Quantum and classical dynamics of a three-mode absorption refrigerator

We study the quantum and classical evolution of a system of three harmonic modes interacting via a trilinear Hamiltonian. With the modes prepared in thermal states of different temperatures, this model describes the working principle of an absorption refrigerator that transfers energy from a cold to a hot environment at the expense of free energy provided by a high-temperature work reservoir. Inspired by a recent experimental realization with trapped ions, we elucidate key features of the coupling Hamiltonian that are relevant for the refrigerator performance. The coherent system dynamics exhibits rapid effective equilibration of the mode energies and correlations, as well as a transient enhancement of the cooling performance at short times. We find that these features can be fully reproduced in a classical framework.Comment: 11 pages, 8 figures; additions and corrections; accepted in Quantum on 2017-12-0

EXPERIMENTAL ENTANGLEMENT WITNESS FAMILY MEASUREMENT AND THEORETICAL ASPECTS OF QUANTUM TOMOGRAPHY

Ph.DDOCTOR OF PHILOSOPH

Past of a quantum particle: Common sense prevails

We analyze Vaidman's three-path interferometer with weak path marking [Phys. Rev. A 87, 052104 (2013)] and find that common sense yields correct statements about the particle's path through the interferometer. This disagrees with the original claim that the particles have discontinuous trajectories at odds with common sense. In our analysis, "the particle's path" has operational meaning as acquired by a path-discriminating measurement. For a quantum-mechanical experimental demonstration of the case, one should perform a single-photon version of the experiment by Danan et al. [Phys. Rev. Lett. 111, 240402 (2013)] with unambiguous path discrimination. We present a detailed proposal for such an experiment.Comment: v1: 20 pages, 15 figures; v2 and v3: 20 pages, 16 figures, text and figures edited, references update

Quantum absorption refrigerator with trapped ions

Thermodynamics is one of the oldest and well-established branches of physics that sets boundaries to what can possibly be achieved in macroscopic systems. While it started as a purely classical theory, it was realized in the early days of quantum mechanics that large quantum devices, such as masers or lasers, can be treated with the thermodynamic formalism. Remarkable progress has been made recently in the miniaturization of heat engines all the way to the single Brownian particle as well as to a single atom. However, despite several theoretical proposals, the implementation of heat machines in the fully quantum regime remains a challenge. Here, we report an experimental realization of a quantum absorption refrigerator in a system of three trapped ions, with three of its normal modes of motion coupled by a trilinear Hamiltonian such that heat transfer between two modes refrigerates the third. We investigate the dynamics and steady-state properties of the refrigerator and compare its cooling capability when only thermal states are involved to the case when squeezing is employed as a quantum resource. We also study the performance of such a refrigerator in the single shot regime, and demonstrate cooling below both the steady-state energy and the benchmark predicted by the classical thermodynamics treatment.Comment: 11 pages, 7 figures, 2 table

Combination of InSAR with a Depression Angle Model for 3D Deformation Monitoring in Mining Areas

The current three-dimensional (3D) deformation monitoring methods, based on the single line-of-sight (LOS) interferometric synthetic aperture radar (InSAR) technology, are constructed by combining the deformation characteristics of mining subsidence basins, which are incompletely suitable in the edge area of the subsidence basin and some large deformation gradient mines with surface uplift in the LOS direction.The 3D deformation monitoring method of InSAR combined with the surface displacement vector depression angle model (InSAR+ depression angle model) is proposed to obtain more detailed and accurate deformation information of the entire basin. This method first establishes a surface displacement vector depression angle model based on the probability integral method (PIM). The magnitude of the surface displacement vector—owing to the spatial relationship between the LOS direction and the surface displacement vector—is obtained because the horizontal movement direction field and the displacement vector depression angle field of the mining area determine the 3D directions of the surface displacement vector. Then, the PIM model is used to obtain the settlement information of the central area with a large deformation gradient. A complete subsidence basin of the mining area is received by combining the proposed method and the PIM. A total of 35 Sentinel-1A data from 31 March 2018 to 13 May 2019 and the leveling data were used to apply and analyze the accuracy of this method. The experimental results show that this method can obtain more accurate information on surface subsidence around the mining area. Moreover, the overall settlement is more consistent with the actual situation, and the monitoring ability is significantly improved compared with the InSAR and PIM