Berlin 2008 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 31: Quantum dynamics, decoherence and quantum information

DY 31.9: Talk

Friday, February 29, 2008, 12:15–12:30, MA 004

Exact dynamics in the central spin model — •Michael Bortz¹, Christian Schneider², Joachim Stolze², and Robert Stübner² — ¹Fachbereich Physik, TU Kaiserslautern, Germany — ²Institut für Physik, TU Dortmund, Germany

We consider a single spin-1/2 which is coupled via inhomogeneous Heisenberg interactions to an arbitrary number of environment spins-1/2 (central spin model). The topic of this talk is the loss of polarization of the central spin due to its exchange with the bath spins. Since the central spin model is used widely to model the decoherence of an electron spin quantum bit interacting with nuclear spins in a quantum dot, this question also is of significant experimental interest.

Our focus here is on the investigation of exact solutions of the model, both for inhomogeneous couplings and in the homogeneous limit. Using these exact solutions, we discuss the effect of tuning free parameters of the model - i.e. the initial state, the inhomogeneity of the couplings, the number of bath spins and their magnetization - on the time evolution of the central spin.