scholarly journals Heat Generation by Electrical Current in a Quantum Dot Hybridized to Majorana Nanowires

2021 ◽  
Vol 9 ◽  
Author(s):  
Zhu-Hua Wang
Keyword(s):  
Quantum Dot ◽  
Bias Voltage ◽  
Heat Generation ◽  
Bound States ◽  
Waste Heat ◽  
Electrical Current ◽  
Function Technique ◽  
Heat Current ◽  
Low Dimensional ◽  
Direct Hybridization

Heat current generated by electronic transport through a quantum dot (QD) coupled to both a phonon bath and a Majorana nanowire hosting Majorana bound states (MBSs) is theoretically studied in the framework of non-equilibrium Green’s function technique. The calculated numerical results show that electrical current can be either enhanced or suppressed by the combined influences of the phonon bath and the MBSs at certain bias voltage regimes. The enhancement and suppression of the current’s magnitude for a fixed bias voltage will be reversed due to the direct hybridization between the MBSs. The simultaneous coupling between both MBSs will amplify the function of the MBSs on the current, with the same unchanged and essential qualitative impacts. Heat generation by the electrical current can be fully adjusted by the dot–MBS coupling, direct hybridization between the MBSs, and positions of the dot level. By properly choosing the above parameters, heat generation can be suppressed even for increased electrical current, which is favorable in removing waste heat generated by electrical current flowing through low-dimensional circuits.

scholarly journals Electronic Transport Through Double Quantum Dot Coupled to Majorana Bound States and Ferromagnetic Leads

2021 ◽  
Vol 8 ◽  
Author(s):  
Li-Wen Tang ◽  
Wei-Guo Mao
Keyword(s):  
Quantum Dot ◽  
Coupling Strength ◽  
Bound States ◽  
High Efficiency ◽  
Energy Levels ◽  
Electrical Current ◽  
Function Technique ◽  
Double Quantum ◽  
Majorana Bound States ◽  
Double Quantum Dot

We have studied theoretically the properties of electrical current and tunnel magnetoresistance (TMR) through a serially connected double quantum dot (DQD) sandwiched between two ferromagnetic leads by using the nonequilibrium Green’s function technique. We consider that each of the DQD couples to one mode of the Majorana bound states (MBSs) formed at the ends of a topological superconductor nanowire with spin-dependent coupling strength. By adjusting the sign of the spin polarization of dot–MBS coupling strength and the arrangement of magnetic moments of the two leads, the currents’ magnitude can be effectively enhanced or suppressed. Under some conditions, a negative TMR emerges which is useful in detection of the MBSs, a research subject currently under extensive investigations. Moreover, the amplitude of the TMR can be adjusted in a large regime by variation of several system parameters, such as direct hybridization strength between the MBSs or the dots and the positions of the dots’ energy levels. Such tunable currents and TMR may also find use in high-efficiency spintronic devices or information processes.

scholarly journals Dual Negative Differential of Heat Generation in a Strongly Correlated Quantum Dot Side-Coupled to Majorana Bound States

2021 ◽  
Vol 9 ◽  
Author(s):  
Zhu-Hua Wang ◽  
Wen-Cheng Huang
Keyword(s):  
Quantum Dot ◽  
Heat Generation ◽  
Coulomb Blockade ◽  
Bound States ◽  
Interaction Strength ◽  
Local Heat ◽  
Transport Processes ◽  
Strongly Correlated ◽  
Majorana Bound States ◽  
Coulomb Blockade Regime

We study theoretically the properties of local heat originated from energy exchange between electrons passing through a quantum dot (QD) coupled to a phonon bath. The dot is sandwiched between two normal metal leads and also side-coupled to Majorana bound states (MBSs) formed at opposite ends of a topological superconductor nanowire. We find that in addition to the negative differential of heat generation (NDHG) in the Coulomb blockade regime, another NDHG emerges near the leads’ Fermi level due to the dot-MBS coupling. This dual NDHG effect is robust against the variation of intradot Coulomb interaction strength, and disappears if the QD is coupled to regular Fermions. Direct hybridization between the MBSs reduces their impacts on the electronic transport processes, and eliminates the dual NDHG effect. Our results show that the dual NDHG effect is quite efficient for inferring the existence of MBSs, and may remedy some limitations of the detection schemes relying on tunneling spectroscopy technique.

Heat Generation by Electrical Current in Quantum Dot System with Fano Resonance

2012 ◽  
Vol 58 (2) ◽  
pp. 295-299 ◽  
Author(s):  
Qiao Chen ◽  
Mai-Chang Xu ◽  
Xi-Long Qu
Keyword(s):  
Quantum Dot ◽  
Heat Generation ◽  
Fano Resonance ◽  
Electrical Current

scholarly journals Topological isoconductance signatures in Majorana nanowires

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
L. S. Ricco ◽  
J. E. Sanches ◽  
Y. Marques ◽  
M. de Souza ◽  
M. S. Figueira ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Transport Properties ◽  
Spin Polarization ◽  
Bound States ◽  
Spin Asymmetry ◽  
Experimental Protocol ◽  
Zero Bias ◽  
Topological Superconductor ◽  
Hybrid Device ◽  
Majorana Bound States

AbstractWe consider transport properties of a hybrid device composed by a quantum dot placed between normal and superconducting reservoirs, and coupled to a Majorana nanowire: a topological superconducting segment hosting Majorana bound states (MBSs) at the opposite ends. It is demonstrated that if highly nonlocal and nonoverlapping MBSs are formed in the system, the zero-bias Andreev conductance through the dot exhibits characteristic isoconductance profiles with the shape depending on the spin asymmetry of the coupling between the dot and the topological superconductor. Otherwise, for overlapping MBSs with less degree of nonlocality, the conductance is insensitive to the spin polarization and the isoconductance signatures disappear. This allows to propose an alternative experimental protocol for probing the nonlocality of the MBSs in Majorana nanowires.

scholarly journals Quantum control of excitons for reversible heat transfer

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Conor N. Murphy ◽  
Paul R. Eastham
Keyword(s):  
Heat Transfer ◽  
Quantum Dot ◽  
Quantum Control ◽  
Heat Engine ◽  
Laser Pulses ◽  
Heat Current ◽  
Light Emitting ◽  
Laser Dressing ◽  
Working Medium ◽  
Heat Transfers

Abstract Lasers, photovoltaics, and thermoelectrically-pumped light emitting diodes are thermodynamic machines which use excitons (electron-hole pairs) as the working medium. The heat transfers in such devices are highly irreversible, leading to low efficiencies. Here we predict that reversible heat transfers between a quantum-dot exciton and its phonon environment can be induced by laser pulses. We calculate the heat transfer when a quantum-dot exciton is driven by a chirped laser pulse. The reversibility of this heat transfer is quantified by the efficiency of a heat engine in which it forms the hot stroke, which we predict to reach 95% of the Carnot limit. This performance is achieved by using the time-dependent laser-dressing of the exciton to control the heat current and exciton temperature. We conclude that reversible heat transfers can be achieved in excitonic thermal machines, allowing substantial improvements in their efficiency.

Transport through several four-quantum-dot topological structures

2021 ◽  
pp. 2150393
Author(s):  
Qingshuang Zhi ◽  
Kongfa Chen ◽  
Zelong He
Keyword(s):  
Quantum Dot ◽  
Coupling Strength ◽  
Bound States ◽  
Resonance Peak ◽  
Coulomb Interactions ◽  
Many Body ◽  
Body Effect ◽  
Topological Structures ◽  
Resonance Band ◽  
Interdot Coupling

In this paper, several four-quantum-dot topological structures are designed. The influence of the interdot coupling strength and intradot Coulomb interactions on the conductance is discussed. The location of the anti-resonance band can be manipulated by tuning the interdot coupling strength, which suggests a physical scheme of an effective quantum switch. The Fano anti-resonance peak may evolve into a resonance peak. For the particular value of the interdot coupling strength, two Fano anti-resonances collapse and bound states in the continuum are formed. Moreover, many-body effect makes the number of anti-resonance bands increase. This study provides a theoretical basis for the design of quantum computing devices.

Odd–Even Effect of the Persistent Current in a Quantum Dot Ring with Embedded Majorana Bound States

2015 ◽  
Vol 84 (2) ◽  
pp. 024707 ◽  
Author(s):  
Wei-Jiang Gong ◽  
Ying Zhao ◽  
Zhen Gao ◽  
Guangyu Yi ◽  
Xin Zhang
Keyword(s):  
Quantum Dot ◽  
Bound States ◽  
Persistent Current ◽  
Majorana Bound States

Bound states in a hybrid magnetic-electric quantum dot

2010 ◽  
Vol 108 (6) ◽  
pp. 064306 ◽  
Author(s):  
Yu Song ◽  
Yong Guo
Keyword(s):  
Quantum Dot ◽  
Bound States
Sign in / Sign up

Export Citation Format

Share Document