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Numerically we simulate the effect of optimized coherent control pulses with a finite duration on a qubit in a bath of spins. The pulses of finite duration are compared with ideal instantaneous pulses. In particular, we show that properly…

Quantum Physics · Physics 2008-08-26 P. Karbach , S. Pasini , G. S. Uhrig

We investigate the maximum signal to noise ratio per unit time that can be achieved for a spin 1/2 particle subjected to a periodic pulse sequence. Optimal control techniques are applied to design the control field and the position of the…

Quantum Physics · Physics 2015-06-22 M. Lapert , E. Assémat , S. J. Glaser , D. Sugny

In the burgeoning field of quantum computing, the precise design and optimization of quantum pulses are essential for enhancing qubit operation fidelity. This study focuses on refining the pulse engineering techniques for superconducting…

Quantum Physics · Physics 2024-09-13 Annika S. Wiening , Joern Bergendahl , Vicente Leyton-Ortega , Peter Nalbach

We demonstrate significant improvements of the spin coherence time of a dense ensemble of nitrogen-vacancy (NV) centers in diamond through optimized dynamical decoupling (DD). Cooling the sample down to $77$ K suppresses longitudinal spin…

Model-based deep learning methods that combine imaging physics with learned regularization priors have been emerging as powerful tools for parallel MRI acceleration. The main focus of this paper is to determine the utility of the monotone…

Machine Learning · Computer Science 2023-04-05 Aniket Pramanik , Mathews Jacob

The ability to characterise a Hamiltonian with high precision is crucial for the implementation of quantum technologies. In addition to the well-developed approaches utilising optimal probe states and optimal measurements, the method of…

Quantum Physics · Physics 2022-12-14 Shushen Qin , Marcus Cramer , Christiane P. Koch , Alessio Serafini

We discuss the implementation of arbitrary precision composite pulses developed using the methods of Brown et al. [Phys. Rev. A 70 (2004) 052318]. We give explicit results for pulse sequences designed to tackle both the simple case of pulse…

Quantum Physics · Physics 2007-11-05 William G. Alway , Jonathan A. Jones

We develop an hybrid quantum-classical algorithm to solve an optimal population transfer problem for a molecule subject to a laser pulse. The evolution of the molecular wavefunction under the laser pulse is simulated on a quantum computer,…

Quantum Physics · Physics 2021-02-25 Davide Castaldo , Marta Rosa , Stefano Corni

Composite pulses are essential for universal manipulation of singlet-triplet spin qubits. In the absence of noise, they are required to perform arbitrary single-qubit operations due to the special control constraint of a singlet-triplet…

Quantum Physics · Physics 2018-04-18 Xu-Chen Yang , Man-Hong Yung , Xin Wang

As quantum control approaches hardware-imposed performance limits, weak effects omitted by reduced models become consequential. Assumptions required for analytic tractability then cease to guide control design and instead constrain further…

Computational imaging has been revolutionized by compressed sensing algorithms, which offer guaranteed uniqueness, convergence, and stability properties. Model-based deep learning methods that combine imaging physics with learned…

Computer Vision and Pattern Recognition · Computer Science 2023-03-01 Aniket Pramanik , M. Bridget Zimmerman , Mathews Jacob

Nuclear magnetic resonance offers an appealing prospect for implementation of quantum computers, because of the long coherence times associated with nuclear spins, and extensive laboratory experience in manipulating the spins with radio…

Quantum Physics · Physics 2007-05-23 Leonard J. Schulman , Umesh Vazirani

We provide a technique to obtain provably optimal control sequences for quantum systems under the influence of time-correlated multiplicative control noise. Utilizing the circuit-level noise model introduced in [Phys. Rev. Research 3,…

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

Magnetic Resonance Imaging (MRI) is one of the most dynamic and safe imaging techniques available for clinical applications. However, the rather slow speed of MRI acquisitions limits the patient throughput and potential indi cations.…

Computer Vision and Pattern Recognition · Computer Science 2018-11-14 Risheng Liu , Yuxi Zhang , Shichao Cheng , Xin Fan , Zhongxuan Luo

Coherent pulse control for quantum memory is viable in the optical domain but nascent in microwave quantum circuits. We show how to realize coherent storage and on-demand pulse retrieval entirely within a superconducting circuit by…

Quantum Physics · Physics 2015-03-20 Patrick M. Leung , Barry C. Sanders

A long-standing problem in quantum optimal control is finding an optimal pulse structure that leads to an efficient exploration of the unitary space with a minimal number of optimization parameters. We solve this problem by constructing…

We introduce a novel control method for robust quantum information processing suited for quantum integrated photonics. We utilize off-resonant detunings as control parameters to derive a new family of composite pulses for high-fidelity…

Quantum Physics · Physics 2019-10-02 Elica Kyoseva , Hadar Greener , Haim Suchowski

A recent quantum computing paper (G. S. Uhrig, Phys Rev Lett 98 100504 (2007)) analytically derived optimal pulse spacings for a multiple spin echo sequence designed to remove decoherence in a two level system coupled to a bath. The…

Chemical Physics · Physics 2015-05-14 Elizabeth Jenista , Ashley Stokes , Rosa Branca , Warren Warren

In this paper, we study some control problems that derive from time optimal control of coupled spin dynamics in NMR spectroscopy and quantum information and computation. Time optimal control helps to minimize relaxation losses. The ability…

Quantum Physics · Physics 2017-09-05 Navin Khaneja