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There is a strong interest in optimal manipulating of quantum systems by external controls. Traps are controls which are optimal only locally but not globally. If they exist, they can be serious obstacles to the search of globally optimal…

Quantum Physics · Physics 2015-09-03 Alexander Pechen , Nikolay Il'in

Starting with the basic control system model often employed in NMR pulse design, we derive more realistic control system models taking into account effects such as off-resonant excitation for systems with fixed inter-qubit coupling…

Quantum Physics · Physics 2009-10-01 Sonia Schirmer

Various constraints concerning control fields can be imposed in the realistic implementations of quantum control systems. One of the most important is the restriction on the frequency spectrum of acceptable control parameters. It is…

Quantum Physics · Physics 2014-02-28 Łukasz Pawela , Zbigniew Puchała

Quantum control can be employed in quantum metrology to improve the precision limit for the estimation of unknown parameters. The optimal control, however, typically depends on the actual values of the parameters and thus needs to be…

Quantum Physics · Physics 2021-04-30 Han Xu , Lingna Wang , Haidong Yuan , Xin Wang

An incoherent control scheme for state control of locally controllable quantum systems is proposed. This scheme includes three steps: (1) amplitude amplification of the initial state by a suitable unitary transformation, (2) projective…

Quantum Physics · Physics 2008-10-22 Daoyi Dong , Chenbin Zhang , Herschel Rabitz , Alexander Pechen , Tzyh-Jong Tarn

Robust and high-precision quantum control is extremely important but challenging for the functionization of scalable quantum computation. In this paper, we show that this hard problem can be translated to a supervised machine learning task…

Quantum Physics · Physics 2019-04-24 Re-Bing Wu , Haijin Ding , Daoyi Dong , Xiaoting Wang

The control of quantum system dynamics is generally performed by seeking a suitable applied field. The physical objective as a functional of the field forms the quantum control landscape, whose topology, under certain conditions, has been…

Quantum Physics · Physics 2014-11-11 Arun Nanduri , Ofer M. Shir , Ashley Donovan , Tak-San Ho , Herschel Rabitz

In this work, we adopt the Gradient Projection Method (GPM) to problems of quantum control. For general $N$-level closed and open quantum systems, we derive the corresponding adjoint systems and gradients of the objective functionals, and…

Quantum Physics · Physics 2025-09-03 Oleg Morzhin , Alexander Pechen

A major obstacle in the way of practical quantum computing is achieving scalable and robust high-fidelity entangling gates. To this end, quantum control has become an essential tool, as it can make the entangling interaction resilient to…

Quantum Physics · Physics 2022-10-05 Christophe H. Valahu , Iason Apostolatos , Sebastian Weidt , Winfried K. Hensinger

Quantized integrable systems can be made to perform universal quantum computation by the application of a global time-varying control. The action-angle variables of the integrable system function as qubits or qudits, which can be coupled…

Quantum Physics · Physics 2014-08-05 Seth Lloyd , Simone Montangero

Quantum control aims to manipulate quantum systems toward specific quantum states or desired operations. Designing highly accurate and effective control steps is vitally important to various quantum applications, including energy…

Quantum Physics · Physics 2023-01-11 Xinyu Fei , Lucas T. Brady , Jeffrey Larson , Sven Leyffer , Siqian Shen

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

We discuss the use of incoherent light as a resource to control the atomic dynamics and review the proposed in Phys. Rev. A 84, 042106 (2011) method for a controlled transfer between any pure and mixed states of quantum systems using a…

Quantum Physics · Physics 2012-12-12 Alexander Pechen

Quantum control is concerned with active manipulation of physical and chemical processes on the atomic and molecular scale. This work presents a perspective of progress in the field of control over quantum phenomena, tracing the evolution…

Quantum Physics · Physics 2010-07-20 Constantin Brif , Raj Chakrabarti , Herschel Rabitz

We prove that the environment induced entanglement between two non interacting, two-dimensional quantum systems S and P can be used to control the dynamics of S by means of the initial state of P. Using a simple, exactly solvable model, we…

Quantum Physics · Physics 2009-11-11 Raffaele Romano , Domenico D'Alessandro

Accurate models for open quantum systems -- quantum states that have non-trivial interactions with their environment -- may aid in the advancement of a diverse array of fields, including quantum computation, informatics, and the prediction…

We demonstrate the use of optimal control to design two entropy-manipulating quantum gates which are more complex than the corresponding, commonly used, gates, such as CNOT and Toffoli (CCNOT): A 2-qubit gate called PE (polarization…

Quantum Physics · Physics 2014-11-19 Yosi Atia , Yuval Elias , Tal Mor , Yossi Weinstein

We present an iterative optimal control method of quantum systems, aimed at an implementation of a desired operation with optimal fidelity. The update step of the method is based on the linear response of the fidelity to the control…

Quantum Physics · Physics 2025-02-06 Nicolas Heimann , Lukas Broers , Ludwig Mathey

Quantum computing is a fascinating interdisciplinary research field that promises to revolutionize computing by efficiently solving previously intractable problems. Recent years have seen tremendous progress on both the experimental…

Systems and Control · Electrical Eng. & Systems 2024-12-04 Julian Berberich , Daniel Fink

We show that the second order traps in the control landscape for a three-level $\Lambda$-system found in our previous work {\it Phys. Rev. Lett.} {\bf 106}, 120402 (2011) are not local maxima: there exist directions in the space of controls…

Quantum Physics · Physics 2015-08-19 Alexander Pechen , David J. Tannor
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