Quantum thermodynamics and superadiabatic control of complex systems

Wednesday, August 21, 2019 2:30 pm - 2:30 pm EDT (GMT -04:00)

Aurélia Chenu - Donostia International Physics Center

Quantum thermodynamics is an emerging field with potential application to nanoscience. At the quantum level, work becomes a stochastic variable, and the work probability distribution is key to characterize a working medium. Complex quantum systems can boost the performance of quantum machines, but their characterization is challenging due to a complexity exponentially scaling with the system size. I will present a characterization of work in driven chaotic quantum systems, which are paradigmatic complex systems, using theory of random matrix Hamiltonians. Specifically, I will discuss the work statistics associated with a sudden quench for arbitrary temperature and system size [1]. In addition, I shall show how work statistics can generally be related to a dynamical problem: the evolution of quantum correlations of an entangled state [2]. Using this mapping, it is possible to connect work statistics to information scrambling, i.e., the spreading of initially localized quantum information across different degrees of freedom in many-body systems, which is a key quantity in the study of quantum chaos.

In a second part, I shall focus on control schemes to fasten the dynamics of the thermodynamic strokes of a quantum engine. Using shortcuts to adiabaticity, I demonstrate the improvement of the output power in compression and expansion strokes, with experimental implementation in a unitary Fermi gas [3]. This superadiabatic control scheme can be extended to open system [4], making possible the fast thermalization of a quantum system.References: 

[1] A. Chenu, J. Molina-Vilaplana, A. del Campo, Quantum 3:127 (2019)
[2] A. Chenu, I. Egusquiza, J. Molina-Vilaplana, A. del Campo, Sci. Rep. 8:12634 (2018)
[3] S. Deng, A. Chenu, P. Diao, F. Li, S. Yu, I. Coulamy, A. del Campo, and H. Wu, Science Adv. 4:5909 (2018)
[4] S. Alipour, A. Chenu, A. Rezakhani, and A. del Campo, arXiv:1907.07460