Singlet-triplet decoherence due to nuclear spins in a double quantum dot

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dc.creatorCoish, W. A.
dc.creatorLoss, Daniel
dc.date2005-06-03
dc.date.accessioned2026-07-07T06:18:17Z
dc.date.available2026-07-07T06:18:17Z
dc.descriptionWe have evaluated hyperfine-induced electron spin dynamics for two electrons confined to a double quantum dot. Our quantum solution accounts for decay of a singlet-triplet correlator even in the presence of a fully static nuclear spin system, with no ensemble averaging over initial conditions. In contrast to an earlier semiclassical calculation, which neglects the exchange interaction, we find that the singlet-triplet correlator shows a long-time saturation value that differs from 1/2, even in the presence of a strong magnetic field. Furthermore, we find that the form of the long-time decay undergoes a transition from a rapid Gaussian to a slow power law ($\sim 1/t^{3/2}$) when the exchange interaction becomes nonzero and the singlet-triplet correlator acquires a phase shift given by a universal (parameter independent) value of $3π/4$ at long times. The oscillation frequency and time-dependent phase shift of the singlet-triplet correlator can be used to perform a precision measurement of the exchange interaction and Overhauser field fluctuations in an experimentally accessible system. We also address the effect of orbital dephasing on singlet-triplet decoherence, and find that there is an optimal operating point where orbital dephasing becomes negligible.
dc.description12 pages, 4 figures
dc.identifierhttps://arxiv.org/abs/cond-mat/0506090
dc.identifierhttp://arxiv.org/abs/cond-mat/0506090
dc.identifierPhys. Rev. B 72, 125337 (2005)
dc.identifierdoi:10.1103/PhysRevB.72.125337
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/94683
dc.subjectMesoscale and Nanoscale Physics
dc.titleSinglet-triplet decoherence due to nuclear spins in a double quantum dot
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