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We analyze the robustness of decoherence-free (DF) subspace and subsystem in charge qubits, when difference from the collective decoherence measurement condition is large in the long time period, which is applicable for solid-state qubits…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Tetsufumi Tanamoto , Shinobu Fujita

We formulate an effective-description framework for the dynamics of open quantum systems by extending the time-coarse-graining formalism to open systems. Our coarse-graining procedure efficiently removes high-frequency processes which are…

Quantum Physics · Physics 2018-01-17 Chang-Woo Lee , Changsuk Noh , Jaewan Kim

In this work we find explicitly the decoherence free subspace (DFS) for a two two-level system in a common squeezed vacuum bath. We also find an orthogonal basis for the DFS composed of a symmetrical and an antisymmetrical (under particle…

Quantum Physics · Physics 2009-11-13 D. Mundarain , M. Orszag

We discuss the use of incoherent light as a resource to control the atomic dynamics and review the proposed in Phys. Rev. A 84, 042106 (2011) method for a controlled transfer between any pure and mixed states of quantum systems using a…

Quantum Physics · Physics 2012-12-12 Alexander Pechen

Reducing decoherence is an essential step toward realizing general-purpose quantum computers beyond the present noisy intermediate-scale quantum (NISQ) computers. To this end, dynamical decoupling (DD) approaches in which external fields…

Quantum Physics · Physics 2022-09-23 Yukiyoshi Ohtsuki , Suicho Mikami , Toru Ajiki , David J. Tannor

We show lasing without population inversion in a closed four-level atomic system which is no longer incoherently pumped on the transition at which lasing occurs. The four-level system can overcome some limits in the typical lambda-type and…

Quantum Physics · Physics 2007-05-23 Li-Feng Cai

Understanding the interplay between a quantum system and its environment lies at the heart of quantum science and its applications. To-date most efforts have focused on circumventing decoherence induced by the environment by either…

We present detailed analysis of the convergence properties and effectiveness of Lyapunov control design for bilinear Hamiltonian quantum systems based on the application of LaSalle's invariance principle and stability analysis from…

Quantum Physics · Physics 2009-10-01 Xiaoting Wang , Sonia Schirmer

We show how to efficiently exploit decoherence free subspaces (DFSs), which are immune to collective noise, for realizing quantum repeaters with long lived quantum memories. Our setup consists of an assembly of simple modules and we show…

Quantum Physics · Physics 2007-05-23 Alexander Klein , Uwe Dorner , Carolina Moura Alves , Dieter Jaksch

Quantum control of an open system is demonstrated employing a thermodynamically consistent master equation. In this framework, the open system dynamics depend on the control protocol due to the dressing of the system by the drive. This…

Quantum Physics · Physics 2022-09-16 Shimshon Kallush , Roie Dann , Ronnie Kosloff

We apply the time-dependent decoherence-free subspace theory to a Markovian open quantum system in order to present a novel proposal for quantum-state engineering program. By quantifying the purity of the quantum state, we verify that the…

Quantum Physics · Physics 2015-06-24 S. L. Wu

Coherence in an open quantum system is degraded through its interaction with a bath. This decoherence can be avoided by restricting the dynamics of the system to special decoherence-free subspaces. These subspaces are usually constructed…

Quantum Physics · Physics 2016-09-08 Daniel A. Lidar , Dave Bacon , Julia Kempe , K. B. Whaley

The dynamics of an atomic few-level system can depend on the phase of driving fields coupled to the atom if certain conditions are satisfied. This is of particular interest to control interference effects, which can alter the system…

Quantum Physics · Physics 2009-11-11 Joerg Evers

Nonadiabatic geometric quantum computation in decoherence-free subspaces has received increasing attention due to the merits of its high-speed implementation and robustness against both control errors and decoherence. However, all the…

Quantum Physics · Physics 2017-01-04 P. Z. Zhao , G. F. Xu , D. M. Tong

The relaxation dynamics of an open quantum system is determined by the competition between the coherent Hamiltonian dynamics of a system and the dissipative dynamics due to interactions with environments. It is therefore of fundamental…

Quantum Physics · Physics 2023-12-25 Taiki Haga , Masaya Nakagawa , Ryusuke Hamazaki , Masahito Ueda

Quantum systems with a large number of fermionic degrees of freedom are intractable by quantum simulations. In this paper we introduce the concept of a dedicated quantum simulator(DQS) which is an artificial system of quantum dots whose…

Strongly Correlated Electrons · Physics 2010-01-21 Efstratios Manousakis

The successful application of Quantum Optimal Control (QOC) over the past decades unlocked the possibility of directing the dynamics of quantum systems. Nevertheless, solutions obtained from QOC algorithms are usually highly irregular,…

Quantum Physics · Physics 2020-02-26 Martin Larocca , Esteban A. Calzetta , Diego A. Wisniacki

Manipulate and control of the complex quantum system with high precision are essential for achieving universal fault tolerant quantum computing. For a physical system with restricted control resources, it is a challenge to control the…

Quantum Physics · Physics 2021-01-20 Zheng An , Qi-Kai He , Hai-Jing Song , D. L. Zhou

Control of quantum dissipative systems can be challenging because control variables are typically part of the system Hamiltonian, which can only generate motion along unitary orbits of the system. To transit between orbits, one must harness…

Quantum Physics · Physics 2012-01-04 Patrick Rooney , Anthony Bloch , Chitra Rangan

Quantum error-correcting codes (QECCs) and decoherence-free subspace (DFS) codes provide active and passive means, respectively, to address certain types of errors that arise during quantum computation. The latter technique is suitable to…

Quantum Physics · Physics 2024-07-02 Nihar Ranjan Dash , Sanjoy Dutta , R. Srikanth , Subhashish Banerjee