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Related papers: Feedback Control Using Only Quantum Back-Action

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A theory of feedback controlled heat transport in quantum systems is presented. It is based on modelling heat engines as driven multipartite systems subject to projective quantum measurements and measurement-conditioned unitary evolutions.…

Mesoscale and Nanoscale Physics · Physics 2017-05-29 Michele Campisi , Jukka Pekola , Rosario Fazio

We propose a quantum feedback scheme for producing deterministically reproducible spin squeezing. The results of a continuous nondemolition atom number measurement are fed back to control the quantum state of the sample. For large samples…

Quantum Physics · Physics 2009-11-07 L. K. Thomsen , S. Mancini , H. M. Wiseman

Quantum control refers to our ability to manipulate quantum systems. This tutorial-style chapter focuses on the use of classical electromagnetic fields to steer the system dynamics. In this approach, the quantum nature of the control stems…

Quantum Physics · Physics 2025-12-05 Christiane P. Koch

Feedback control of qubits is a highly demanded technique for advanced quantum information protocols such as quantum error correction. Here we demonstrate active reset of a silicon spin qubit using feedback control. The active reset is…

Mesoscale and Nanoscale Physics · Physics 2023-06-02 Takashi Kobayashi , Takashi Nakajima , Kenta Takeda , Akito Noiri , Jun Yoneda , Seigo Tarucha

Time-continuous quantum measurement allows for the tracking of a quantum system in real time via sequences of short, and individually weak, measurement intervals. Such measurements are necessarily invasive, imparting backaction to the…

Quantum Physics · Physics 2026-04-02 Tathagata Karmakar , Philippe Lewalle , Yipei Zhang , K. Birgitta Whaley

In recent decades the field of quantum computation has seen remarkable development. While much progress has been made toward the realization of a fully digital, scalable, and fault tolerant quantum computer, there are still many essential…

Quantum Physics · Physics 2025-07-31 Ian Pannemarsh

Feedback-based quantum optimization is a quantum approach to combinatorial optimization. In this paper, we introduce the classical counterpart of feedback-based quantum optimization by using the quantum-classical correspondence of spin…

Quantum Physics · Physics 2026-05-14 Tomohiro Hattori , Takuya Hatomura

Many proposals have been put forth for controlling quantum phenomena, including open-loop, adaptive feedback, and real-time feedback control. Each of these approaches has been viewed as operationally, and even physically, distinct from the…

Quantum Physics · Physics 2010-09-14 Alexander Pechen , Constantin Brif , Rebing Wu , Raj Chakrabarti , Herschel Rabitz

Quantum computing employs controllable interactions to perform sequences of logical gates and entire algorithms on quantum registers. This paradigm has been widely explored, e.g., for simulating dynamics of manybody systems by decomposing…

Quantum Physics · Physics 2025-05-21 S. Alipour , A. T. Rezakhani , Alireza Tavanfar , K. Mölmer , T. Ala-Nissila

Recently, feedback-based quantum algorithms have been introduced to calculate the ground states of Hamiltonians, inspired by quantum Lyapunov control theory. This paper aims to generalize these algorithms to the problem of calculating an…

Quantum Physics · Physics 2026-01-21 Salahuddin Abdul Rahman , Özkan Karabacak , Rafal Wisniewski

It is hoped that quantum computers will offer advantages over classical computers for combinatorial optimization. Here, we introduce a feedback-based strategy for quantum optimization, where the results of qubit measurements are used to…

Quantum Physics · Physics 2023-01-05 Alicia B. Magann , Kenneth M. Rudinger , Matthew D. Grace , Mohan Sarovar

We describe the formalism for optimally estimating and controlling both the state of a spin ensemble and a scalar magnetic field with information obtained from a continuous quantum limited measurement of the spin precession due to the…

Quantum Physics · Physics 2007-05-23 John K. Stockton , JM Geremia , Andrew C. Doherty , H. Mabuchi

Feedback control of quantum mechanical systems is rapidly attracting attention not only due to fundamental questions about quantum measurements but also because of its novel applications in many fields in physics. Quantum control has been…

Mesoscale and Nanoscale Physics · Physics 2017-11-15 T. Wagner , P. Strasberg , J. C. Bayer , E. P. Rugeramigabo , T. Brandes , R. J. Haug

Feedback control (based on the quantum continuous measurement) of quantum systems inevitably suffers from estimation delays. In this paper we give a delay-dependent stability criterion for a wide class of nonlinear stochastic systems…

Quantum Physics · Physics 2011-12-05 Kenji Kashima , Naoki Yamamoto

In recent quantum algorithmic developments, a feedback-based approach has shown promise for preparing quantum many-body system ground states and solving combinatorial optimization problems. This method utilizes quantum Lyapunov control to…

Qubit reset is crucial in quantum technology and is typically achieved by coupling the qubit to a dissipative environment. However, the achievable speed and fidelity are limited by qubit-environment entanglement. We use exact tensor-network…

Quantum Physics · Physics 2026-03-11 Carlos Ortega-Taberner , Eoin O'Neill , Paul Eastham

Quantum mechanics dictates that a continuous measurement of the position of an object imposes a random back action perturbation on its momentum. This randomness translates with time into position uncertainty, thus leading to the well known…

The protection of quantum states is challenging for non-orthogonal states especially in the presence of noises. The recent research breakthrough shows that this difficulty can be overcome by feedback control with weak measurements. However,…

Quantum Physics · Physics 2015-06-16 Y. Yang , X. Y. Zhang , J. Ma , X. X. Yi

We study adaptive control of classical ergodic Hamiltonian systems, where the controlling parameter varies slowly in time and is influenced by system's state (feedback). An effective adiabatic description is obtained for slow variables of…

Statistical Mechanics · Physics 2009-11-13 A. E. Allahverdyan , D. B. Saakian

We discuss an efficient numerical scheme for the recursive filtering of diffusive quantum stochastic master equations. We show that the resultant quantum trajectory is robust and may be used for feedback based on inefficient measurements.…

Quantum Physics · Physics 2015-04-20 Pierre Rouchon , Jason F. Ralph