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A general strategy to maintain the coherence of a quantum bit is proposed. The analytical result is derived rigorously including all memory and back-action effects. It is based on an optimized $\pi$-pulse sequence for dynamic decoupling…

Quantum Physics · Physics 2011-11-09 Götz S. Uhrig

We construct efficient deterministic dynamical decoupling schemes protecting continuous variable degrees of freedom. Our schemes target decoherence induced by quadratic system-bath interactions with analytic time-dependence. We show how to…

Quantum Physics · Physics 2019-07-16 Margret Heinze , Robert Koenig

Constructing high-fidelity control fields that are robust to control, system, and/or surrounding environment uncertainties is a crucial objective for quantum information processing. Using the two-state Landau-Zener model for illustrative…

Quantum Physics · Physics 2012-05-23 Matthew D. Grace , Jason Dominy , Wayne M. Witzel , Malcolm S. Carroll

We explore the physical limits of pulsed dynamical decoupling methods for decoherence control as determined by finite timing resources. By focusing on a decohering qubit controlled by arbitrary sequences of $\pi$-pulses, we establish a…

Quantum Physics · Physics 2011-04-11 Kaveh Khodjasteh , Tamás Erdélyi , Lorenza Viola

Quantum computers, which process information encoded in quantum mechanical systems, hold the potential to solve some of the hardest computational problems. A substantial obstacle for the further development of quantum computers is the fact…

Quantum Physics · Physics 2012-11-02 Alexandre M. Souza , Gonzalo A. Álvarez , Dieter Suter

We investigate the optimal dynamical decoupling sequence for a qubit coupled to an ohmic environment. By analytically computing the derivatives of the decoherence function, the optimal pulse locations are found to satisfy a set of nonlinear…

Quantum Physics · Physics 2010-09-21 Yu Pan , Zairong Xi , Wei Cui

For a generic dynamical decoupling sequence employing a single-axis control, we study its efficiency in the presence of small errors in direction of the controlling-pulses. In the case that the corresponding ideal dynamical-decoupling…

Quantum Physics · Physics 2013-05-29 Zhihao Xiao , Lewei He , Wen-ge Wang

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

We study the suppression of qubit dephasing through Uhrig dynamical decoupling (UDD) in nontrivial environments modeled within the spin-boson formalism. In particular, we address the case of (i) a qubit coupled to a bosonic bath with…

Quantum Physics · Physics 2017-01-06 W. S. Teixeira , K. T. Kapale , M. Paternostro , F. L. Semião

An optimal dynamical decoupling of a quantum system coupled to a noisy environment must take into account also the imperfections of the control pulses. We present a new formalism which describes, in a closed-form expression, the evolution…

Quantum Physics · Physics 2016-10-19 Ido Almog , Gil Loewenthal , Jonathan Coslovsky , Yoav Sagi , Nir Davidson

A general coherent control scenario to suppress, or accelerate, tunneling of quantum states decaying into a continuum, is investigated. The method is based on deterministic, or stochastic, sequences of unitary pulses that affect the…

Quantum Physics · Physics 2010-09-09 Rajdeep Saha , Victor S. Batista

Dynamical decoupling can be used to preserve arbitrary quantum states despite undesired interactions with the environment, using control Hamiltonians affecting the system only. We present a system-independent analysis of dynamical…

Quantum Physics · Physics 2009-11-13 Kaveh Khodjasteh , Daniel A. Lidar

We investigate the effectiveness of different dynamical decoupling protocols for storage of a single qubit in the presence of a purely dephasing bosonic bath, with emphasis on comparing quantum coherence preservation under uniform vs.…

Quantum Physics · Physics 2015-05-14 Thomas E. Hodgson , Lorenza Viola , Irene D'Amico

We present a detailed experimental study of the Uhrig Dynamical Decoupling (UDD) sequence in a variety of noise environments. Our qubit system consists of a crystalline array of $^{9}$Be$^{+}$ ions confined in a Penning trap. We use an…

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 propose a methodology to design optimal pulses for achieving quantum optimal control on molecular systems. Our approach constrains pulse shapes to linear combinations of a fixed number of experimentally relevant pulse functions. Quantum…

Quantum Physics · Physics 2015-10-28 Ruben D. Guerrero , Carlos A. Arango , Andres Reyes

Stroboscopic spin flips have already been shown to prolong the coherence times of quantum systems under noisy environments. Uhrig's dynamical decoupling scheme provides an optimal sequence for a quantum system interacting with a dephasing…

Quantum Physics · Physics 2011-10-10 Soumya Singha Roy , T. S. Mahesh , G. S. Agarwal

We present an efficient strategy for controlling a vast range of non-integrable quantum many body one-dimensional systems that can be merged with state-of-the-art tensor network simulation methods like the density Matrix Renormalization…

Quantum Physics · Physics 2015-03-13 Patrick Doria , Tommaso Calarco , Simone Montangero

Dynamical decoupling pulse sequences have been used to extend coherence times in quantum systems ever since the discovery of the spin-echo effect. Here we introduce a method of recursively concatenated dynamical decoupling pulses, designed…

Quantum Physics · Physics 2007-05-23 K. Khodjasteh , D. A. Lidar

Pulse controlled non-adiabatic quantum state transmission (QST) was proposed many years ago. However, in practice environmental noise inevitably damages communication quality in the proposal. In this paper, we study the optimally controlled…

Quantum Physics · Physics 2023-09-26 Xiang-Han Liang , Lian-Ao Wu , Zhao-Ming Wang