Conductance fluctuations in a quantum dot under almost periodic ac pumping
Abstract
It is shown that the variance of the linear dc-conductance fluctuations in an open quantum dot under a high-frequency ac pumping depends significantly on the spectral content of the ac field. For a sufficiently strong ac field γτφ<<1, where 1/τφ is the dephasing rate induced by ac noise and γ is the electron escape rate, the dc-conductance fluctuations are much stronger for the harmonic pumping than in the case of the noise ac field of the same intensity. The reduction factor r in a static magnetic field takes the universal value of 2 only for the white-noise pumping. For the strictly harmonic pumping A(t)=A0cos ωt of sufficiently large intensity the variance is almost insensitive to the static magnetic field r-1=2τφγ<<1. For the quasiperiodic ac field of the form A(t)=A0[cos(ω1t)+cos(ω2t)] with ω1,2>>γ and γτφ<<1 we predict effect of enchancement of conductance fluctuations at commensurate frequencies ω2/ω1=P/Q.
- Publication:
-
Physical Review B
- Pub Date:
- July 2001
- DOI:
- 10.1103/PhysRevB.64.033313
- arXiv:
- arXiv:cond-mat/0008193
- Bibcode:
- 2001PhRvB..64c3313W
- Keywords:
-
- 73.23.-b;
- 72.15.-v;
- 72.30.+q;
- Electronic transport in mesoscopic systems;
- Electronic conduction in metals and alloys;
- High-frequency effects;
- plasma effects;
- Condensed Matter - Mesoscale and Nanoscale Physics
- E-Print:
- 4 pages RevTex, 4 eps figures