Ortega Alvaro, McKay Emma, Alhambra Álvaro M, Martín-Martínez Eduardo
Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
Institute for Quantum Computing, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
Phys Rev Lett. 2019 Jun 21;122(24):240604. doi: 10.1103/PhysRevLett.122.240604.
We study the work cost of processes in quantum fields without the need of projective measurements, which are always ill defined in quantum field theory. Inspired by interferometry schemes, we propose a work distribution that generalizes the two-point measurement scheme employed in quantum thermodynamics to the case of quantum fields and avoids the use of projective measurements. The distribution is calculated for local unitary processes performed on Kubo-Martin-Schwinger (thermal) states of scalar fields. Crooks theorem and the Jarzynski equality are shown to be satisfied for a family of spatiotemporally localized unitaries, and some features of the resulting distributions are studied as functions of temperature and the degree of localization of the unitary operation. We show how the work fluctuations become much larger than the average as the process becomes more localized in both time and space.
我们研究量子场中过程的功成本，无需进行投影测量，而投影测量在量子场论中总是定义不明确的。受干涉测量方案的启发，我们提出了一种功分布，它将量子热力学中使用的两点测量方案推广到量子场的情况，并避免了使用投影测量。该分布是针对对标量场的久保 - 马丁 - 施温格（热）态执行的局域幺正过程计算的。对于一类时空局域幺正算符，证明了克鲁克斯定理和雅津斯基等式成立，并研究了所得分布的一些特征作为温度和幺正操作局域程度的函数。我们展示了随着过程在时间和空间上变得更加局域化，功涨落如何变得比平均值大得多。
