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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

Terminal sliding mode (TSM) control algorithm and its non-singular refinement have been elaborated for two decades and belong, since then, to a broader class of the finite-time controllers, which are known to be robust against the matched…

Systems and Control · Electrical Eng. & Systems 2021-03-24 Michael Ruderman

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

We demonstrate two simple theorems about squeezing induced by bilinear spin-spin interactions that conserve spin parity -- including a vast majority of quantum spin models implemented by state-of-the-art quantum simulators. In particular we…

Quantum Physics · Physics 2021-11-10 Tommaso Roscilde , Fabio Mezzacapo , Tommaso Comparin

We investigate optimal reachability and grasping problems for a planar soft manipulator, from both a theoretical and numerical point of view. The underlying control model describes the evolution of the symmetry axis of the device, which is…

Optimization and Control · Mathematics 2020-02-14 Simone Cacace , Anna Chiara Lai , Paola Loreti

With recent improvements in coherence times, superconducting transmon qubits have become a promising platform for quantum computing. They can be flexibly engineered over a wide range of parameters, but also require us to identify an…

Quantum Physics · Physics 2017-09-21 Michael H. Goerz , Felix Motzoi , K. Birgitta Whaley , Christiane P. Koch

Quantum sensors can show unprecedented sensitivities, provided they are controlled in a very specific, optimal way. Here, we consider a spin sensor of time-varying fields in the presence of dephasing noise, and we show that the problem of…

Quantum Physics · Physics 2024-07-10 S. Hernández-Gómez , F. Balducci , G. Fasiolo , P. Cappellaro , N. Fabbri , A. Scardicchio

We develop a methodology for performing approximate optimal control simulations for quantum systems with multiple interacting degrees of freedom. The quantum dynamics are modeled using the first-order Magnus approximation in the interaction…

Quantum Physics · Physics 2020-08-05 Andrew Ma , Alicia B. Magann , Tak-San Ho , Herschel Rabitz

Ramsey spectroscopy has become a powerful technique for probing non-equilibrium dynamics of internal (pseudospin) degrees of freedom of interacting systems. In many theoretical treatments, the key to understanding the dynamics has been to…

Atomic Physics · Physics 2015-06-18 A. P. Koller , M. Beverland , A. V. Gorshkov , A. M. Rey

This paper introduces a novel approach to the optimal control of linear discrete-time systems subject to bounded disturbances. Our approach is based on the newly established duality between ellipsoidal approximations of reachable and hardly…

Systems and Control · Electrical Eng. & Systems 2024-09-20 Egor Dogadin , Alexey Peregudin , Dmitriy Shirokih

Spin squeezing can increase the sensitivity of interferometric measurements of small signals in large spin ensembles beyond the standard quantum limit. In many practical settings, the ideal metrological gain is limited by imperfect readout…

Quantum Physics · Physics 2024-07-02 Martin Koppenhöfer , A. A. Clerk

Quantum metrology experiments in atomic physics and quantum optics have demonstrated measurement accuracy beyond the shot-noise limit via multi-particle entanglement. At the same time, electron microscopy, an essential tool for…

Recent work has shown that a simple chain of interacting spins can be used as a medium for high-fidelity quantum communication. We describe a scheme for quantum communication using a spin system that conserves z-spin, but otherwise is…

Quantum Physics · Physics 2009-11-10 Henry L. Haselgrove

Quantum entanglement is a key resource for quantum technologies, yet its efficient and high-fidelity generation remains a challenge due to the complexity of quantum dynamics. This paper presents a quantum optimal control framework to…

Quantum Physics · Physics 2025-07-15 Nahid Binandeh Dehaghani , A. Pedro Aguiar , Rafal Wisniewski

Spin-phonon coupling is the main drive of spin relaxation and decoherence in solid-state semiconductors at finite temperature. Controlling this interaction is a central problem for many disciplines, ranging from magnetic resonance to…

Materials Science · Physics 2022-08-23 Alessandro Lunghi

We investigate the performance of dynamical decoupling methods at suppressing electron spin decoherence from a low-temperature nuclear spin reservoir in a quantum dot. The controlled dynamics is studied through exact numerical simulation,…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Wenxian Zhang , V. V. Dobrovitski , Lea F. Santos , Lorenza Viola , B. N. Harmon

We determine the complete set of generalized spin squeezing inequalities. These are entanglement criteria that can be used for the experimental detection of entanglement in a system of spin-1/2 particles in which the spins cannot be…

Quantum Physics · Physics 2011-11-09 Geza Toth , Christian Knapp , Otfried Gühne , Hans J. Briegel

A mechanical system can be optimally controlled through continuous measurements of its position followed by feedback. We revisit the complete formalism for predicting the performance of such as system without invoking the standard rotating…

Quantum Physics · Physics 2023-03-01 Frederik Werner Isaksen , Ulrik Lund Andersen

In this letter, we present a constraint-driven optimal control framework that achieves emergent cluster flocking within a constrained 2D environment. We formulate a decentralized optimal control problem that includes safety, flocking, and…

Optimization and Control · Mathematics 2022-03-22 Logan E. Beaver , Andreas A. Malikopoulos

We propose a novel scheme to efficiently polarize and manipulate the electron spin in a quantum dot. This scheme is based on the spin-orbit interaction and it possesses following advantages: (1) The direction and the strength of the spin…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Qing-feng Sun , X. C. Xie