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Related papers: Quantum Feedback Networks: Hamiltonian Formulation

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We consider the problem of frequency estimation for a single bosonic field evolving under a squeezing Hamiltonian and continuously monitored via homodyne detection. In particular, we exploit reinforcement learning techniques to devise…

Quantum Physics · Physics 2022-04-19 Alessio Fallani , Matteo A. C. Rossi , Dario Tamascelli , Marco G. Genoni

Response functions are a fundamental aspect of physics; they represent the link between experimental observations and the underlying quantum many-body state. However, this link is often under-appreciated, as the Lehmann formalism for…

Quantum Physics · Physics 2023-02-22 Efekan Kökcü , Heba A. Labib , J. K. Freericks , Alexander F. Kemper

The goal in quantum state transfer is to avoid the need to physically transport carriers of quantum information. This is achieved by using a suitably engineered Hamiltonian that induces the transfer of the state of one subsystem to another.…

Using a quantum circuit model we derive the maximal ability to distinguish which of several candidate Hamiltonians describe an open quantum system. This theory, in particular, provides the maximum information retrievable from continuous…

Quantum Physics · Physics 2015-06-22 Klaus Molmer

We introduce a general framework, based on collision models and discrete CP-maps, to describe on an equal footing coherent and measurement-based feedback control of quantum mechanical systems. We apply our framework to prominent tasks in…

Quantum Physics · Physics 2023-10-23 Alfred Harwood , Matteo Brunelli , Alessio Serafini

The spin network simulator model represents a bridge between (generalized) circuit schemes for standard quantum computation and approaches based on notions from Topological Quantum Field Theories (TQFT). More precisely, when working with…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Silvano Garnerone , Annalisa Marzuoli , Mario Rasetti

Quantum tracking control encodes the desired dynamics into a tailored driving field; here, we let the system find its own way there. We propose a real-time feedback control framework in which a proportional controller continuously corrects…

Quantum Physics · Physics 2026-03-06 Valeriia Bilokon , Elvira Bilokon , Denys I. Bondar

The model of light-matter interaction in quantum electrodynamics typically relies on the Markovian approximation, which assumes that the system's future evolution depends solely on its current state, effectively treating it as a…

As quantum machine-learning architectures mature, a central challenge is no longer their construction, but identifying the regimes in which they offer practical advantages over classical approaches. In this work, we introduce a framework…

Machine Learning · Computer Science 2026-01-21 Brandon B. Le , D. Keller

Communication over a quantum multiple access channel (MAC) is considered with classical feedback. Since the no-cloning prohibits universal copying of arbitrary quantum states, classical feedback is generated through measurement. An…

Quantum Physics · Physics 2026-02-20 Elina Levi , Uzi Pereg

We present a theory of finite-frequency noise in non-equilibrium conductors. It is shown that Non-Markovian correlations are essential to describe the physics of quantum noise. In particular, we show the importance of a correct treatment of…

Mesoscale and Nanoscale Physics · Physics 2011-04-01 D. Marcos , C. Emary , T. Brandes , R. Aguado

Feedback uses past detection outcomes to dynamically modify a quantum system and is central to quantum control. These outcomes can be stored in a memory, defined as a stochastic function of past measurements. In this work, we investigate…

Quantum Physics · Physics 2025-12-10 Alberto J. B. Rosal , Patrick P. Potts , Gabriel T. Landi

The purpose of this paper is to present a comprehensive study of a coherent feedback network where the main component consists of two distant double quantum dot (DQD) qubits which are directly coupled to a cavity. This main component has…

Quantum Physics · Physics 2020-04-09 Zhiyuan Dong , Wei Cui , Guofeng Zhang

In the context of a charge qubit under continuous monitoring by a single electron transistor, we propose an unraveling of the generalized quantum Markovian master equation into an ensemble of individual quantum trajectories for stochastic…

Mesoscale and Nanoscale Physics · Physics 2015-02-26 JunYan Luo , Jinshuang Jin , Shi-Kuan Wang , Jing Hu , Yixiao Huang , Xiao-Ling He

We present a formulation of feedback in quantum systems in which the best estimates of the dynamical variables are obtained continuously from the measurement record, and fed back to control the system. We apply this method to the problem of…

Quantum Physics · Physics 2009-10-31 A. C. Doherty , K. Jacobs

We consider hamiltonian models representing an arbitrary number of spin $1/2$ fermion quantum fields interacting through arbitrary processes of creation or annihilation of particles. The fields may be massive or massless. The interaction…

Mathematical Physics · Physics 2020-01-08 Benjamin Alvarez , Jérémy Faupin , Jean-Claude Guillot

The feedback-based algorithm for quantum optimization (FALQON) has recently been proposed to solve quadratic unconstrained binary optimization problems. This paper efficiently generalizes FALQON to tackle quadratic constrained binary…

Quantum Physics · Physics 2025-04-15 Salahuddin Abdul Rahman , Özkan Karabacak , Rafal Wisniewski

Quantum algorithms have the potential to revolutionize our understanding of open quantum systems in chemistry. In this work, we demonstrate that a repeated interaction model, which could serve as the foundation for a digital quantum…

Quantum Physics · Physics 2025-05-05 Lea K. Northcote , Matthew S. Teynor , Gemma C. Solomon

It has earlier been argued that there should exist a formulation of quantum mechanics which does not refer to a background spacetime. In this paper we propose that, for a relativistic particle, such a formulation is provided by a…

General Relativity and Quantum Cosmology · Physics 2007-05-23 T. P. Singh

We address the nonadiabatic quantum dynamics of macrosystems with several coupled electronic states, taking into account the possibility of multi-state conical intersections. The general situation of an arbitrary number of states and…

Chemical Physics · Physics 2009-11-13 Etienne Gindensperger , Lorenz S. Cederbaum