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The current quantum reinforcement learning control models often assume that the quantum states are known a priori for control optimization. However, full observation of quantum state is experimentally infeasible due to the exponential…

Quantum Physics · Physics 2022-06-30 Chen Jiang , Yu Pan , Zheng-Guang Wu , Qing Gao , Daoyi Dong

Quantum systems can be exquisite sensors thanks to their sensitivity to external perturbations. This same characteristic also makes them fragile to external noise. Quantum control can tackle the challenge of protecting quantum sensors from…

Quantum Physics · Physics 2018-06-13 F. Poggiali , P. Cappellaro , N. Fabbri

Reconstructing DNA sequences without a reference, known as de novo assembly, is a complex computational task involving the alignment of overlapping fragments. To address this problem, a usual strategy is to map the assembly to a Quadratic…

In this work, we address the problem of maximizing fidelity in a quantum state transformation process controlled in such a way as to keep decoherence within given bounds. We consider a three-level $\Lambda$-type atom subjected to Markovian…

Quantum Physics · Physics 2022-03-30 Nahid Binandeh Dehaghani , Fernando Lobo Pereira

Control of quantum systems is a central element of high-precision experiments and the development of quantum technological applications. Control pulses that are typically temporally or spatially modulated are often designed based on…

Quantum Physics · Physics 2021-01-04 Frederic Sauvage , Florian Mintert

Combinatorial optimization problems are one of the areas where near-term noisy quantum computers may have practical advantage against classical computers. Recently a novel feedback-based quantum optimization algorithm has been proposed by…

Quantum Physics · Physics 2025-01-13 Don Arai , Ken N. Okada , Yuichiro Nakano , Kosuke Mitarai , Keisuke Fujii

Quantum optimal control can play a crucial role to realize a set of universal quantum logic gates with error rates below the threshold required for fault-tolerance. Open-loop quantum optimal control relies on accurate modeling of the…

Quantum Physics · Physics 2018-12-05 Guanru Feng , Franklin H. Cho , Hemant Katiyar , Jun Li , Dawei Lu , Jonathan Baugh , Raymond Laflamme

We give an introduction to feedback control in quantum systems, as well as an overview of the variety of applications which have been explored to date. This introductory review is aimed primarily at control theorists unfamiliar with quantum…

Quantum Physics · Physics 2007-05-23 Kurt Jacobs

Quantum optimal control involves setting up an objective function that evaluates the quality of an operator representing the realized process w.r.t. the target process. Here we propose a stronger objective function which incorporates not…

Quantum Physics · Physics 2020-03-18 Priya Batra , V. R. Krithika , T. S. Mahesh

A reinforcement algorithm solves a classical optimization problem by introducing a feedback to the system which slowly changes the energy landscape and converges the algorithm to an optimal solution in the configuration space. Here, we use…

Disordered Systems and Neural Networks · Physics 2017-11-08 A. Ramezanpour

Quantum control is concerned with the realisation of desired dynamics in quantum systems, serving as a linchpin for advancing quantum technologies and fundamental research. Analytic approaches and standard optimisation algorithms do not…

Quantum Physics · Physics 2025-05-29 Jan Ole Ernst , Aniket Chatterjee , Tim Franzmeyer , Axel Kuhn

Quantum mechanical systems exhibit an inherently probabilistic nature upon measurement. Using a quantum noise model to describe the stochastic evolution of the open quantum system and working in parallel with classical indeterministic…

Quantum Physics · Physics 2007-05-23 S. C. Edwards , V. P. Belavkin

In this paper we formulate a risk-sensitive optimal control problem for continuously monitored open quantum systems modelled by quantum Langevin equations. The optimal controller is expressed in terms of a modified conditional state, which…

Quantum Physics · Physics 2016-09-08 M. R. James

Combinatorial optimization is a promising application for near-term quantum computers, however, identifying performant algorithms suited to noisy quantum hardware remains as an important goal to potentially realizing quantum computational…

Quantum Physics · Physics 2025-04-01 Titus D. Morris , Ananth Kaushik , Martin Roetteler , Phillip C. Lotshaw

Quantum optimal control is a set of methods for designing time-varying electromagnetic fields to perform operations in quantum technologies. This tutorial paper introduces the basic elements of this theory based on the Pontryagin maximum…

Quantum Physics · Physics 2024-06-17 Q. Ansel , E. Dionis , F. Arrouas , B. Peaudecerf , S. Guérin , D. Guéry-Odelin , D. Sugny

Quantum Computing aims to streamline machine learning, making it more effective with fewer trainable parameters. This reduction of parameters can speed up the learning process and reduce the use of computational resources. However, in the…

Quantum Physics · Physics 2024-05-22 Michael Kölle , Timo Witter , Tobias Rohe , Gerhard Stenzel , Philipp Altmann , Thomas Gabor

Optimal control theory is an effective tool to improve parameter estimation of quantum systems. Different methods can be employed for the design of the control protocol. They can be based either on Quantum Fischer Information (QFI)…

Quantum Physics · Physics 2023-06-21 Quentin Ansel , Etienne Dionis , Dominique Sugny

Variational quantum algorithms (VQAs) have established themselves as a central computational paradigm in the Noisy Intermediate-Scale Quantum (NISQ) era. By coupling parameterized quantum circuits (PQCs) with classical optimization, they…

The control of individual quantum systems is now a reality in a variety of physical settings. Feedback control is an important class of control methods because of its ability to reduce the effects of noise. In this review we give an…

Quantum Physics · Physics 2017-08-01 Jing Zhang , Yu-xi Liu , Re-Bing Wu , Kurt Jacobs , Franco Nori

Achieving high-fidelity control of quantum systems is of fundamental importance in physics, chemistry and quantum information sciences. However, the successful implementation of a high-fidelity quantum control scheme also requires…

Quantum Physics · Physics 2018-06-05 Yu Guo , Daoyi Dong , Chuan-Cun Shu