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We solve two long standing problems for stochastic descriptions of open quantum system dynamics. First, we find the classical stochastic processes corresponding to non-Markovian quantum state diffusion and non-Markovian quantum jumps in…

Quantum Physics · Physics 2020-10-14 Kimmo Luoma , Walter T. Strunz , Jyrki Piilo

The non-Markovian nature of quantum systems recently turned to be a key subject for investigations on open quantum system dynamics. Many studies, from its theoretical grounding to its usefulness as a resource for quantum information…

Non-Markovian Quantum State Diffusion (NMQSD) has turned out to be an efficient method to calculate excitonic properties of aggregates composed of organic chromophores, taking into account the coupling of electronic transitions to…

Chemical Physics · Physics 2015-06-22 Gerhard Ritschel , Daniel Suess , Sebastian Möbius , Walter T. Strunz , Alexander Eisfeld

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

The study of open quantum systems is important for fundamental issues of quantum physics as well as for technological applications such as quantum information processing. The interaction of a quantum system with it's environment is usually…

Quantum Physics · Physics 2016-02-02 Jun Sun , Yong-Nan Sun , Chuan-Feng Li , Guang-Can Guo , Kimmo Luoma , Jyrki Piilo

Collectively-encoded qubits, involving ensembles of atomic or solid-state emitters, present many practical advantages for quantum technologies. However, they suffer from uncontrolled inhomogeneous dephasing which couples them to a…

Quantum Physics · Physics 2025-11-10 Antoine Covolo , Valentin Magro , Mathieu Girard , Sébastien Garcia , Alexei Ourjoumtsev

We theoretically investigate the non-equilibrium quantum dynamical theory of a quantum dot system coupled to fermionic reservoirs using the recently developed stochastic fermionic quantum state diffusion (FQSD) equation. The exact or…

Quantum Physics · Physics 2018-12-07 Wufu Shi , Yusui Chen , Lihui Sun , J. Q. You , Ting Yu

In this paper, we first design a type of Bang-Bang (BB) operation group to reduce the phase decoherence in a {\Xi}-type n-level quantum system based on the dynamical decoupling mechanism. Then, we derive two kinds of dynamical decoupling…

Quantum Physics · Physics 2014-04-29 Linping Chan , Shuang Cong

Realistic quantum mechanical systems are always exposed to an external environment. The presence of the environment often gives rise to a Markovian process in which the system loses information to its surroundings. However, many quantum…

We study the dynamics of the two-level atomic systems (qubits) under a double-layer environment that is consisted of a network of single-mode cavities coupled to a common reservoir. A general exact master equation for the dynamics can be…

Quantum Physics · Physics 2019-05-21 Yu-Long Qiao , Jia-Ming Zhang , Yusui Chen , Jun Jing , Shi-Yao Zhu

We address a wide spectrum of quantum control strategies, including various open-loop protocols and advanced adaptive methods. These methodologies apply to few-qubit scenarios and naturally scale to larger N-qubit systems. We benchmark them…

Quantum Physics · Physics 2025-09-22 Atta ur Rahman , M. Y. Abd-Rabbou , Cong-feng Qiao

The present work analyzes state-stabilization techniques for decoupling a subsystem from environmental interactions. The proposed framework uses analytical and numerical tools to find an approximate decoherence-free subspace (DFS) with…

Quantum Physics · Physics 2025-07-11 Miguel Casanova , Francesco Ticozzi

In this paper, the non-Markovian quantum dynamics of a coupled $N$-cavity model is studied based on the quantum state diffusion (QSD) approach. The time-local Di\'{o}si-Gisin-Strunz equation and the corresponding exact master equation are…

Quantum Physics · Physics 2014-04-08 Xinyu Zhao , Jun Jing , J. Q. You , Ting Yu

Stochastic unravelings represent a useful tool to describe the dynamics of open quantum systems and standard methods, such as quantum state diffusion (QSD), call for the complete positivity of the open-system dynamics. Here, we present a…

Quantum Physics · Physics 2017-07-04 Matteo Caiaffa , Andrea Smirne , Angelo Bassi

We present a theoretical proposal for preparing and manipulating a state of a single continuous-variable degree of freedom confined to a nonharmonic potential. By utilizing optimally controlled modulation of the potential's position and…

Quantum Physics · Physics 2025-08-13 Piotr T. Grochowski , Hannes Pichler , Cindy A. Regal , Oriol Romero-Isart

It is shown that if one can perform a restricted set of fast manipulations on a quantum system, one can implement a large class of dynamical evolutions by effectively removing or introducing selected Hamiltonians. The procedure can be used…

Quantum Physics · Physics 2009-01-23 Lorenza Viola , Seth Lloyd , Emanuel Knill

We present a channel-constrained Markovian quantum diffusion (CCMQD) model that prepares quantum states by rigorously framing the generative process within the dynamics of open quantum systems. Our model interprets the forward diffusion…

Quantum Physics · Physics 2025-11-18 Qin-Sheng Zhu , Geng Chen , Lian-Hui Yu , Xiaodong Xing , Xiao-Yu Li

We implement dynamical decoupling techniques to mitigate noise and enhance the lifetime of an entangled state that is formed in a superconducting flux qubit coupled to a microscopic two-level system. By rapidly changing the qubit's…

We investigate the quantum correlation dynamics of three independent qubits each locally interacting with a zero temperature non-Markovian reservoir by using the Geometric measure of quantum discord (GQD). The dependence of quantum…

Quantum Physics · Physics 2024-05-01 M. A. Shukri , Fares S. S. Alzahri , Ali Saif M. Hassan

The state-dependent diffusion, which concerns the Brownian motion of a particle in inhomogeneous media has been described phenomenologically in a number of ways. Based on a system-reservoir nonlinear coupling model we present a microscopic…

Statistical Mechanics · Physics 2007-05-23 Debashis Barik , Deb Shankar Ray