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We study time-optimal protocols for controlling quantum systems which show several avoided level crossings in their energy spectrum. The structure of the spectrum allows us to generate a robust guess which is time-optimal at each crossing.…

Quantum Physics · Physics 2015-11-18 P. M. Poggi , F. C. Lombardo , D. A. Wisniacki

We show that if an efficient classical representation of the dynamics exists, optimal control problems on many-body quantum systems can be solved efficiently with finite precision. We show that the size of the space of parameters necessary…

Quantum Physics · Physics 2014-07-09 S. Lloyd , S. Montangero

We present a numerical method to simulate the time evolution, according to a Hamiltonian made of local interactions, of quantum spin chains and systems alike. The efficiency of the scheme depends on the amount of the entanglement involved…

Quantum Physics · Physics 2009-11-10 G. Vidal

Pulses to steer the time evolution of quantum systems can be designed with optimal control theory. In most cases it is the coherent processes that can be controlled and one optimizes the time evolution towards a target unitary process,…

Quantum Physics · Physics 2015-06-22 Daniel J. Egger , Frank K. Wilhelm

We present a numerically tractable formulation for computing the optimal control of the class of hybrid dynamical systems whose trajectories are continuous. Our formulation, an extension of existing relaxed-control techniques for switched…

Optimization and Control · Mathematics 2016-05-26 Tyler Westenbroek , Humberto Gonzalez

Achieving high-fidelity control of quantum systems is essential for realization of a practical quantum computer. Composite pulse sequences which suppress different types of errors can be nested to suppress a wide variety of errors but the…

Mesoscale and Nanoscale Physics · Physics 2019-12-09 Utkan Güngördü , J. P. Kestner

The goal of this paper is to solve a class of stochastic optimal control problems numerically, in which the state process is governed by an It\^o type stochastic differential equation with control process entering both in the drift and the…

Optimization and Control · Mathematics 2020-06-05 Richard Archibald , Feng Bao , Jiongmin Yong , Tao Zhou

A new class of cost functionals for optimal control of quantum systems which produces controls which are sparse in frequency and smooth in time is proposed. This is achieved by penalizing a suitable time-frequency representation of the…

Optimization and Control · Mathematics 2016-07-15 Gero Friesecke , Felix Henneke , Karl Kunisch

In the era of Noisy Intermediate-Scale Quantum computing as well as in error correcting circuits, physical qubits coherence time and high fidelity gates are essential to the functioning of quantum computers. In this paper, we demonstrate…

Quantum Physics · Physics 2024-08-27 Max Cykiert , Eran Ginossar

Existing algorithms for the optimal control of quantum observables are based on locally optimal steps in the space of control fields, or as in the case of genetic algorithms, operate on the basis of heuristics that do not explicitly take…

Quantum Physics · Physics 2007-08-27 Raj Chakrabarti , Rebing Wu , Herschel Rabitz

Efficient optical quantum memories are a milestone required for several quantum technologies including repeater-based quantum key distribution and on-demand multi-photon generation. We present an efficiency optimization of an optical…

Quantum Physics · Physics 2024-01-11 Elizabeth Robertson , Luisa Esguerra , Leon Messner , Guillermo Gallego , Janik Wolters

The past decade has demonstrated increasing interests in using optimal control based methods within coherent quantum controllable systems. The versatility of such methods has been demonstrated with particular elegance within nuclear…

Quantum Physics · Physics 2015-05-18 Ivan I. Maximov , Niels Chr. Nielsen , Julien Salomon , Gabriel Turinici

We present efficient quantum algorithms for simulating time-dependent Hamiltonian evolution of general input states using an oracular model of a quantum computer. Our algorithms use either constant or adaptively chosen time steps and are…

Quantum Physics · Physics 2011-11-03 Nathan Wiebe , Dominic W. Berry , Peter Hoyer , Barry C. Sanders

We propose a method to compute optimal control paths for autonomous vehicles deployed for the purpose of inferring a velocity field. In addition to being advected by the flow, the vehicles are able to effect a fixed relative speed with…

Optimization and Control · Mathematics 2015-12-09 Damon McDougall , Richard Moore

We describe a simple quantum algorithm to simulate time-dependent Hamiltonian, extending the methodology of quantum signal processing. The framework achieves optimal scaling up to some factor with respect to other parameters, and nearly…

Quantum Physics · Physics 2025-03-11 Nhat A. Nghiem

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 study a stochastic control problem for continuous multidimensional martingales with fixed quadratic variation. In a radially symmetric environment, we are able to find an explicit solution to the control problem and find an optimal…

Probability · Mathematics 2025-06-10 Alexander M. G. Cox , Benjamin A. Robinson

We present an approach to compute time-optimal control of a quantum system which combines quantum brachistochrone and Lax pair techniques and enables efficient investigation of large-scale quantum systems. We illustrate our method by…

Quantum Physics · Physics 2025-11-17 Andrei A. Stepanenko , Kseniia S. Chernova , Maxim A. Gorlach

Optimal control theory provides a framework for numerical discovery of device controls that implement quantum logic gates, but common objective functions used for optimization often assign arbitrarily high costs to otherwise useful…

Quantum Physics · Physics 2021-10-07 Paul Kairys , Travis S. Humble

Several methods are proposed for the analysis, visualization and interpretation of high-dimensional spin system trajectories produced by quantum mechanical simulations. It is noted that expectation values of specific observables in large…

Quantum Physics · Physics 2014-07-16 Ilya Kuprov