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The quantum speed limit sets the minimum time required to transfer a quantum system completely into a given target state. At shorter times the higher operation speed has to be paid with a loss of fidelity. Here we quantify the trade-off…

Quantum Physics · Physics 2015-12-08 Miroslav Gajdacz , Kunal K. Das , Jan Arlt , Jacob F. Sherson , Tomáš Opatrný

We present a theoretical study of the optimal control of a qubit interacting with a structured environment. We consider a model system in which the bath is a bosonic reservoir at zero temperature and the qubit frequency is the only control…

Quantum Physics · Physics 2022-10-04 Quentin Ansel , Jonas Fischer , Dominique Sugny , Bruno Bellomo

A robust control over quantum dynamics is of paramount importance for quantum technologies. Many of the existing control techniques are based on smooth Hamiltonian modulations involving repeated calculations of basic unitaries resulting in…

Quantum Physics · Physics 2016-05-04 Gaurav Bhole , Anjusha V. S. , T. S. Mahesh

We study the efficiency of modulated laser pulses to produce efficient and fast charge localization transitions in a two-electron double quantum dot. We use a configuration interaction method to calculate the electronic structure of a…

Mesoscale and Nanoscale Physics · Physics 2016-03-14 Diego S. Acosta Coden , Rodolfo H. Romero , Alejandro Ferrón , Sergio S. Gomez

Optical techniques have been employed to coherently control the quantum transport through nanojunctions. Conventional works on optical control of quantum transport usually applied a tailored electrical pulses to perform specific tasks. In…

Mesoscale and Nanoscale Physics · Physics 2015-10-13 Yu Zhang

The paper is concerned with the coherent quantum Linear Quadratic Gaussian (CQLQG) control problem for time-varying quantum plants governed by linear quantum stochastic differential equations over a bounded time interval. A controller is…

Quantum Physics · Physics 2012-05-21 Igor G. Vladimirov , Ian R. Petersen

It is control that turns scientific knowledge into useful technology: in physics and engineering it provides a systematic way for driving a system from a given initial state into a desired target state with minimized expenditure of energy…

In this letter, we apply optimal control theory to design minimum-energy $\pi/2$ and $\pi$ pulses for the Bloch system in the presence of relaxation with constrained control amplitude. We consider a commonly encountered case in which the…

Optimization and Control · Mathematics 2014-01-17 Dionisis Stefanatos , Jr-Shin Li

Increasing fidelity is the ultimate challenge of quantum information technology. In addition to decoherence and dissipation, fidelity is affected by internal imperfections such as impurities in the system. Here we show that the quality of…

Quantum Physics · Physics 2013-01-28 E. Rasanen , E. J. Heller

This work considers two-qubit open quantum systems driven by coherent and incoherent controls. Incoherent control induces time-dependent decoherence rates via time-dependent spectral density of the environment which is used as a resource…

Quantum Physics · Physics 2023-09-15 Oleg Morzhin , Alexander Pechen

We investigate the effects of dissipation on the quantum dynamics of many-body systems at quantum transitions, especially considering those of the first order. This issue is studied within the paradigmatic one-dimensional quantum Ising…

Statistical Mechanics · Physics 2020-12-08 Giovanni Di Meglio , Davide Rossini , Ettore Vicari

Dipolar Bose-Einstein condensates have recently attracted much attention in the world of quantum many body experiments. While the theoretical principles behind these experiments are typically supported by numerical simulations, the…

Quantum Physics · Physics 2019-06-25 Jan-Frederik Mennemann , Tim Langen , Lukas Exl , Norbert J. Mauser

Optimal control can be used to significantly improve multi-qubit gates in quantum information processing hardware architectures based on superconducting circuit quantum electrodynamics. We apply this approach not only to dispersive gates of…

Quantum Physics · Physics 2015-05-14 R. Fisher , F. Helmer , S. J. Glaser , F. Marquardt , T. Schulte-Herbrueggen

Coherent carrier control in quantum nanostructures is studied within the framework of Optimal Control. We develop a general solution scheme for the optimization of an external control (e.g., lasers pulses), which allows to channel the…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 Alfio Borzi , Georg Stadler , Ulrich Hohenester

Precisely characterizing and controlling realistic open quantum systems is one of the most challenging and exciting frontiers in quantum sciences and technologies. In this Letter, we present methods of approximately computing reachable sets…

Quantum Physics · Physics 2016-07-13 Jun Li , Dawei Lu , Zhihuang Luo , Raymond Laflamme , Xinhua Peng , Jiangfeng Du

We study the transport property of diffusion in a finite translationally invariant quantum subsystem described by a tight-binding Hamiltonian with a single energy band and interacting with its environment by a coupling in terms of…

Statistical Mechanics · Physics 2010-03-01 Massimiliano Esposito , Pierre Gaspard

Optimal control theory is a versatile tool that presents a route to significantly improving figures of merit for quantum information tasks. We combine it here with the geometric theory for local equivalence classes of two-qubit operations…

Quantum Physics · Physics 2015-03-19 M. M. Müller , D. M. Reich , M. Murphy , H. Yuan , J. Vala , K. B. Whaley , T. Calarco , C. P. Koch

We derive and investigate a general non-Markovian equation for the time-dependence of a Hamiltonian that maximizes the fidelity of a desired quantum gate on any finite-dimensional quantum system in the presence of arbitrary bath and noise…

Quantum Physics · Physics 2016-04-12 Jens Clausen , Guy Bensky , Gershon Kurizki

We present a general theoretical framework for finding the time-optimal unitary evolution of the quantum systems when the Hamiltonian is subject to arbitrary constraints. Quantum brachistochrone (QB) is such a framework based on the…

Quantum Physics · Physics 2020-07-21 Hiroaki Wakamura , Tatsuhiko Koike

Optimal control theory is a powerful tool for improving figures of merit in quantum information tasks. Finding the solution to any optimal control problem via numerical optimization depends crucially on the choice of the optimization…