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Measuring the transmission of a quantum dot using Aharonov-Bohm Interferometers

Amnon Aharony·Ora Entin-Wohlman·Yoseph Imry
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Abstract

The conductance G through a closed Aharonov-Bohm mesoscopic solid-state interferometer (which conserves the electron current), with a quantum dot (QD) on one of the paths, depends only on cos(phi), where Phi= (hbar c phi)/e is the magnetic flux through the ring. The absence of a phase shift in the phi-dependence led to the conclusion that closed interferometers do not yield the phase of the "intrinsic" transmission amplitude t_D=|t_D|e^{i alpha} through the QD, and led to studies of open interferometers. Here we show that (a) for single channel leads, alpha can be deduced from |t_D|, with no need for interferometry; (b) the explicit dependence of G(phi) on cos(phi) (in the closed case) allows a determination of both |t_D| and alpha; (c) in the open case, results depend on the details of the opening, but optimization of these details can yield the two-slit conditions which relate the measured phase shift to alpha.

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Amnon Aharony, Ora Entin-Wohlman, Yoseph Imry. 2002-08-04. Measuring the transmission of a quantum dot using Aharonov-Bohm Interferometers. https://doi.org/10.1143/jpsjs.72sa.112

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