Minimal coupling method and the dissipative scalar field theory

d+1维中与动力学Neumann表面耦合的实标量场的量子耗散效应

Quantum dissipative effects for a real scalar field coupled to a dynamical Neumann surface in d+1 dimensions

该研究比较了d+1维中满足Neumann和Dirichlet边界条件的实标量场的量子耗散效应，发现d=1时两者在特定阶数上相等，并给出了d>1时差异的一般表达式。

耗散泵浦与兰姆移位进动产生的标量自旋手性

Scalar Spin Chirality from Dissipative Pumping and Lamb Shift Precession

该研究针对三角三量子点中循环电流随偏置反转的不明起源，提出耗散隧穿制备轨道赝自旋、虚拟电荷涨落产生兰姆场的机制，通过储库诱导的轨道 Hanle 效应将轨道极化转化为标量自旋手性，经层级计算验证了低偏置反转与手性进动的特性。

Relativistic and non-relativistic quantum Brownian motion in an anisotropic dissipative medium

Using a minimal-coupling-scheme we investigate the quantum Brownian motion of a particle in an anisotropic-dissipative-medium under the influence of an arbitrary potential in both relativistic and non-relativistic regimes. A general quantum Langevin equation is derived and explicit expressions for quantum-noise and dynamical variables of the system are obtained. The equations of motion for the canonical variables are solved explicitly and an expression for the radiation-reaction of a charged particle in the presence of a dissipative-medium is obtained. Some examples are given to elucidate the …

Quantum dissipative systems from theory of continuous measurements

We apply the restricted-path-integral (RPI) theory of non-minimally disturbing continuous measurements for correct description of frictional Brownian motion. The resulting master equation is automatically of the Lindblad form, so that the difficulties typical of other approaches do not exist. In the special case of harmonic oscillator the known familiar master equation describing its frictionally driven Brownian motion is obtained. A thermal reservoir as a measuring environment is considered.

Dissipative engineering of Gaussian entangled states in harmonic lattices with a single-site squeezed reservoir

We study the dissipative preparation of many-body entangled Gaussian states in bosonic lattice models which could be relevant for quantum technology applications. We assume minimal resources, represented by systems described by particle-conserving quadratic Hamiltonians, with a single localized squeezed reservoir. We show that in this way it is possible to prepare, in the steady state, the wide class of pure states which can be generated by applying a generic passive Gaussian transformation on a set of equally squeezed modes. This includes non-trivial multipartite entangled states such as clus…

利用自适应开放量子动力学加速耗散态制备

Accelerating Dissipative State Preparation with Adaptive Open Quantum Dynamics

本文提出一种极简自适应动力学方法，规避耗散态制备中的时间-纠缠权衡，在有限时间尺度内实现最大纠缠态及多体纠缠量子比特态的加速耗散稳定化。

Minimal informationally complete measurements for probability representation of quantum dynamics

In the present work, we suggest an approach for describing dynamics of finite-dimensional quantum systems in terms of pseudostochastic maps acting on probability distributions, which are obtained via minimal informationally complete quantum measurements. The suggested method for probability representation of quantum dynamics preserves the tensor product structure, which makes it favourable for the analysis of multi-qubit systems. A key advantage of the suggested approach is that minimal informationally complete positive operator-valued measures (MIC-POVMs) are easier to construct in comparison…

Quantum dissipative effects in moving mirrors: a functional approach

We use a functional approach to study various aspects of the quantum effective dynamics of moving, planar, dispersive mirrors, coupled to scalar or Dirac fields, in different numbers of dimensions. We first compute the Euclidean effective action, and use it to derive the imaginary part of the `in-out' effective action. We also obtain, for the case of the real scalar field in 1+1 dimensions, the Schwinger-Keldysh effective action and a semiclassical Langevin equation that describes the motion of the mirror including noise and dissipative effects due to its coupling to the quantum fields.

Minimally dissipative information erasure in a quantum dot via thermodynamic length

In this work we explore the use of thermodynamic length to improve the performance of experimental protocols. In particular, we implement Landauer erasure on a driven electron level in a semiconductor quantum dot, and compare the standard protocol in which the energy is increased linearly in time with the one coming from geometric optimisation. The latter is obtained by choosing a suitable metric structure, whose geodesics correspond to optimal finite-time thermodynamic protocols in the slow driving regime. We show experimentally that geodesic drivings minimise dissipation for slow protocols, …

Many-Body Dissipative Flow of a Confined Scalar Bose-Einstein Condensate Driven by a Gaussian Impurity

The many-body dissipative flow induced by a mobile aussian impurity harmonically oscillating within a cigar-shaped Bose-Einstein condensate is investigated. For very {small and large driving frequencies} the superfluid phase is preserved. Dissipation is identified, for intermediate driving frequencies, by the non-zero value of the drag force whose abrupt increase {signals the spontaneous downstream emission of an array of gray solitons. After each emission event, typically each of the solitary waves formed decays and splits into two daughter gray solitary waves that are found to be robust prop…

耗散CSL模型的波函数公式

Wave-functional formulation of dissipative CSL models

研究非相对论玻色子场中耗散CSL模型，在泛函薛定谔表示下建立公式，通过扇区投影获固定粒子数波函数，考虑耗散扩展，单粒子扇区再现能量平衡，多体扇区有额外项，集体对摩擦产生非广延稳态平均动能。

弱场区域中耗散二能级原子的引力效应

Gravitational effects on a dissipative two-level atom in the weak-field regime

利用Feynman-Vernon影响泛函形式，推导了牛顿引力场中二能级原子与标量场相互作用的量子主方程，发现自发辐射率受引力修正，且修正依赖于原子偶极、位置及辐射频率，并识别了引力增强或抑制自发辐射的参数区域。

Quantum limit of laser cooling in dispersively- and dissipatively-coupled optomechanical systems

Mechanical oscillators can be cooled by coupling them to an optical or microwave cavity. Going beyond the standard quantum noise approach we find an analytic expression for the steady-state phonon number in systems where the position of the mechanical oscillator modulates the cavity frequency as well as the cavity line width. We trace the origin for the quantum limit of cooling to fluctuations in the optical force both at and away from the mechanical frequency. Finally, we calculate the minimal phonon number for the different types of coupling. Our study elucidates how to beneficially combine …