Noise spectrum of quantum transport through double quantum dots: Renormalization and non-Markovian effects

Abstract

Based on the time-nonlocal particle number-resolved master equation, we investigate the sequential electron transport through the interacting double quantum dots. Our calculations show that there exists the effect of energy renormalization in the dispersion of the bath interaction spectrum and it is sensitive to the the bandwidth of the bath. This effect would strongly affect the stationary current and its zero-frequency shot noise for weak inter-dot coherent coupling strength, but for strong inter-dot coupling regime, it is negligible due to the strong intrinsic Rabi coherent dynamics. Moreover, the possible observable effects of the energy renormalization in the noise spectrum are also investigated through the Rabi coherence signal. Finally, the non-Markovian effect is manifested in the finite-frequency noise spectrum with the appearance of quasisteps, and the magnitude of these quasisteps are modified by the dispersion function.

Transient Charge and Energy Flow in the Wide-Band Limit

“…The WBL assumes that the detailed structure of the density of states in the leads is not important for the description of transport, which substantially simplifies computations. The WBL for charge transport is justified when the bandwidth is large compared to the applied bias [21][22][23][24][25][26][27] .…”

“…The WBL assumes that the detailed structure of the density of states in the leads is not important for the description of transport, which substantially simplifies computations. The WBL for charge transport is justified when the bandwidth is large compared to the applied bias. − An important requirement for the WBL is that it should not induce any spurious, unphysical dynamics. Its only purpose is to allow for an efficient description of dynamics in large scale open quantum systems.…”

Memory effect preserved time-local approach to noise spectrum of transport current

“…The corresponding Rabi frequency denoted by ∆ is the energy difference between the two eigenstates (ε ± ), e.g., ∆ = ε + − ε − = 2Ω for the degenerate DQDs (ε l = ε r = ε 0 ) considered here. The characteristic of the Rabi coherence has been well studied in the symmetrized noise spectrum [36][37][38][39]. Now we apply the present TL-EOM approach to calculate the quantum noise spectrums of the transport current through DQDs.…”

Nonadiabatic Electron Dynamics in Tunneling Junctions: Lattice Exchange-Correlation Potential

“…In principle, Γ α is energy dependent, however, here we take the wide-band limit approximation. This disregards the energy dependence of the leads’ density of states, taking it constant and equal to its value at the Fermi energy. − This is justified when the applied bias is small compared to the leads’ bandwidth. One major advantage of taking the wide-band limit is that it allows for an analytical evaluation of the LB formula at finite temperatures. − …”