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In this article we derive the exact dynamics of a two qubit (spin 1/2) system interacting centrally with separate fermionic baths composed of qubits in thermal state. Further, each spin of a bath is coupled to every other spin of the same…

Quantum Physics · Physics 2022-10-04 Devvrat Tiwari , Shounak Datta , Samyadeb Bhattacharya , Subhashish Banerjee

Coherent many-body quantum dynamics lies at the heart of quantum simulation and quantum computation. Both require coherent evolution in the exponentially large Hilbert space of an interacting many-body system. To date, trapped ions have…

The dynamics of a simple spin chain (2 spins) coupled to bosonic baths at different temperatures is studied. The analytical solution for the reduced density matrix of the system is found. The dynamics and temperature dependence of spin-spin…

Quantum Physics · Physics 2009-05-05 Ilya Sinaysky , Francesco Petruccione , Daniel Burgarth

We study systematically the non-Markovian decoherence dynamics of a dissipative two-level system, i.e., the so-called spin-boson model. It is interesting to find that the decoherence tends to be inhibited with the increase of the coupling…

Quantum Physics · Physics 2013-06-04 Hai-Bin Liu , Jun-Hong An , Chong Chen , Qing-Jun Tong , Hong-Gang Luo , C. H. Oh

The realisation of quantum computers based on molecular electronic spins requires the design of qubits with very long coherence times, T2. Dephasing can proceed over several different microscopic pathways, active at the same time and in…

Materials Science · Physics 2020-01-08 Alessandro Lunghi , Stefano Sanvito

We study the reduced dynamics of interacting spins, each coupled to its own bath of bosons. We derive the solution in analytic form in the white-noise limit and analyze the rich behaviors in diverse limits ranging from weak coupling and/or…

Quantum Physics · Physics 2008-07-16 P. Nägele , G. Campagnano , U. Weiss

We study an analytically solvable model for decoherence of a two spin system embedded in a large spin environment. As a measure of entanglement, we evaluate the concurrence for the Bell states (Einstein-Podolsky-Rosen pairs). We find that…

Quantum Physics · Physics 2009-11-11 Zafer Gedik

We examine two exactly solvable models of decoherence -- a central spin-system, (i) with and (ii) without a self--Hamiltonian, interacting with a collection of environment spins. In the absence of a self--Hamiltonian we show that in this…

Quantum Physics · Physics 2009-11-11 F. M. Cucchietti , J. P. Paz , W. H. Zurek

A general theoretical framework for decoherence is proposed, which encompasses formalisms originally devised to deal just with open or with closed systems. The conditions for decoherence are clearly stated and the relaxation and decoherence…

Quantum Physics · Physics 2009-10-30 Mario Castagnino , Sebastian Fortin , Roberto Laura , Olimpia Lombardi

Following the recent successful formation and manipulation of entangled $C^{13}$ atoms on the surface of Diamond we calculate the decoherence of the electron spin polarization in Diamond via a nonperturbative treatment of the time-dependent…

Mesoscale and Nanoscale Physics · Physics 2011-05-06 P. R. Crompton

We study the decoherence of a coupled quantum system consisting of a central spin and its correlated environment described by a general $XY$ spin-chain model. We make it clear that the evolution of the coherence factor sensitively depends…

Quantum Physics · Physics 2014-05-06 Zi-Gang Yuan , Ping Zhang , Shu-Shen Li

We study the spin polarization of mixed and entangled electron states in a four probe/beam splitter geometry with local Rashba and Dresselhaus interactions. A pair of maximally entangled electrons collides with the beam splitter and enters…

Quantum Physics · Physics 2012-12-04 Luis A. González-Árraga , Bertrand Berche , Ernesto Medina

The article contains the description of a coherent conservation regime in the spin bath quantum decoherence model.

Quantum Physics · Physics 2020-10-01 Evgeny I. Zelenov

We study coherent spin transport through helical edge states of topological insulator tunnel-coupled to metallic leads. We demonstrate that unpolarized incoming electron beam acquires finite polarization after transmission through such a…

Mesoscale and Nanoscale Physics · Physics 2021-11-10 R. A. Niyazov , D. N. Aristov , V. Yu. Kachorovskii

We study a model of dephasing (decoherence) in a two-state quantum system (qubit) coupled to a bath of harmonic oscillators. An exact analytic solution for the reduced dynamics of a two-state system in this model has been obtained…

Quantum Physics · Physics 2015-05-28 V. G. Morozov , S. Mathey , G. Röpke

Quantum spin models with variable-range interactions can exhibit certain quantum characteristics that a short-ranged model cannot possess. By considering the quantum XYZ model whose interaction strength between different sites varies either…

Quantum Physics · Physics 2020-12-24 Leela Ganesh Chandra Lakkaraju , Srijon Ghosh , Aditi Sen De

We investigate theoretically the spin echo signal of an electron localized in a quantum dot and interacting with a bath of nuclear spins. We consider the regime of very low magnetic fields (corresponding to fields as low as a militesla in…

Mesoscale and Nanoscale Physics · Physics 2010-07-26 L. Cywinski , V. V. Dobrovitski , S. Das Sarma

Control of decoherence in open quantum systems has become a topic of great interest due to the emergence of quantum technologies that depend on quantum coherent effects. In this work, we investigate the decoherence dynamics of systems…

Quantum Physics · Physics 2025-04-04 Jitian Chen , Jakub Garwoła , Dvira Segal

We study electron-phonon interaction induced decoherence between two-electron singlet and triplet states in a semiconductor double quantum dot using a spin-boson model. We investigate the onset and time evolution of this dephasing, and…

Mesoscale and Nanoscale Physics · Physics 2015-05-20 Xuedong Hu

We compare disentanglement and decoherence rates within two-spin and three-spin entangled systems subjected to all possible combinations of local and collective pure dephasing noise combinations. In all cases, the bipartite entanglement…

Quantum Physics · Physics 2007-05-23 Kevin Ann , Gregg Jaeger