Connection between noise and quantum correlations in a double quantum dot

Abstract

We investigate the current and noise characteristics of a double quantum dot system. The strong correlations induced by the Coulomb interaction and the Pauli principle create entangled two-electron states and lead to signatures in the transport properties. We show that the interaction parameter , which measures the admixture of the double-occupancy contribution to the singlet state and thus the degree of entanglement, can be directly accessed through the Fano factor of super-Poissonian shot noise.

Fano stability diagram of a symmetric triple quantum dot

“…Finally, vertical steps in the Fano factor are clearly visible at the center of the threeand five-particle Coulomb diamonds. At these positions the energy levels of the states with one electron more or less than the participating Coulomb-or interference-blocked state are aligned, and a little change in the gate voltage favors one or the other side in transport, leading to a sudden change in the statistics that is unaffected by the bias voltage [34,35].…”

Quantum dot as spin current generator and energy harvester

“…the couplings between the central region and external leads, temperature differences and the voltage we calculate heat currents I R Q , I L Q and the charge current I c . The calculated currents fulfill, as they should, equation (27). We make use of these fluxes in calculations of the efficiency of the device which is defined by equation (26).…”

“…Such structures include inter alia planar systems [15][16][17][18][19][20] or systems containing single or double quantum dots. Theoretical studies of double quantum dots have been started very early with the main interests being focused on the Coulomb blockade effect [21][22][23][24][25][26], shot noise, tunnel magnetoresistance [27,28], etc. Later on, similar systems consisting of a single or double quantum dot have been extensively studied with the aim to find configurations with enhanced Seebeck coefficient S c or thermoelectric figure of merit Z c T [13,[29][30][31][32][33][34] or their spin counterparts i.e.…”

Enhanced shot noise in asymmetric interacting two-level systems

“…However, several theoretical works on various systems have showed that Coulomb interactions might also lead to a super-Poisson shot noise with a Fano factor F > 1. Examples of such systems are quantum dots that are coupled to ferromagnetic leads [7][8][9][10] , multi-levels quantum dots 11,12 , multidots structures [13][14][15][16][17][18] , and also three terminal quantum dots [19][20][21] . There are also experimental works [22][23][24][25][26] in which a super-Poisson noise was measured in quantum dots, rather than the sub-Poisson noise, which is expected from the single level model of the quantum dots.…”