SEMINAR on Disorder and strong electron correlations: "Dephasing by non-Gaussian noise"

[CM ICTP - Trieste]

CONDENSED MATTER SECTION

	
SEMINAR on

Disorder and strong electron correlations





Thursday, 29 November   -    11:00 hrs.



Seminar Room,  Main Building - First floor






F. MARQUARDT
(LMU, Munich)




"Dephasing by non-Gaussian noise"


Abstract

The usual models for dissipative environments involve a bath of 
harmonic oscillators, producing Gaussian fluctuations. However, modern 
experiments on dephasing in qubits and electronic interferometers 
indicate strong coupling to non-Gaussian quantum noise. Most 
strikingly, the coherence (interference contrast) may oscillate as a 
function of time, voltage, and other control parameters. We present the 
theory behind a recent "controlled dephasing" experiment involving an 
electronic Mach-Zehnder interferometer strongly coupled to the 
non-Gaussian shot noise of a detector edge channel. Visibility 
oscillations are predicted (and experimentally found) for the coupling 
strength between system and bath exceeding a certain   threshold. We 
argue that this is a genuine and generic feature of non-Gaussian noise.