2004/07/20 by J. Tworzydlo, J. Tworzydło, A. Tajic +5 · 4 citations
Computer Science · Physics and Astronomy · #Cellular Automata and Applications #Quantum and electron transport phenomena #Quantum chaos and dynamical systems #cond-mat.mes-hall
paper · pdf · doi:10.1103/physrevlett.93.186806
published as Physical Review Letters 93, 186806 (2004) · 4 pages, 4 figures
arxiv created 2004/07/20 · openalex publication_date 2004/10/29 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
According to random-matrix theory, interference effects in the conductance of a ballistic chaotic quantum dot should vanish \ensuremath∝(\ensuremathτ_\ensuremathφ/\ensuremathτD)p when the dephasing time \ensuremathτ_\ensuremathφ becomes small compared to the mean dwell time \ensuremathτD. Aleiner and Larkin have predicted that the power law crosses over to an exponential suppression \ensuremath∝exp(\ensuremath-\ensuremathτE/\ensuremathτ_\ensuremathφ) when \ensuremathτ_\ensuremathφ drops below the Ehrenfest time \ensuremathτE. We report the first observation of this crossover in a computer simulation of universal conductance fluctuations. Their theory also predicts an exponential suppression \ensuremath∝exp(\ensuremath-\ensuremathτE/\ensuremathτD) in the absence of dephasing---which is not observed. We show that the effective random-matrix theory proposed previously for quantum dots without dephasing explains both observations.