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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 study the selective and robust time-optimal rotation control of several spin-1/2 particles with different offset terms. For that purpose, the Pontryagin Maximum Principle is applied to a model of two spins, which is simple enough for…

Quantum Physics · Physics 2021-02-09 Quentin Ansel , Steffen J. Glaser , Dominique Sugny

Zero-field nuclear magnetic resonance (NMR) provides complementary analysis modalities to those of high-field NMR and allows for ultra-high-resolution spectroscopy and measurement of untruncated spin-spin interactions. Unlike for the…

Quantum Physics · Physics 2022-03-01 Min Jiang , Teng Wu , John W. Blanchard , Guanru Feng , Xinhua Peng , Dmitry Budker

Most quantum processors requires pulse sequences for controlling quantum states. Here, we present an alternative algorithm for computing an optimal pulse sequence in order to perform a specific task, being an implementation of a quantum…

Quantum Physics · Physics 2020-05-27 John P. S. Peterson , Roberto S. Sarthour , Raymond Laflamme

In order to achieve the high-fidelity quantum control needed for a broad range of quantum information technologies, reducing the effects of noise and system inhomogeneities is an essential task. It is well known that a system can be…

Mesoscale and Nanoscale Physics · Physics 2019-01-30 Junkai Zeng , Xiu-Hao Deng , Antonio Russo , Edwin Barnes

Numerically optimised microwave pulses are used to increase excitation efficiency and modulation depth in electron spin resonance experiments performed on a spectrometer equipped with an arbitrary waveform generator. The optimisation…

Chemical Physics · Physics 2018-10-19 David L. Goodwin , William K. Myers , Christiane R. Timmel , Ilya Kuprov

Spin squeezing has been explored in atomic systems as a tool for quantum sensing, improving experimental sensitivity beyond the spin standard quantum limit for certain measurements. To optimize absolute metrological sensitivity, it is…

High Energy Physics - Phenomenology · Physics 2025-02-21 Eric Boyers , Garry Goldstein , Alexander O. Sushkov

We describe a method for improving coherent control through the use of detailed knowledge of the system's Hamiltonian. Precise unitary transformations were obtained by strongly modulating the system's dynamics to average out unwanted…

Magnetic resonance (MR) fingerprinting is a new quantitative imaging paradigm, which simultaneously acquires multiple MR tissue parameter maps in a single experiment. In this paper, we present an estimation-theoretic framework to perform…

Signal Processing · Electrical Eng. & Systems 2018-10-03 Bo Zhao , Justin P. Haldar , Congyu Liao , Dan Ma , Yun Jiang , Mark A. Griswold , Kawin Setsompop , Lawrence L. Wald

Detecting and controlling nuclear spin nano-ensembles is crucial for the further development of nuclear magnetic resonance (NMR) spectroscopy and for the emerging solid state quantum technology. Here we present the fabrication of a…

We present an open-source software for the simulation of observables in magnetic resonance experiments, including nuclear magnetic/quadrupole resonance NMR/NQR and electron spin resonance (ESR), developed to assist experimental research in…

We present a continuous-time, neural-network-based approach to optimal control in quantum systems, with a focus on pulse engineering for quantum gates. Leveraging the framework of neural ordinary differential equations, we construct control…

In this work, we investigate how and to which extent a quantum system can be driven along a prescribed path in Hilbert space by a suitably shaped laser pulse. To calculate the optimal, i.e., the variationally best pulse, a properly defined…

Quantum Physics · Physics 2007-05-23 I. Serban , J. Werschnik , E. K. U. Gross

Numerical modelling of coherent spin relaxation in nanomagnets, formed by magnetic molecules of high spins, is accomplished. Such a coherent spin dynamics can be realized in the presence of a resonant electric circuit coupled to the magnet.…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 V. I. Yukalov , V. K. Henner , P. V. Kharebov

Relaxation effects impose fundamental limitations on our ability to coherently control quantum mechanical phenomena. In this letter, we establish physical limits on how closely can a quantum mechanical system be steered to a desired target…

Quantum Physics · Physics 2009-11-10 N. Khaneja , B. Luy , S. J. Glaser

Initially introduced in the framework of quantum control, the so-called "monotonic algorithms" have demonstrated excellent numerical performance when dealing with bilinear optimal control problems. This paper presents a unified formulation…

Optimization and Control · Mathematics 2010-11-11 Julien Salomon , Gabriel Turinici

The theory of optimal quantum control serves to identify time-dependent control Hamiltonians that efficiently produce desired target states. As such, it plays an essential role in the successful design and development of quantum…

Quantum Physics · Physics 2023-04-18 Tenzan Araki , Franco Nori , Clemens Gneiting

Many applications of magnetic resonance are limited by rapid loss of spin coherence caused by large transverse relaxation rates. In nuclear magnetic resonance (NMR) of large proteins, increased relaxation losses lead to poor sensitivity of…

Quantum Physics · Physics 2007-05-23 N. Khaneja , J. S. Li , C. Kehlet , B. Luy , S. J. Glaser

Over recent decades, the value of conducting experiments at lower frequencies and in inhomogeneous and/or time-variable fields has grown. For example, an interest in the nanoscale heterogeneities of hydration dynamics demands increasingly…

Chemical Physics · Physics 2022-11-23 Alec A. Beaton , Alexandria Guinness , John M. Franck

We address a problem of generating a robust entangling gate between electronic and nuclear spins in the system of a single nitrogen-vacany centre coupled to a nearest Carbon-13 atom in diamond against certain types of systematic errors such…

Quantum Physics · Physics 2010-07-14 R. S. Said , J. Twamley