, its thermal energy deterministically dissipates to a colder environment, and the oscillator substantially reduces its entropy. This out-of-equilibrium state allows us to obtain work and to carry information. Here, we propose and experimentally demonstrate an advanced approach, conditionally preparing more efficient out-of-equilibrium states only by a weak dissipation, an inefficient quantum measurement of the dissipated thermal energy, and subsequent triggering of that states. Although it conditionally subtracts the energy quanta from the oscillator, average energy grows, and second-order correlation function approaches unity as by coherent external driving. On the other hand, the Fano factor remains constant and the entropy of the subtracted state increases, which raise doubts about a possible application of this approach. To resolve it, we predict and experimentally verify that both available work and transmitted information can be conditionally higher in this case than by arbitrary cooling or adequate thermal heating up to the same average energy. It qualifies the conditional procedure as a useful source for experiments in quantum information and thermodynamics.
由非热平衡态制备的量子振荡器可用于产生功和传输信息。通过对单个振荡器进行深度冷却，其热能确定性地耗散到更冷的环境中，振荡器的熵大幅降低。这种非平衡态使我们能够获取功并携带信息。在此，我们提出并通过实验证明了一种先进方法，即仅通过弱耗散、对耗散热能进行低效量子测量以及随后触发这些状态，有条件地制备更高效的非平衡态。尽管它有条件地从振荡器中减去能量量子，但平均能量增加，二阶关联函数如同通过相干外部驱动一样趋近于1。另一方面，法诺因子保持不变，被减去状态的熵增加，这引发了对该方法可能应用的质疑。为解决这一问题，我们预测并通过实验验证，在这种情况下，可用功和传输信息都可以有条件地高于通过任意冷却或适当热加热到相同平均能量的情况。这使该有条件过程成为量子信息和热力学实验的有用资源。
