The influence of side-coupled quantum dots on thermoelectric effect of parallel-coupled double quantum dot system

2018 ◽  
Vol 545 ◽  
pp. 377-382 ◽  
Author(s):  
Jiyuan Bai ◽  
Zelong He ◽  
Li Li ◽  
Suihu Dang ◽  
Yadong Li ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Double Quantum ◽  
Thermoelectric Effect ◽  
Coupled Quantum Dots ◽  
Double Quantum Dot

Impurities-contributed abnormal thermoelectric effect in a parallel double quantum dot structure

2014 ◽  
Vol 14 (1) ◽  
pp. 34-45 ◽  
Author(s):  
Wei-Jiang Gong ◽  
Hui-Min Wang ◽  
Yu Han ◽  
Si-Jing Zhang
Keyword(s):  
Quantum Dot ◽  
Double Quantum ◽  
Thermoelectric Effect ◽  
Double Quantum Dot

INTRINSIC AND EXTRINSIC DECOHERENCE FOR CHARGE QUBIT DYNAMICS IN A DOUBLE QUANTUM DOT

2014 ◽  
Vol 28 (02) ◽  
pp. 1450014
Author(s):  
LI WANG ◽  
TAO TU ◽  
GUO-PING GUO ◽  
GUANG-CAN GUO
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Double Quantum ◽  
Charge Qubit ◽  
Semiconductor Quantum Dot ◽  
Double Quantum Dot ◽  
Crucial Difference ◽  
A Charge ◽  
Environment Noise

In this paper, we investigate different decoherence sources with a charge qubit in a semiconductor quantum dot device. We distinguish between the intrinsic qubit population leakage and extrinsic environment noise, through a crucial difference in their signatures on the dynamics of the qubit. The results demonstrated here could help to develop unified understanding of decoherence mechanism in quantum dots and allow us to design suitable protocols for control and measurement.

Modulation of magnetotransport in asymmetrically coupled double quantum dot system

2016 ◽  
Vol 30 (22) ◽  
pp. 1650266 ◽  
Author(s):  
Yan-Hua Liao ◽  
Jin Huang ◽  
Wei-Zhong Wang
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Quantum Dots ◽  
Energy Level ◽  
Quantum Dot ◽  
Spin Polarization ◽  
Quantum Phase Transition ◽  
Double Quantum ◽  
Double Quantum Dot ◽  
Double Quantum Dots

We study the transport properties in double quantum dots asymmetrically coupled to leads in magnetic field. We focus on the situation in which the second dot (QD2) couples with the leads with a weak hybridization function. The results shows that by tuning the energy level [Formula: see text] of QD2 one can control the conductance and its spin polarization of the system. In the absence of magnetic field [Formula: see text], with increasing [Formula: see text], the conductance shows a dip structure. This behavior of conductance results from a continuous triplet–doublet quantum phase transition. In the presence of magnetic field [Formula: see text], we obtain a perfect spin filtering with a fully-polarized conductance of up-spin or down-spin.

scholarly journals Coherent transfer of quantum information in a silicon double quantum dot using resonant SWAP gates

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
A. J. Sigillito ◽  
M. J. Gullans ◽  
L. F. Edge ◽  
M. Borselli ◽  
J. R. Petta
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Double Quantum ◽  
High Fidelity ◽  
Silicon Quantum Dots ◽  
Field Gradients ◽  
Double Quantum Dot ◽  
Swap Gate ◽  
Magnetic Field Gradients ◽  
Qubit Operation

AbstractSpin-based quantum processors in silicon quantum dots offer high-fidelity single and two-qubit operation. Recently multi-qubit devices have been realized; however, many-qubit demonstrations remain elusive, partly due to the limited qubit-to-qubit connectivity. These problems can be overcome by using SWAP gates, which are challenging to implement in devices having large magnetic field gradients. Here we use a primitive SWAP gate to transfer spin eigenstates in 100 ns with a fidelity of $${\bar{F}}_{{\rm{SWAP}}}^{{\rm{(p)}}}=98 \%$$F¯SWAP(p)=98%. By swapping eigenstates we are able to demonstrate a technique for reading out and initializing the state of a double quantum dot without shuttling charges through the quantum dot. We then show that the SWAP gate can transfer arbitrary two-qubit product states in 300 ns with a fidelity of $${\bar{F}}_{{\rm{SWAP}}}^{{\rm{(c)}}}=84 \%$$F¯SWAP(c)=84%. This work sets the stage for many-qubit experiments in silicon quantum dots.

Thermoelectric Transport in a Double-Quantum-Dot Coupled to Majorana Zero Modes

2021 ◽  
Vol 16 (5) ◽  
pp. 753-761
Author(s):  
Jing Wang ◽  
Lian-Liang Sun ◽  
Feng Chi ◽  
Zhen-Guo Fu
Keyword(s):  
Quantum Dot ◽  
Function Technique ◽  
Double Quantum ◽  
Thermoelectric Effect ◽  
Thermoelectric Transport ◽  
Zero Modes ◽  
Symmetric Point ◽  
Double Quantum Dot ◽  
Sign Change ◽  
Non Equilibrium Green’S Function

Thermoelectric transport through a double-quantum-dot (DQD) connected to the left and right leads is theoretically investigated in the framework of non-equilibrium Green’s function technique. We consider that the dots are also coupled to Majorana zero modes (MZMs) prepared at the two ends of a topological superconductor nanowire. It is found that the sign change of thermopower, which is promising in the detection of MZMs, can be realized by tuning several system’s parameters related to the MZMs, such as the coupling strength between the dots and the MZMs, the direct coupling between the MZMs, or even the magnetic flux penetrating through the structure. The above parameters also lead to significant enhancement of the thermopower and thermoelectric figure of merit (FOM), which indicates the conversion efficiency between heat and electrical energies. We also find that in this DQD system, both the thermopower and FOM are simultaneously enhanced by the MZMs around the electron-hole symmetric point, an ideal phenomenon in applications of thermoelectric effect. In addition, the thermoelectric effect is remarkably enhanced by the direct hybridization between the MZMs, which is very different from the case in single-dot structure.

scholarly journals Large Voltage-Tunable Spin Valve Based on a Double Quantum Dot

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Patrycja Tulewicz ◽  
Kacper Wrześniewski ◽  
Szabolcs Csonka ◽  
Ireneusz Weymann
Keyword(s):  
Quantum Dot ◽  
Spin Valve ◽  
Double Quantum ◽  
Double Quantum Dot

Fano Effect in T-Shaped Double Quantum Dot Structure with Decoherence Effect

2008 ◽  
Vol 49 (3) ◽  
pp. 771-776 ◽  
Author(s):  
Gao Wen-Zhu ◽  
Gong Wei-Jiang ◽  
Zheng Yi-Song ◽  
Liu Yu ◽  
Lü Tian-Quan
Keyword(s):  
Quantum Dot ◽  
Double Quantum ◽  
Fano Effect ◽  
Double Quantum Dot ◽  
Decoherence Effect
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