Dephasing in the semiclassical limit is system-dependent

Abstract

We investigate dephasing in open quantum chaotic systems in the limit of large system size to Fermi wavelength ratio, $L/{\lambda }_F>>1$. We semiclassically calculate the weak localization correction $g^{wl}$ to the conductance for a quantum dot coupled to (i) an external closed dot and (ii) a dephasing voltage probe. In addition to the universal algebraic suppression $g^{wl}\propto (1+{\tau }_D/{\tau }_{\varphi }{)}^{-1}$ with the dwell time ${\tau }_D$ through the cavity and the dephasing rate ${\tau }_{\varphi }^{-1}$, we find an exponential suppression of weak localization by a factor $\propto \exp [-\tilde{\tau }/{\tau }_{\varphi }]$, with a system-dependent $\tilde{\tau }$. In the dephasing probe model, $\tilde{\tau }$ coincides with the Ehrenfest time, $\tilde{\tau }\propto \ln [L/{\lambda }_F]$, for both perfectly and partially transparent dot-lead couplings. In contrast, when dephasing occurs due to the coupling to an external dot, $\tilde{\tau }\propto \ln [L/\xi ]$ depends on the correlation length $\xi$ of the coupling potential instead of ${\lambda }_F$.

4 pages 3 figures (v2 contains numerous cosmetic changes)

References in corpus (5)

• Semiclassical Theory of Chaotic Conductors
• Ehrenfest time dependent suppression of weak localization
• Suppression of weak-localization (and enhancement of noise) by tunnelling in semiclassical chaotic transport
• Exponential sensitivity to dephasing of electrical conduction through a quantum dot
• Interplay of Ehrenfest time and dephasing time in ballistic conductors

Cited by in corpus (1)

• Decoherence, Entanglement and Irreversibility in Quantum Dynamical Systems with Few Degrees of Freedom