Nuclear-induced time evolution of entanglement of two-electron spins in anisotropically coupled quantum dot

Gehad Sadiek, Zhen Huang, Omar Aldossary, Sabre Kais

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

We study the time evolution of entanglement of two spins in an anisotropically coupled quantum dot interacting with the unpolarised nuclear spins environment. We assume that the exchange coupling strength in the z direction Jz is different from the lateral one Jl. We observe that the entanglement decays as a result of the coupling to the nuclear environment and reaches a saturation value, which depends on the value of the exchange interaction difference J = Jl - Jz between the two spins and the strength of the applied external magnetic field. We find that the entanglement exhibits a critical behaviour controlled by the competition between the exchange interaction J and the external magnetic field. The entanglement shows a quasi-symmetric behaviour above and below a critical value of the exchange interaction. It becomes more symmetric as the external magnetic field increases. The entanglement reaches a large saturation value, close to unity, when the exchange interaction is far above or below its critical value and a small one as it closely approaches the critical value. Furthermore, we find that the decay rate profile of entanglement is linear when the exchange interaction is much higher or lower than the critical value but converts to a power law and finally to a Gaussian as the critical value is approached from both directions. The dynamics of entanglement is found to be independent of the exchange interaction for an isotropically coupled quantum dot.

Original languageEnglish
Pages (from-to)1777-1786
Number of pages10
JournalMolecular Physics
Volume106
Issue number14
DOIs
Publication statusPublished - 1 Jul 2008
Externally publishedYes

Fingerprint

Quantum Dots
Exchange interactions
Magnetic Fields
electron spin
Semiconductor quantum dots
quantum dots
Electrons
interactions
Magnetic fields
magnetic fields
saturation
Exchange coupling
nuclear spin
decay rates
unity
Direction compound
decay
profiles

Keywords

  • Decoherence
  • Entanglement
  • Quantum computing

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Condensed Matter Physics
  • Biophysics
  • Molecular Biology

Cite this

Nuclear-induced time evolution of entanglement of two-electron spins in anisotropically coupled quantum dot. / Sadiek, Gehad; Huang, Zhen; Aldossary, Omar; Kais, Sabre.

In: Molecular Physics, Vol. 106, No. 14, 01.07.2008, p. 1777-1786.

Research output: Contribution to journalArticle

Sadiek, Gehad ; Huang, Zhen ; Aldossary, Omar ; Kais, Sabre. / Nuclear-induced time evolution of entanglement of two-electron spins in anisotropically coupled quantum dot. In: Molecular Physics. 2008 ; Vol. 106, No. 14. pp. 1777-1786.
@article{2802280376004352941e97503e01fa05,
title = "Nuclear-induced time evolution of entanglement of two-electron spins in anisotropically coupled quantum dot",
abstract = "We study the time evolution of entanglement of two spins in an anisotropically coupled quantum dot interacting with the unpolarised nuclear spins environment. We assume that the exchange coupling strength in the z direction Jz is different from the lateral one Jl. We observe that the entanglement decays as a result of the coupling to the nuclear environment and reaches a saturation value, which depends on the value of the exchange interaction difference J = Jl - Jz between the two spins and the strength of the applied external magnetic field. We find that the entanglement exhibits a critical behaviour controlled by the competition between the exchange interaction J and the external magnetic field. The entanglement shows a quasi-symmetric behaviour above and below a critical value of the exchange interaction. It becomes more symmetric as the external magnetic field increases. The entanglement reaches a large saturation value, close to unity, when the exchange interaction is far above or below its critical value and a small one as it closely approaches the critical value. Furthermore, we find that the decay rate profile of entanglement is linear when the exchange interaction is much higher or lower than the critical value but converts to a power law and finally to a Gaussian as the critical value is approached from both directions. The dynamics of entanglement is found to be independent of the exchange interaction for an isotropically coupled quantum dot.",
keywords = "Decoherence, Entanglement, Quantum computing",
author = "Gehad Sadiek and Zhen Huang and Omar Aldossary and Sabre Kais",
year = "2008",
month = "7",
day = "1",
doi = "10.1080/00268970802290313",
language = "English",
volume = "106",
pages = "1777--1786",
journal = "Molecular Physics",
issn = "0026-8976",
publisher = "Taylor and Francis Ltd.",
number = "14",

}

TY - JOUR

T1 - Nuclear-induced time evolution of entanglement of two-electron spins in anisotropically coupled quantum dot

AU - Sadiek, Gehad

AU - Huang, Zhen

AU - Aldossary, Omar

AU - Kais, Sabre

PY - 2008/7/1

Y1 - 2008/7/1

N2 - We study the time evolution of entanglement of two spins in an anisotropically coupled quantum dot interacting with the unpolarised nuclear spins environment. We assume that the exchange coupling strength in the z direction Jz is different from the lateral one Jl. We observe that the entanglement decays as a result of the coupling to the nuclear environment and reaches a saturation value, which depends on the value of the exchange interaction difference J = Jl - Jz between the two spins and the strength of the applied external magnetic field. We find that the entanglement exhibits a critical behaviour controlled by the competition between the exchange interaction J and the external magnetic field. The entanglement shows a quasi-symmetric behaviour above and below a critical value of the exchange interaction. It becomes more symmetric as the external magnetic field increases. The entanglement reaches a large saturation value, close to unity, when the exchange interaction is far above or below its critical value and a small one as it closely approaches the critical value. Furthermore, we find that the decay rate profile of entanglement is linear when the exchange interaction is much higher or lower than the critical value but converts to a power law and finally to a Gaussian as the critical value is approached from both directions. The dynamics of entanglement is found to be independent of the exchange interaction for an isotropically coupled quantum dot.

AB - We study the time evolution of entanglement of two spins in an anisotropically coupled quantum dot interacting with the unpolarised nuclear spins environment. We assume that the exchange coupling strength in the z direction Jz is different from the lateral one Jl. We observe that the entanglement decays as a result of the coupling to the nuclear environment and reaches a saturation value, which depends on the value of the exchange interaction difference J = Jl - Jz between the two spins and the strength of the applied external magnetic field. We find that the entanglement exhibits a critical behaviour controlled by the competition between the exchange interaction J and the external magnetic field. The entanglement shows a quasi-symmetric behaviour above and below a critical value of the exchange interaction. It becomes more symmetric as the external magnetic field increases. The entanglement reaches a large saturation value, close to unity, when the exchange interaction is far above or below its critical value and a small one as it closely approaches the critical value. Furthermore, we find that the decay rate profile of entanglement is linear when the exchange interaction is much higher or lower than the critical value but converts to a power law and finally to a Gaussian as the critical value is approached from both directions. The dynamics of entanglement is found to be independent of the exchange interaction for an isotropically coupled quantum dot.

KW - Decoherence

KW - Entanglement

KW - Quantum computing

UR - http://www.scopus.com/inward/record.url?scp=53449086631&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=53449086631&partnerID=8YFLogxK

U2 - 10.1080/00268970802290313

DO - 10.1080/00268970802290313

M3 - Article

AN - SCOPUS:53449086631

VL - 106

SP - 1777

EP - 1786

JO - Molecular Physics

JF - Molecular Physics

SN - 0026-8976

IS - 14

ER -