Common Environmental Effects on Quantum Thermal Transistor

Gupt

2022

Entropy

We propose a minimal model of a Coulomb-coupled fermionic quantum dot thermal diode that can act as an efficient thermal switch and exhibit complete rectification behavior, even in the presence of a small temperature gradient. Using two well-defined dimensionless system parameters, universal characteristics of the optimal heat current conditions are identified. It is shown to be independent of any system parameter and is obtained only at the mean transitions point “−0.5”, associated with the equilibrium distribution of the two fermionic reservoirs, tacitly referred to as “universal magic mean”.

“…We implement the strong-coupling formalism following References [ 19 , 36 , 37 , 38 , 39 , 40 , 41 ] to arrive at the master equation describing the time evolution of the density matrix

of the coupled QDs system (See Appendix A )

.…”

Section: Model and Dynamicsmentioning

confidence: 99%

Universal Behavior of the Coulomb-Coupled Fermionic Thermal Diode

Gupt

2022

Entropy

“…The study of thermoelectric transport at the nanoscale is of significant importance for its potential applications in quantum technology and quantum engineering [1][2][3][4][5]. Much effort has been made to achieve high efficiency and coefficient of performance in thermoelectric nanodevices in both theory [6][7][8][9] and experiment [10,11], which mainly focus on the elastic transport processes [12][13][14][15][16][17]. Interestingly, Mahan and Sofo proposed the "best thermoelectrics" by using conductors with very narrow energy bands to reduce the thermal conductivity based on the Wiedemann-Franz law [18].…”

Section: Introductionmentioning

confidence: 99%

Multitask quantum thermal machines and cooperative effects

Lu¹,

Wang²,

Wang³

et al. 2022

Preprint

The performance of nonequilibrium work extraction in thermoelectric devices can be enhanced by introducing the phonon-assisted inelastic process. Herein, we study phonon-thermoelectric devices where particle current and phononic heat currents are coupled by dominating phonon-assisted inelastic process and fueled by chemical potential difference and temperature biases and show that inelastic thermoelectric setups have a much richer functionality diagram and can even simultaneously perform multiple tasks, such as heat engines, refrigerators, and heat pumps. From the viewpoint of entropy production, we study the efficiencies and coefficients of performance of multi-task quantum thermal machines by analyzing two typical thermoelectric devices and emphasize the role of the inelastic scattering process and multiple biases in multiterminal setups. In a three-terminal double-quantum-dot setup with a tunable gate, we show that it performs two useful tasks due to the phonon-assisted inelastic process dominating the transport. For four-terminal four-quantum-dot thermoelectric device, we demonstrate that additional thermodynamic affinity furnishes the system with both substantially enriched functionality diagrams and enhanced efficiency. The cooperation between the longitudinal and transverse thermoelectric effects in the three-terminal thermoelectric systems leads to markedly improved performance of the thermal machines. Our work provides insights into optimizing general thermoelectric devices.

“…During the last few years, several possible implementations of this device have been proposed considering tree–qubit systems [ 9 , 10 ], qubit–qutrit system [ 11 ], in circuits of superconducting qubits [ 12 ] and in a system with three-body interaction [ 14 ]. Eventually, also, networks of connected thermal transistors were proposed [ 15 , 16 ].…”

Section: Introductionmentioning

confidence: 99%

Quantum Thermal Amplifiers with Engineered Dissipation

Mandarino

2022

Entropy

A three-terminal device, able to control the heat currents flowing through it, is known as a quantum thermal transistor whenever it amplifies two output currents as a response to the external source acting on its third terminal. Several efforts have been proposed in the direction of addressing different engineering options of the configuration of the system. Here, we adhere to the scheme in which such a device is implemented as a three-qubit system that interacts with three separate thermal baths. However, another interesting direction is how to engineer the thermal reservoirs to magnify the current amplification. Here, we derive a quantum dynamical equation for the evolution of the system to study the role of distinct dissipative thermal noises. We compare the amplification gain in different configurations and analyze the role of the correlations in a system exhibiting the thermal transistor effect, via measures borrowed from the quantum information theory.