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In this report, we examine the decoherence of a spin qubits system coupled to counted spin chain with a $1/r^2$ interaction by using influence functional. We also examine the time evolution of density matrix numerically when environment is…

Mesoscale and Nanoscale Physics · Physics 2008-12-20 Toshifumi Itakura

The prospect of developing magnetic qubits is discussed. The first part of the article makes suggestions on how to achieve the coherent quantum superposition of spin states in small ferromagnetic clusters, weakly uncompensated…

Statistical Mechanics · Physics 2007-05-23 Eugene M. Chudnovsky

The study of decoherence plays a key role in our understanding of the transition from the quantum to the classical world. Typically, one considers a system coupled to an external bath which forms a model for an open quantum system. While…

Quantum Physics · Physics 2024-04-24 Suraka Bhattacharjee , Koushik Mandal , Supurna Sinha

We analyze the effect of a bath of spins interacting with a spin system in terms of the equation of motion technique. We show that this formalism can be used with general spin systems and baths, and discuss the concrete case of a Quantum…

Strongly Correlated Electrons · Physics 2019-09-23 Álvaro Gómez-León , Tim Cox , Philip Stamp

We present a study of the effects of decoherence in the operation of a discrete quantum walk on a line, cycle and hypercube. We find high sensitivity to decoherence, increasing with the number of steps in the walk, as the particle is…

Quantum Physics · Physics 2009-11-07 Viv Kendon , Ben Tregenna

For the prototypical example of the Ising chain in a transverse field, we study the impact of decoherence on the sweep through a second-order quantum phase transition. Apart from the advance in the general understanding of the dynamics of…

Quantum Physics · Physics 2007-09-17 Sarah Mostame , Gernot Schaller , Ralf Schützhold

"Decoherence of quantum superpositions through coupling to engineered reservoirs" is the topic of a recent article by Myatt et al. [Nature {\underline{403}}, 269 (2000)] which has attracted much interest because of its relevance to current…

Quantum Physics · Physics 2009-11-10 R. F. O'Connell , Jian Zuo

The decoherence mechanism of a single atom inside a high-Q cavity is studied, and the results are compared with experimental observations performed by M. Brune et al. [Phys. Rev. Lett. 76, 1800 (1996)]. Collision dephasing and cavity…

Quantum Physics · Physics 2009-11-10 T. W. Chen , P. T. Leung

We present an open loop (bang-bang) scheme to control decoherence in a generic one-qubit quantum gate and implement it in a realistic simulation. The system is consistently described within the spin-boson model, with interactions accounting…

Quantum Physics · Physics 2009-11-07 V. Protopopescu , R. Perez , C. D'Helon , J. Schmulen

In the effort to design and to construct a quantum computer, several leading proposals make use of spin-based qubits. These designs generally assume that spins undergo pairwise interactions. We point out that, when several spins are engaged…

Quantum Physics · Physics 2009-11-10 Ari Mizel , Daniel A. Lidar

This work proposes a series of quantum experiments that can, at least in principle, allow for examining microscopic mechanisms associated with decoherence. These experiments can be interpreted as a quantum-mechanical version of…

Quantum Physics · Physics 2021-09-21 A. Y. Klimenko

We study the decoherence of a quantum computer in an environment which is inherently correlated in time and space. We first derive the nonunitary time evolution of the computer and environment in the presence of a stabilizer error…

Quantum Physics · Physics 2007-05-23 E. Novais , Harold U. Baranger

In addition to being a very interesting quantum phenomenon, Schr\"odinger cat swapping has the potential for application in the preparation of quantum states that could be used in metrology and other quantum processing. We study in detail…

Quantum Physics · Physics 2012-03-01 M. J. Everitt , W. J. Munro , T. P. Spiller

In this work, we consider decoherence of a central spin by a spin bath. In order to study the non-perturbative decoherence regimes, we develop an efficient mean-field-based method for modeling the spin-bath decoherence, based on the…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 K. A. Al-Hassanieh , V. V. Dobrovitski , E. Dagotto , B. N. Harmon

This paper describes the dynamics of a quantum two-level system (qubit) under the influence of an environment modeled by an ensemble of random matrices. In distinction to earlier work, we consider here separable couplings and focus on a…

Quantum Physics · Physics 2015-06-19 M. Carrera , T. Gorin , T. H. Seligman

The key feature of a quantum spin coupled to a harmonic bath---a model dissipative quantum system---is competition between oscillator potential energy and spin tunneling rate. We show that these opposing tendencies cause environmental…

Quantum Physics · Physics 2014-03-21 Soumya Bera , Serge Florens , Harold U. Baranger , Nicolas Roch , Ahsan Nazir , Alex W. Chin

We study the interaction of a two-level atom and two fields, one of them classical. We obtain an effective Hamiltonian for this system by using a method recently introduced that produces a small rotation to the Hamiltonian that allows to…

Quantum Physics · Physics 2013-12-04 R. Juárez-Amaro , J. L. Escudero-Jiménez , H. Moya-Cessa

The dynamics of a dimer coupled to two different environments each in a spin star configuration under the influence of decoherence is studied. The exact analytical expression for the transition probability in the dimer system is obtained…

Quantum Physics · Physics 2014-01-15 I. Sinayskiy , A. Marais , F. Petruccione , A. Ekert

We consider spin effects related to the random spin-orbit interaction in graphene. Such a random interaction can result from the presence of ripples and/or other inhomogeneities at the graphene surface. We show that the random spin-orbit…

Mesoscale and Nanoscale Physics · Physics 2015-05-20 V. K. Dugaev , E. Ya. Sherman , J. Barnas

Spin qubits are at the heart of technological advances in quantum processors and offer an excellent framework for quantum information processing. This work characterizes the time evolution of coherence and nonclassical correlations in a…

Quantum Physics · Physics 2023-04-13 Zakaria Dahbi , Mansoura Oumennana , Mostafa Mansour