Dynamics of energy transport and entropy production in ac-driven quantum electron systems (original) (raw)
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A quantum dot driven by two ac gate potentials oscillating with a phase lag may be regarded as a quantum engine, where energy is transported and dissipated in the form of heat. In this chapter we introduce a microscopic model for a quantum pump and analyze the fundamental principle for the conservation of the charge and energy in this device. We also present the basics of two well established many-body techniques to treat quantum transport in harmonically time-dependent systems. We discuss the different operating modes of this quantum engine, including the mechanism of heat generation. Finally, we establish the principles of quantum refrigeration within the weak driving regime. We also show that it is possible to achieve a regime where part of the work done by some of the ac fields can be coherently transported and can be used by the other driving voltages.
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Entropy, 2016
The problem of time-dependent particle transport in quantum conductors is nowadays a well established topic. In contrast, the way in which energy and heat flow in mesoscopic systems subjected to dynamical drivings is a relatively new subject that cross-fertilize both fundamental developments of quantum thermodynamics and practical applications in nanoelectronics and quantum information. In this short review, we discuss from a thermodynamical perspective recent investigations on nonstationary heat and work generated in quantum systems, emphasizing open questions and unsolved issues.
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entropy Editorial: Quantum Transport in Mesoscopic Systems
2020
Mesoscopic physics has become a mature field. Its theoretical foundations and main models were established in the last two decades of the past century [1,2]. Ever since, quantum transport techniques have served as an excellent tool to understand the intriguing properties of charge carriers in nanoscale conductors [3,4]. However, in the last few years, the number of applications has grown so quickly that even experts find it difficult to stay updated with the recent advancements. The goal of the present special issue is to give a current snapshot of the field by means of a collection of review papers and research works that discuss the hottest theoretical questions and experimental results. While the average current was the focus of early studies, the interest has gradually shifted to time-resolved transport. The motivation is partly due to new devices, such as single-electron emitters, which are able to inject quantized current pulses onto a Fermi sea for the investigation of inelastic and interaction effects upon electronic collisions. This is the subject of the review paper by Filippone et al. [5], in which Fermi liquid theories are employed to analyze strong correlations (Coulomb interactions) in the out-of-equilibrium dynamics of mesoscopic capacitors, a type of mesoscopic system whose response is purely dynamical. Here, dynamics is enforced via a time-dependent potential applied to a nearby gate. Under certain circumstances, the interplay of this potential and Coulomb interactions can lead to fractionalization effects in a single-electron transfer (quantized pumping). Chen and Zhu [6] find quantum pumping for a double-barrier system in the adiabatic limit. The novelty lies in their consideration of Dirac-Weyl quasiparticles. Tokura [7] also consider slow potentials, but the system is now an interferometer that allows not only for Aharanov-Bohm phases but also for spin-dependent shifts, due to both Rashba and Dresselhaus spin-orbit couplings. Meanwhile, Hashimoto and Uchiyama [8] tackle the nonadiabatic regime and present a complete analysis of the pumped charge, spin, and energy induced by temperature modulations in the attached reservoirs. A particularly useful approach that deals with this kind of problems is based on generalized master rate equations. Moldoveanu, Manolescu, and Gumundsson [9] illustrate the power of this method for a hybrid quantum-dot system that hosts both electronic and bosonic degrees of freedom. Among other things, they solve the master equations, including many-body effects in the transient response to time-dependent signals applied at the contact regions. Dynamically driven quantum devices are also suitable systems for testing alternative theoretical formulations. An example is the work of Pandey et al. [10], in which the Bohmian quantum theory is utilized to elucidate the role of non-Markovian conditions in graphene probed at very high frequencies. In the recent cross-fertilization between thermodynamics and quantum physics, mesoscopic systems play a pivotal contribution. In their review article, Ansari, van Steensel, and Nazarov [11] connect information-theoretic concepts with the evaluation of entropy in quantum systems. They illustrate
2010
A quantum dot driven by two ac gate potentials oscillating with a phase lag may be regarded as a quantum engine, where energy is transported and dissipated in the form of heat. In this chapter we introduce a microscopic model for a quantum pump and analyze the fundamental principle for the conservation of the charge and energy in this device. We also present the basics of two well established many-body techniques to treat quantum transport in harmonically timedependent systems. We discuss the different operating modes of this quantum engine, including the mechanism of heat generation. Finally, we establish the principles of quantum refrigeration within the weak driving regime. We also show that it is possible to achieve a regime where part of the work done by some of the ac fields can be coherently transported and can be used by the other driving voltages.
Energy transport and heat production in
2009
A quantum dot driven by two ac gate potentials oscillating with a phase lag may be regarded as a quantum engine, where energy is transported and dissipated in the form of heat. In this chapter we introduce a microscopic model for a quantum pump and analyze the fundamental principle for the conservation of the charge and energy in this device. We also present the basics of two well established many-body techniques to treat quantum transport in harmonically timedependent systems. We discuss the different operating modes of this quantum engine, including the mechanism of heat generation. Finally, we establish the principles of quantum refrigeration within the weak driving regime. We also show that it is possible to achieve a regime where part of the work done by some of the ac fields can be coherently transported and can be used by the
Local temperatures and heat flow in quantum driven systems
Physical Review B, 2011
We discuss the concept of local temperature for quantum systems driven out of equilibrium by ac pumps showing explicitly that it is the correct indicator for heat flow. We also show that its use allows for a generalization of the Wiedemann-Franz law.
Thermal transport in out-of-equilibrium quantum harmonic chains
Physical Review E, 2015
We address the problem of heat transport in a chain of coupled quantum harmonic oscillators, exposed to the influences of local environments of various nature, stressing the effects that the specific nature of the environment has on the phenomenology of the transport process. We study in detail the behavior of thermodynamically relevant quantities such as heat currents and mean energies of the oscillators, establishing rigorous analytical conditions for the existence of a steady state, whose features we analyse carefully. In particular we assess the conditions that should be faced to recover trends reminiscent of the classical Fourier law of heat conduction and highlight how such a possibility depends on the environment linked to our system.