Dresden 2003 – wissenschaftliches Programm

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SYQD: Quantum decoherence in solid state physics

SYQD 2: Quantum Decoherence in Solid State Physics II

SYQD 2.2: Vortrag

Dienstag, 25. März 2003, 17:45–18:00, HSZ/01

Spin-boson dynamics: A unified approach from weak to strong coupling — •M. Grifoni¹, M. Thorwart¹, and E. Paladino² — ¹Department of NanoScience, Technische Universiteit Delft, Niederlande — ²INFM e Università di Catania, Italien

We present a novel approximation scheme to describe in a unified way the dynamics of a two-level system coupled to an environment of harmonic oscillators. By taking higher order correlations into account, a theory for weakly interacting dipoles is formulated which is valid for a wide class of bath spectral densities. We obtain a generalized solution which bridges between the two well understood regimes of weak and strong damping. The result is discussed in the context of a superconducting flux qubit which is coupled to a read-out SQUID. Due to the peaked shape of the related bath spectral density, deviations from the predictions of the non-interacting blip approximation (NIBA) as well as from those of a weak-damping approach are found.