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It is shown that if one can perform a restricted set of fast manipulations on a quantum system, one can implement a large class of dynamical evolutions by effectively removing or introducing selected Hamiltonians. The procedure can be used…

Quantum Physics · Physics 2009-01-23 Lorenza Viola , Seth Lloyd , Emanuel Knill

Experiments in coherent nuclear and electron magnetic resonance,and quantum computing in general correspond to control of quantum mechanical systems, guiding them from initial to final target states by unitary transformations. The control…

Quantum Physics · Physics 2015-06-17 Haidong Yuan , Daxiu Wei , Yajuan Zhang , Steffen Glaser , Navin Khaneja

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 investigate the control resources needed to effect arbitrary quantum dynamics. We show that the ability to perform measurements on a quantum system, combined with the ability to feed back the measurement results via coherent control,…

Quantum Physics · Physics 2007-05-23 Seth Lloyd , Lorenza Viola

An exact and analytic control protocol of two types of finite dimensional quantum systems is proposed. The system can be drive to an arbitrary target state using cosine classical fields in finite cycles. The control parameters which are…

Quantum Physics · Physics 2015-06-12 Jianju Tang , H. C. Fu

In this paper is presented an abstract theory of quantum processors and controllers, special kind of quantum computational network defined on a composite quantum system with two parts: the controlling and controlled subsystems. Such…

Quantum Physics · Physics 2010-05-12 Alexander Yu. Vlasov

Considering the problem of the control of a two-state quantum system by an external field, we establish a general and versatile method that allows the derivation of smooth pulses, suitable for ultrafast applications, that feature the…

Quantum Physics · Physics 2015-06-15 D. Daems , A. Ruschhaupt , D. Sugny , S. Guerin

The two main notions of control in quantum programming languages are often referred to as "quantum" control and "classical" control. With the latter, the control flow is based on classical information, potentially resulting from a quantum…

Logic in Computer Science · Computer Science 2025-12-01 Kinnari Dave , Louis Lemonnier , Romain Péchoux , Vladimir Zamdzhiev

We describe a fast quantum computer based on optically controlled electron spins in charged quantum dots that are coupled to microcavities. This scheme uses broad-band optical pulses to rotate electron spins and provide the clock signal to…

Quantum Physics · Physics 2009-11-13 Susan M. Clark , Kai-Mei C. Fu , Thaddeus D. Ladd , Yoshihisa Yamamoto

We give an overview of different paradigms for control of quantum systems and their applications, illustrated with specific examples. We further discuss the implications of fault-tolerance requirements for quantum process engineering using…

Quantum Physics · Physics 2016-11-17 Sonia Schirmer , Gajendran Kandasamy , Simon Devitt

Conventional approaches for controlling open quantum systems use coherent control which affects the system's evolution through the Hamiltonian part of the dynamics. Such control, although being extremely efficient for a large variety of…

Quantum Physics · Physics 2009-05-04 Alexander Pechen , Herschel Rabitz

The most basic scenario of quantum control involves the organized manipulation of pure dynamical states of the system by means of unitary transformations. Recently, Vilela Mendes and Mank'o have shown that the conditions for controllability…

Quantum Physics · Physics 2009-11-10 A. Mandilara , J. W. Clark

Simple constructions and protocols are demonstrated to allow the implementation of universal quantum computation on an arbitrarily large quantum system by controlling a fixed number of spins, vastly reducing the engineering requirements in…

Quantum Physics · Physics 2009-04-23 Alastair Kay

Arrays of weakly-coupled quantum systems can be made to compute by subjecting them to a sequence of electromagnetic pulses of well-defined frequency and length. Such pulsed arrays are true quantum computers: bits can be placed in…

Quantum Physics · Physics 2007-05-23 Seth Lloyd

Mathematical theory of the quantum systems control is based on some ideas of the optimal control theory. These ideas are developed here as applied to these systems. The results obtained meet the deficiencies in the basis and algorithms of…

Quantum Physics · Physics 2008-05-22 V. F. Krotov

Numerous lines of experimental, numerical and analytical evidence indicate that it is surprisingly easy to locate optimal controls steering quantum dynamical systems to desired objectives. This has enabled the control of complex quantum…

Quantum Physics · Physics 2015-05-13 Raj Chakrabarti , Herschel Rabitz

We present a scheme for controlling the state of a quantum system by modifying the boundary conditions. This constitutes an infinite-dimensional control problem. We provide conditions for the existence of solutions of the dynamics and prove…

Mathematical Physics · Physics 2024-01-10 A. Balmaseda , J. M. Pérez-Pardo

A quantum system subject to external fields is said to be controllable if these fields can be adjusted to guide the state vector to a desired destination in the state space of the system. Fundamental results on controllability are reviewed…

Nuclear Theory · Physics 2008-11-26 John W. Clark , Dennis G. Lucarelli , Tzyh-Jong Tarn

I revisit the ideas underlying dynamical decoupling methods within the framework of quantum information processing, and examine their potential for direct implementations in terms of encoded rather than physical degrees of freedom. The…

Quantum Physics · Physics 2009-11-07 Lorenza Viola

The control of quantum dynamics via specially tailored laser pulses is a long-standing goal in physics and chemistry. Partly, this dream has come true, as sophisticated pulse shaping experiments allow to coherently control product ratios of…

Quantum Physics · Physics 2007-07-16 J. Werschnik , E. K. U. Gross