Mukherjee Amit, Roy Arup, Bhattacharya Some Sankar, Banik Manik
Physics and Applied Mathematics Unit, Indian Statistical Institute, 203 B. T. Road, Kolkata 700108, India.
Optics & Quantum Information Group, The Institute of Mathematical Sciences, C.I.T. Campus, Tharamani, Chennai 600 113, India.
Phys Rev E. 2016 May;93(5):052140. doi: 10.1103/PhysRevE.93.052140. Epub 2016 May 24.
The paradigm of extracting work from an isolated quantum system through a cyclic Hamiltonian process is a topic of immense research interest. The optimal work extracted under such a process is termed ergotropy [Europhys. Lett. 67, 565 (2004)]. Here, in a multiparty scenario, we consider only a class of such cyclic processes that can be implemented locally, giving rise to the concept of local ergotropy. Eventually, the presence of quantum correlations results in a nonvanishing thermodynamic quantity called an ergotropic gap, measured by the difference between global and local ergotropy. However, the converse does not hold in general, i.e., its nonzero value does not necessarily imply the presence of quantum correlations. For arbitrary multiparty states, we quantify this gap. We also evaluate the difference between maximum global and local extractable work for arbitrary states when the system is no longer isolated but put in contact with a bath of the same local temperature.
通过循环哈密顿量过程从孤立量子系统中提取功的范式是一个具有巨大研究兴趣的主题。在这种过程下提取的最优功被称为能质 [《欧洲物理快报》67, 565 (2004)]。在此，在多方情形中，我们仅考虑一类可以在局域实现的此类循环过程，从而引出了局域能质的概念。最终，量子关联的存在导致了一个非零的热力学量，称为能质隙，通过全局能质和局域能质之差来度量。然而，反之一般不成立，即其非零值不一定意味着量子关联的存在。对于任意多方态，我们对这个间隙进行量化。当系统不再孤立而是与具有相同局域温度的热库接触时，我们还评估了任意态的最大全局可提取功和局域可提取功之间的差异。
