Strong system-bath coupling induces negative differential thermal conductance and heat amplification in nonequilibrium two-qubit systems.

  title={Strong system-bath coupling induces negative differential thermal conductance and heat amplification in nonequilibrium two-qubit systems.},
  author={Huan Liu and Chen Wang and Luqin Wang and Jie Ren},
  journal={Physical review. E},
  volume={99 3-1},
Quantum heat transfer is analyzed in nonequilibrium two-qubits systems by applying the nonequilibrium polaron-transformed Redfield equation combined with full counting statistics. Steady-state heat currents with weak and strong qubit-bath couplings are clearly unified. Within the two-terminal setup, the negative differential thermal conductance is unraveled with strong qubit-bath coupling and finite qubit splitting energy. The partially strong spin-boson interaction is sufficient to show the… 
Impact of counter-rotating-wave term on quantum heat transfer and phonon statistics in nonequilibrium qubit–phonon hybrid system*
Counter-rotating-wave terms (CRWTs) are traditionally viewed to be crucial in open small quantum systems with strong system-bath dissipation. Here by exemplifying in a nonequilibrium qubit-phonon
Photonic heat transport in three terminal superconducting circuit
We report an experimental realization of a three-terminal photonic heat transport device based on a superconducting quantum circuit. The central element of the device is a flux qubit made of a
Universal thermal transport and Brownian thermal transistors in mesoscopic systems
Fluctuations are strong in mesoscopic systems and of particular importance for the description of transport. Here, we show that they can be considered as one resource for the operations of open
Heat Transport in a Spin-Boson Model at Low Temperatures: A Multilayer Multiconfiguration Time-Dependent Hartree Study
In this work, quantum dynamic simulations are performed to study low temperature heat transport in a spin-boson model where a two-level subsystem is coupled to two independent harmonic baths.
Inelastic thermoelectric transport and fluctuations in mesoscopic system
In the past decade, a new research frontier emerges at the interface between physics and renewable energy, termed as the inelastic thermoelectric effects where inelastic transport processes play a key
Designing nonlinear thermal devices and metamaterials under the Fourier law: A route to nonlinear thermotics
Nonlinear heat transfer can be exploited to reveal novel transport phenomena and thus enhance people’s ability to manipulate heat flux at will. However, there hasn’t been a mature discipline called
Negative differential thermal resistance effect in a macroscopic homojunction
The negative differential thermal resistance (NDTR) effect is an important mechanism to realize a thermal transistor that is of great significance to realize thermal control. We find that with
Minimal quantum heat manager boosted by bath spectral filtering
We reveal the potentially important role of a general mechanism that has hitherto not been invoked in quantum heat management schemes, namely, spectral filtering of the coupling between the heat
Brownian thermal transistors and refrigerators in mesoscopic systems
Fluctuations are significant in mesoscopic systems and of particular importance in understanding quantum transport. Here, we show that fluctuations can be considered as a resource for the operations


Negative differential thermal conductance and heat amplification in a nonequilibrium triangle-coupled spin-boson system at strong coupling
We investigate the nonequilibrium quantum heat transfer in a triangle-coupled spin-boson system within a three-terminal setup. By including the nonequilibrium noninteracting blip approximation
Unifying quantum heat transfer in a nonequilibrium spin-boson model with full counting statistics
To study the full counting statistics of quantum heat transfer in a driven nonequilibrium spin-boson model, we develop a generalized nonequilibrium polaron-transformed Redfield equation with an
Quantum heat transport of a two-qubit system: Interplay between system-bath coherence and qubit-qubit coherence.
The HEOM results exhibit turnover behavior of the heat current as a function of the system-bath coupling strength for all values of the interqubit coupling strength, while the results obtained with the TCL and FGR approaches do not exhibit such behavior, because they do not possess the capability of treating the q-b and q-q coherences.
Quantum thermal transistor based on qubit-qutrit coupling.
It is shown that the thermal transistor, as a three-terminal device, allows a weak modulation heat current to switch on and off and effectively modulate the heat current between the other two terminals.
Quantum effects in thermal conduction: Nonequilibrium quantum discord and entanglement
We study the process of heat transfer through an entangled pair of two-level systems, demonstrating the role of quantum correlations in this nonequilibrium process. While quantum correlations
Dynamic control of quantum geometric heat flux in a nonequilibrium spin-boson model
We study the quantum geometric heat flux in the nonequilibrium spin-boson model. By adopting the noninteracting-blip approximation that is able to accommodate the strong system-bath coupling, we show
Energy transfer in the nonequilibrium spin-boson model: From weak to strong coupling.
A bias-induced nonmonotonic behavior of the energy conductance in the intermediate coupling regime, resulting from the resonant character of theEnergy transfer in the nonequilibrium spin-boson model, may offer a nontrivial quantum control knob over energy transfer at the nanoscale.
Quantum fluctuation theorem for heat exchange in the strong coupling regime
We study quantum heat exchange in a multistate impurity coupled to two thermal reservoirs. Allowing for strong system-bath interactions, we show that a steady-state heat-exchange fluctuation theorem
Frequency-dependent current noise in quantum heat transfer: A unified polaron calculation.
A theory which combines Markovian quantum master equations with a finite time full counting statistics is presented and it is found that the FDCN with varying coupling strengths or bias displays a universal Lorentzian-shape scaling form in the weak coupling regime, and a white noise spectrum emerges in the strong coupling regime due to distinctive spin dynamics.
Nonequilibrium Energy Transfer at Nanoscale: A Unified Theory from Weak to Strong Coupling
A fluctuation-decoupled quantum master equation approach is developed that is valid ranging from the weak to the strong system-bath coupling regime and dissects the energy transfer as multiple boson processes with even and odd parity.