Quantum regression in dephasing phenomena

Spin dephasing in quantum wires

We study high-field spin transport in a quantum wire using a semiclassical approach. Spin dephasing (or spin depolarization) in the wire is caused by D’yakonov-Perel’ relaxation associated with bulk inversion asymmetry (Dresselhaus spin-orbit coupling) and structural inversion asymmetry (Rashba spin-orbit coupling). The depolarization rate is found to depend strongly on the initial polarization...

Dephasing in Open Quantum Dots

Shape-averaged magnetoconductance (weak localization) is used for the first time to obtain the electron phase coherence time tf in open ballistic GaAs quantum dots. Values for tf in the range of temperature T from 0.34 to 4 K are found to be independent of dot area, and are not consistent with the tf ~ T22 behavior expected for isolated dots. Surprisingly, tfsT d agrees quantitatively with the ...

Quantum dephasing by chaos

We examine whether the chaotic behavior of classical systems with a limited number of degrees of freedom can produce quantum dephasing, against the conventional idea that dephasing takes place only in large systems with a huge number of constituents and complicated internal interactions. On the basis of this analysis, we briefly discuss the possibility of defining quantum chaos and of inventing...

Dephasing in InAs/GaAs quantum dots

Ultralong dephasing time in InGaAs quantum dots.

We measure a dephasing time of several hundred picoseconds at low temperature in the ground-state transition of strongly confined InGaAs quantum dots, using a highly sensitive four-wave mixing technique. Between 7 and 100 K the polarization decay has two distinct components resulting in a non-Lorentzian line shape with a lifetime-limited zero-phonon line and a broadband from elastic exciton-aco...