We present a unified description of heat flow in two-terminal hybrid quantum systems. Using simple models, we analytically study nonlinear aspects of heat transfer between various reservoirs: metals, solids, and spin baths, mediated by the excitation/relaxation of a central (subsystem) mode. We demonstrate rich nonlinear current-temperature characteristics, originating from either the molecular anharmonicity, or the reservoirs (complex) energy spectra. In particular, we establish sufficient conditions for thermal rectification in two-terminal junctions. We identify two classes of rectifiers. In type-A rectifiers the density of states of the reservoirs are dissimilar. In type-B rectifiers the baths are identical, but include particles whose statistics differ from that of the subsystem, to which they asymmetrically couple. Nonlinear heat flow, and specifically thermal rectification, are thus ubiquitous effects that could be observed in a variety of systems, phononic, electronic, and photonic.
We investigate heat rectification in a two-qubit system coupled via the Dzyaloshinskii-Moriya (DM) interaction. We derive analytical expressions for heat currents and thermal rectification and provide possible physical mechanisms behind the observed results. We show that the anisotropy of DM interaction in itself is insufficient for heat rectification, and some other form of asymmetry is needed. We employ off-resonant qubits as the source of this asymmetry. We find the regime of parameters for higher rectification factors by examining the analytical expressions of rectification obtained from a…
Heat and noise control is essential for the continued development of quantum technologies. For this purpose, a particularly powerful tool is the heat rectifier, which allows for heat transport in one configuration of two baths but not the reverse. Here we propose a class of rectifiers that exploits the unidirectionality of a low temperature bath to force the system into a dark state thus blocking heat transport in one configuration of the two baths. However, if the two baths are switched around, a heat current is observed. An implementation using a qutrit coupled to two harmonic oscillators is…
We theoretically investigate a quantum heat diode based on two interacting flux qubits coupled to two heat baths. Rectification of heat currents is achieved by asymmetrically coupling the qubits to the reservoirs modelled as dissipative $RLC$ resonators. We find that the coherent interaction between the qubits can be exploited to enhance the rectification factor, which otherwise would be constrained by the baths temperatures and couplings. Remarkably high values of rectification ratio up to $\mathcal R \sim 3.5$ can be obtained for realistic system parameters, with an enhancement up to $\sim 2…
We show that for a quantum wire with a local asymmetric scattering potential the principal channels for charge and heat rectification decouple and renormalise differently under electron interactions, with heat rectification generally being more relevant. The polarisation of the rectification results from quantum interference and is tuneable through external gating. Furthermore, for spin polarised or helical electrons and sufficiently strong interactions a regime can be obtained in which heat transport is strongly rectified but charge rectification is very weak.
The control of thermal fluxes -- magnitude and direction, in mesoscale and nanoscale electronic circuits can be achieved by means of heat rectification using thermal diodes in two-terminal systems. The rectification coefficient $\mathcal{R}$, given by the ratio of forward and backward heat fluxes, varies with the design of the diode and the working conditions under which the system operates. A value of $\mathcal{R}\ll 1$ or $\mathcal{R}\gg 1$ is a signature of high heat rectification performance but current solutions allowing such ranges, necessitate rather complex designs. Here, we propose a …
We study heat rectification through quantum dots in the Coulomb blockade regime using a master equation approach. We consider both cases of two-terminal and four-terminal devices. In the two-terminal configuration, we analyze the case of a single quantum dot with either a doubly-degenerate level or two non-degenerate levels. In the sequential tunneling regime we analyze the behaviour of heat currents and rectification as functions of the position of the energy levels and of the temperature bias. In particular, we derive an upper bound for rectification in the closed-circuit setup with the doub…
Recent experiments at the nanoscales confirm that thermal rectifiers, the thermal equivalent of electrical diodes, can operate in the quantum regime. We present a thorough investigation of the effect of different particle exchange statistics, coherence, and collective interactions on the quantum heat transport of rectifiers with two-terminal junctions. Using a collision model approach to describe the open system dynamics, we obtain a general expression of the nonlinear heat flow that fundamentally deviates from the Landauer formula whenever quantum statistical or coherence asymmetries are pres…
Heat rectification through a quantum two-level system
Univ. Grenoble Alpes, CEA, Grenoble INP, IRIG, PHELIQS（格勒诺布尔阿尔卑斯大学、法国原子能和替代能源委员会、格勒诺布尔理工学院）；Institute for Solid State Physics, the University of Tokyo（东京大学固体物理研究所）
We derive the fundamental limit to near-field radiative thermal rectification mediated by an intrinsic semiconductor film within the framework of fluctuational electrodynamics. By leveraging the electromagnetic local density of states, we identify ε"_H/ε"_L as an upper bound on the rectification magnitude, where ε"_H and ε"_L are respectively the imaginary parts of the film permittivity at high and low temperatures. This bound is tight and can be approached regardless of whether the film is suspended or supported. For intrinsic silicon the limit can in principle exceed 10^9. Our work highlight…
Nonlinear devices, such as transistors, enable contemporary computing technologies. We theoretically investigate nonlinear effects, bearing a high fundamental scientific and technical relevance, in magnonics with emphasis on superconductor-ferromagnet hybrids. Accounting for finite magnon chemical potential, we theoretically demonstrate magnonic spin-Joule heating, the spin analogue of conventional electronic Joule heating. Besides suggesting a key contribution to magnonic heat transport in a broad range of devices, it provides insights into the thermal physics of non-conserved bosonic excitat…
We present a thermal device based on the near-field interaction between two substrates made of a polar and a metal-insulator-transition material. As a result of the temperature dependence of the optical properties, this device acts as a thermal rectifier, implying a strong asymmetry in the heat flux when reversing the two temperatures. By covering both substrates with a graphene sheet we show a significant enhancement of rectification coefficient. By investigating the flux spectral properties along with its distance dependence, we prove that this enhancement is associated to a change in the po…
Radiative thermal diodes based on two-element structures rectify heat flows thanks to a temperature dependence of material optical properties. The heat transport asymmetry through these systems, however, remains weak without a significant change in material properties with the temperature. Here we explore the heat transport in three-element radiative systems and demonstrate that a strong asymmetry in the thermal conductance can appear because of many-body interactions, without any dependence of optical properties on the temperature. The analysis of transport in three-body systems made with pol…
Radiative thermal rectification using superconducting materials
热整流现象是当两个相互作用的热库之间的温差反向时热通量不对称的表现。本文提出了一种基于高温超导材料的远场辐射热整流器，整流比可达$80%$。该值是文献中报告的最高值之一。研究了两种构型：超导体（Tl $_2$ Ba $_2$ CaCu $_2$ O $_8$）与1）黑体和2）另一种超导体（YBa $_2$ Cu $_3$ O $_7$）进行热交换。第一种配置显示出更高的最大整流比。此外，我们表明，这两个超导整流器表现出不同的整流制度取决于参考温度的选择，即恒温器的温度。所得结果对能量转换器件、高效低温辐射绝缘体工程和热逻辑电路的开发具有一定的参考价值。
Thermal rectification due to phonon confinement in nanoparticles
DLR Institute of Space Research（德国航空航天中心空间研究所）；PTB Berlin（德国联邦物理技术研究院柏林分院）；Physics Department “Aldo Pontremoli”, Università degli Studi di Milano（米兰大学阿尔多·蓬特雷莫利物理系）；Interdisciplinary Centre for Nanostructured Materials and Interfaces (CIMaINa)（纳米结构与界面跨学科中心）
Thermal rectification which is a diode-like behavior of heat flux has been studied over a long time. However, a universal and systematic physical description is still lacking. In this letter, a perturbation theory of thermal rectification is developed, which provides an analytical formula of the thermal rectification ratio. It reveals the linear relationship between the thermal rectification ratio and temperature difference. Furthermore, the size-dependence of the thermal rectification relies on the specific form of the thermal conductivity. In addition, several experimental and numerical obse…
We investigate the heat flow transport properties of a parallel-coupled double quantum-dot system connected to two reservoirs with a temperature bias in the Coulomb blockade regime. We demonstrate that the effects of thermal rectification and negative differential thermal conductance (NDTC) exist in this system and analyze the influences of energy level difference and Coulomb interaction on the thermal rectification and NDTC. We find that this system can achieve a high thermal rectification ratio and NDTC when the asymmetry factor of the system is enhanced.
Quantum mechanics dictates the band-structure of materials that is essential for functional electronic components. With increased miniaturization of devices, it becomes possible to exploit the full potential of quantum mechanics through the principles of superposition and entanglement. We propose a new class of quantum rectifiers that can leverage entanglement to dramatically increase performance by coupling two small spin chains through an effective double-slit interface. Simulations show that rectification is enhanced by several orders of magnitude even in small systems, and that the effect …
