Rigorous Born approximation and beyond for the spin-boson model

DiVincenzo, D. P. and Loss, D.. (2005) Rigorous Born approximation and beyond for the spin-boson model. Physical Review B, Vol. 71, H. 3 , 035318, 10 S..

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Official URL: http://edoc.unibas.ch/dok/A5254670

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Within the lowest-order Born approximation, we present an exact calculation of the time dynamics of the spin-boson model in the Ohmic regime. We observe non-Markovian effects at zero temperature that scale with the system-bath coupling strength and cause qualitative changes in the evolution of coherence at intermediate times of order of the oscillation period. These changes could significantly affect the performance of these systems as qubits. In the biased case, we find a prompt loss of coherence at these intermediate times, whose decay rate is set by rootalpha, where alpha is the coupling strength to the environment. We also explore the calculation of the next-order Born approximation: we show that, at the expense of very large computational complexity, interesting physical quantities can be rigorously computed at fourth order using computer algebra, presented completely in an accompanying MATHEMATICA file. We compute the O(alpha) corrections to the long time behavior of the system density matrix; the result is identical to the reduced density matrix of the equilibrium state to the same order in alpha. All these calculations indicate precision experimental tests that could confirm or refute the validity of the spin-boson model in a variety of systems.
Faculties and Departments:05 Faculty of Science > Departement Physik > Physik > Theoretische Physik Mesoscopics (Loss)
UniBasel Contributors:Loss, Daniel
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:American Institute of Physics
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:22 Mar 2012 14:25
Deposited On:22 Mar 2012 13:48

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