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An iterative learning algorithm is presented for continuous-time linear-quadratic optimal control problems where the system is externally symmetric with unknown dynamics. Both finite-horizon and infinite-horizon problems are considered. It…

Optimization and Control · Mathematics 2025-10-10 Hamed Taghavian , Florian Dorfler , Mikael Johansson

We demonstrate that the current laser technology used for field-free molecular alignment via a cascade of Raman rotational transitions allows for observing long-discussed non-linear quantum phenomena in the dynamics of the periodically…

Quantum Physics · Physics 2015-05-30 Johannes Floß , Ilya Sh. Averbukh

Controlling molecular reactivity by shaped laser pulses is a long-standing goal in chemistry. Here we suggest a direct optimal control approach which combines external pulse optimization with other control parameters arising in the upcoming…

Quantum Physics · Physics 2024-01-03 A. R. Ramos Ramos , E. W. Fischer , P. Saalfrank , O. Kühn

The angular momentum of molecules, or, equivalently, their rotation in three-dimensional space, is ideally suited for quantum control. Molecular angular momentum is naturally quantized, time evolution is governed by a well-known Hamiltonian…

Quantum Physics · Physics 2019-10-23 Christiane P. Koch , Mikhail Lemeshko , Dominique Sugny

The capability to control molecular rotation for field-free orientation, which arranges molecules in specific spatial directions without external fields, is crucial in physics, chemistry, and quantum information science. However,…

Quantum Physics · Physics 2025-12-25 Qian-Qian Hong , Zhe-Jun Zhang , Chuan-Cun Shu , Jun He , Daoyi Dong , Dajun Ding

Combining the features of molecular wires and femtosecond laser pulses gives the unique opportunity to optically switch electron currents in molecular devices with very high speed. Based on a weak-coupling approximation between wire and…

Mesoscale and Nanoscale Physics · Physics 2007-08-22 GuangQi Li , Sven Welack , Michael Schreiber , Ulrich Kleinekathoefer

We propose and computationally study a method for simultaneously orienting the angular momentum of asymmetric top molecules along: 1) a laboratory-fixed direction; 2) the molecular intermediate moment of inertia axis; 3) the laser field…

Quantum Physics · Physics 2022-11-21 Emil J. Zak

Inducing and controlling the ultrafast molecular rotational dynamics using shaped laser fields is essential in numerous applications. Several approaches exist that allow following the coherent molecular motion in real-time, including…

Laser control of molecular rotation is an area of active research. A number of recent studies has aimed at expanding the reach of rotational control to extreme, previously inaccessible rotational states, as well as controlling the…

Quantum Physics · Physics 2015-01-13 V. Milner , J. W. Hepburn

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

Quantum tracking control aims to identify applied fields to steer the expectation values of particular observables along desired paths in time. The associated temporal fields can be identified by inverting the underlying dynamical equations…

Quantum Physics · Physics 2018-10-31 Alicia Magann , Tak-San Ho , Herschel Rabitz

The non-linear optimization method developed by Konnov and Krotov [Automation and Remote Control 60, 1427 (1999)] has been used previously to extend the capabilities of optimal control theory from the linear to the non-linear Schr\"odinger…

Quantum Physics · Physics 2012-03-13 Daniel Reich , Mamadou Ndong , Christiane P. Koch

We propose a new formulation of optimal and local control algorithms which enforces the constraint of time-integrated zero-area on the control field. The fulfillment of this requirement, crucial in many physical applications, is…

Quantum Physics · Physics 2015-06-22 D. Sugny , S. Vranckx , M. Ndong , O. Atabek , M. Desouter-Lecomte

Short laser pulses are widely used for controlling molecular rotational degrees of freedom and inducing molecular alignment, orientation, unidirectional rotation and other types of coherent rotational motion. To follow the ultra-fast…

Starting from an initial pure quantum state, we present a strategy for reaching a target state corresponding to the extremum (maximum or minimum) of a given observable. We show that a sequence of pulses of moderate intensity, applied at…

Quantum Physics · Physics 2016-08-16 D. Sugny , A. Keller , O. Atabek , D. Daems , C. M. Dion , S. Guérin , H. R. Jauslin

Quantum controls realize the unitary or nonunitary operations employed in quantum computers, quantum simulators, quantum communications, and other quantum information devices. They implement the desired quantum dynamics with the help of…

Quantum Physics · Physics 2022-06-02 T S Mahesh , Priya Batra , M. Harshanth Ram

Optimal control theory is usually formulated as an indirect method requiring the solution of a two-point boundary value problem. Practically, the solution is obtained by iterative forward and backward propagation of quantum wavepackets.…

Quantum Physics · Physics 2020-10-09 Alejandro R. Ramos Ramos , Oliver Kühn

Optimizing the controls of quantum systems plays a crucial role in advancing quantum technologies. The time-varying noises in quantum systems and the widespread use of inhomogeneous quantum ensembles raise the need for high-quality quantum…

Quantum Physics · Physics 2025-05-06 Xinyu Fei , Lucas T. Brady , Jeffrey Larson , Sven Leyffer , Siqian Shen

We present a combined analytical and numerical investigation to show how an optimal control field can be designed to generate maximum field-free orientation of molecules for three populated rotational states. Based on a model involving pure…

Quantum Physics · Physics 2021-07-28 Qian-Qian Hong , Li-Bao Fan , Chuan-Cun Shu , Niels E. Henriksen

We propose the use of mixing strategies to accelerate the convergence of the common iterative algorithms utilized in Quantum Optimal Control Theory (QOCT). We show how the non-linear equations of QOCT can be viewed as a "fixed-point"…

Computational Physics · Physics 2009-03-31 Alberto Castro , E. K. U. Gross