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Investigations of quantum and mesoscopic thermodynamics force one to answer two fundamental questions associated with the foundations of statistical mechanics: (i) how does macroscopic irreversibility emerge from microscopic reversibility?…

Quantum Physics · Physics 2019-02-20 Wei-Min Zhang

We develop dynamical non-Markovian description of quantum computing in weak coupling limit, in lowest order approximation. We show that long range memory of quantum reservoir produces strong interrelation between structure of noise and…

Quantum Physics · Physics 2009-11-07 Robert Alicki , Michal Horodecki , Pawel Horodecki , Ryszard Horodecki

This paper addresses the optimal control of quantum coherence in multi-level systems, modeled by the Lindblad master equation, which captures both unitary evolution and environmental dissipation. We develop an energy minimization framework…

Quantum Physics · Physics 2024-11-19 Nahid Binandeh Dehaghani , A. Pedro Aguiar , Rafal Wisniewski

Motivated by recent work showing that a quantum error correcting code can be generated by hybrid dynamics of unitaries and measurements, we study the long time behavior of such systems. We demonstrate that even in the "mixed" phase, a…

Quantum Physics · Physics 2022-08-02 Lukasz Fidkowski , Jeongwan Haah , Matthew B. Hastings

Continuous-time stochastic processes pervade everyday experience, and the simulation of models of these processes is of great utility. Classical models of systems operating in continuous-time must typically track an unbounded amount of…

Quantum Physics · Physics 2018-03-05 Thomas J. Elliott , Mile Gu

The dynamical behavior of open quantum systems plays a key role in many applications of quantum mechanics, examples ranging from fundamental problems, such as the environment-induced decay of quantum coherence and relaxation in many-body…

Quantum Physics · Physics 2016-05-04 Heinz-Peter Breuer , Elsi-Mari Laine , Jyrki Piilo , Bassano Vacchini

Generic open quantum dynamics can be described by two seemingly very distinct approaches: a top down approach by considering an (unknown) environment coupled to the system and affects the observed dynamics of the system; or a bottom up…

Quantum Physics · Physics 2022-03-31 Chu Guo

We provide several quantum algorithms for continuous optimization that do not require gradient estimation. Instead, we encode the optimization problem into the dynamics of a physical system and coherently simulate the time evolution. We…

Quantum Physics · Physics 2026-03-18 Ahmet Burak Catli , Sophia Simon , Nathan Wiebe

Protecting information against decoherence in open quantum systems remains a central challenge for quantum computing. In particular, passive error correction schemes have so far been limited to static memories rather than dynamical qubits.…

Quantum Physics · Physics 2026-02-25 Mert Esencan , A. I. Lvovsky , Berislav Buča

With rapid advancements in machine learning, first-order algorithms have emerged as the backbone of modern optimization techniques, owing to their computational efficiency and low memory requirements. Recently, the connection between…

Quantum Physics · Physics 2025-05-21 Jiaqi Leng , Bin Shi

Variational quantum algorithms (VQAs) have emerged as a promising approach for achieving quantum advantage on current noisy intermediate-scale quantum devices. However, their large-scale applications are significantly hindered by…

Quantum Physics · Physics 2026-03-03 Shikun Zhang , Zheng Qin , Yongyou Zhang , Yang Zhou , Rui Li , Chunxiao Du , Zhisong Xiao

Quantum information processing requires overcoming decoherence---the loss of "quantumness" due to the inevitable interaction between the quantum system and its environment. One approach towards a solution is quantum dynamical decoupling---a…

Quantum Physics · Physics 2011-07-26 Xinhua Peng , Dieter Suter , Daniel A. Lidar

The optimal control problem for open quantum systems can be formulated as a time-dependent Lindbladian that is parameterized by a number of time-dependent control variables. Given an observable and an initial state, the goal is to tune the…

Quantum Physics · Physics 2024-05-30 Wenhao He , Tongyang Li , Xiantao Li , Zecheng Li , Chunhao Wang , Ke Wang

Quantum open systems are described in the Markovian limit by master equations in Lindblad form. I argue that common ``quantum trajectory'' techniques corresponding to continuous measurement schemes, which solve the master equation by…

Quantum Physics · Physics 2009-10-30 Todd A. Brun

We describe and demonstrate a method for the computation of quantum dynamics on small, noisy universal quantum computers. This method relies on the idea of `restarting' the dynamics; at least one approximate time step is taken on the…

Quantum Physics · Physics 2019-10-15 Matthew Otten , Cristian L. Cortes , Stephen K. Gray

We present an approach that allows quantifying decoherence processes in an open quantum system subject to external time-dependent control. Interactions with the environment are modeled by a standard bosonic heat bath. We develop two…

Mesoscale and Nanoscale Physics · Physics 2010-10-12 Dmitry Solenov , Vladimir Privman

Unwanted interaction between a quantum system and its fluctuating environment leads to decoherence and is the primary obstacle to establishing a scalable quantum information processing architecture. Strategies such as environmental and…

We propose Quantum Riemannian Hamiltonian Descent (QRHD), a quantum algorithm for continuous optimization on Riemannian manifolds that extends Quantum Hamiltonian Descent (QHD) by incorporating geometric structure of the parameter space via…

Quantum Physics · Physics 2026-03-31 Yoshihiko Abe , Ryo Nagai

Noise in quantum devices is generally considered detrimental to computational accuracy. However, the recent proposal of noise-assisted simulation has demonstrated that noise can be an asset in digital quantum simulations of open systems on…

We present the Reduced Operator Approximation: a simple, physically transparent and computationally efficient method of modelling open quantum systems. It employs the Heisenberg picture of the quantum dynamics, which allows us to focus on…

Quantum Physics · Physics 2015-08-06 Agnieszka Werpachowska