# Thermal machines beyond the weak coupling regime

@article{Gallego2013ThermalMB, title={Thermal machines beyond the weak coupling regime}, author={Rodrigo Gallego and Arnau Riera and Jens Eisert}, journal={New Journal of Physics}, year={2013}, volume={16} }

How much work can be extracted from a heat bath using a thermal machine? The study of this question has a very long history in statistical physics in the weak-coupling limit, when applied to macroscopic systems. However, the assumption that thermal heat baths remain uncorrelated with associated physical systems is less reasonable on the nano-scale and in the quantum setting. In this work, we establish a framework of work extraction in the presence of quantum correlations. We show in a…

## 42 Citations

### Strongly Coupled Quantum Heat Machines.

- PhysicsThe journal of physical chemistry letters
- 2015

It is shown that strongly coupled QHMs may be as efficient as their weakly coupled counterparts, and a novel turnover behavior is found where their output saturates and disappears in the limit of ultrastrong coupling.

### Strong Coupling Corrections in Quantum Thermodynamics.

- PhysicsPhysical review letters
- 2018

This work provides strong-coupling corrections to the second law applicable to general systems in three of its different readings: As a statement of maximal extractable work, on heat dissipation, and bound to the Carnot efficiency.

### A quantum Otto engine with finite heat baths: energy, correlations, and degradation

- Physics
- 2017

We study a driven harmonic oscillator operating an Otto cycle by strongly interacting with two thermal baths of finite size. Using the tools of Gaussian quantum mechanics, we directly simulate the…

### Heat capacities of thermally manipulated mechanical oscillator at strong coupling

- PhysicsScientific Reports
- 2019

The phenomenological experimentally-oriented approach can stimulate development of new optomechanical and thermomechanicals experiments exploring basic concepts of strong coupling thermodynamics and parameter regimes corresponding to anomalous behavior of mechanical and thermodynamic characteristics.

### Experimental Characterization of a Spin Quantum Heat Engine.

- PhysicsPhysical review letters
- 2019

A quantum heat engine based on a spin-1/2 system and nuclear magnetic resonance techniques is experimentally implemented, able to reach an efficiency for work extraction very close to its thermodynamic limit.

### Work and entropy production in generalised Gibbs ensembles

- Physics
- 2015

Recent years have seen an enormously revived interest in the study of thermodynamic notions in the quantum regime. This applies both to the study of notions of work extraction in thermal machines in…

### Fundamental Limitations to Local Energy Extraction in Quantum Systems.

- PhysicsPhysical review letters
- 2019

This work fully characterize the distinct notion of "passivity" of a bipartite quantum system in the presence of strong coupling and entanglement by finding necessary and sufficient conditions for such extraction to be impossible, using techniques from semidefinite programing.

### Temperature as perturbation in quantum mechanics

- Physics
- 2021

The perturbative approach was adopted to develop a temperature-dependent version of nonrelativistic quantum mechanics in the limit of low-enough temperatures. A generalized, selfconsistent…

### Quantum thermodynamics of single particle systems

- PhysicsScientific Reports
- 2020

A theory of quantum thermodynamics that is applicable for arbitrary small systems, even for single particle systems coupled with a reservoir, and generalizes the concept of temperature beyond equilibrium that depends on the detailed dynamics of quantum states.

### Nonequilibrium thermodynamics in the strong coupling and non-Markovian regime based on a reaction coordinate mapping

- Physics
- 2016

We propose a method to study the thermodynamic behaviour of small systems beyond the weak coupling and Markovian approximation, which is different in spirit from conventional approaches. The idea is…

## References

SHOWING 1-10 OF 39 REFERENCES

### Fundamental limitations for quantum and nanoscale thermodynamics.

- PhysicsNature communications
- 2013

It is found that there are fundamental limitations on work extraction from non-equilibrium states, owing to finite size effects and quantum coherences, which implies that thermodynamical transitions are generically irreversible at this scale.

### Extraction of work from a single thermal bath in the quantum regime

- PhysicsPhysical review letters
- 2000

It is shown that then work can be extracted from the bath by cyclic variation of a parameter, and thermodynamic relations are shown to take a generalized Gibbsian form that may violate the Clausius inequality.

### Exact relaxation in a class of nonequilibrium quantum lattice systems.

- PhysicsPhysical review letters
- 2008

This work rigorously proves that the evolving state locally relaxes to a steady state with maximum entropy constrained by second moments--thus maximizing the entanglement.

### Thermalization and its mechanism for generic isolated quantum systems

- PhysicsNature
- 2008

It is demonstrated that a generic isolated quantum many-body system does relax to a state well described by the standard statistical-mechanical prescription, and it is shown that time evolution itself plays a merely auxiliary role in relaxation, and that thermalization instead happens at the level of individual eigenstates, as first proposed by Deutsch and Srednicki.

### Intensive temperature and quantum correlations for refined quantum measurements

- Physics
- 2011

We consider the concept of temperature in a setting beyond the standard thermodynamics prescriptions. Namely, rather than restricting to standard coarse-grained measurements, we consider observers…

### Work extraction and thermodynamics for individual quantum systems.

- PhysicsNature communications
- 2014

It is proved that the second law of thermodynamics holds in this framework, and a simple protocol is given to extract the optimal amount of work from the system, equal to its change in free energy.

### Quantum mechanical evolution towards thermal equilibrium.

- PhysicsPhysical review. E, Statistical, nonlinear, and soft matter physics
- 2009

It is proved, with virtually full generality, that reaching equilibrium is a universal property of quantum systems: almost any subsystem in interaction with a large enough bath will reach an equilibrium state and remain close to it for almost all times.

### Local temperature in quantum thermal states

- Physics
- 2009

We consider blocks of quantum spins in a chain at thermal equilibrium, focusing on their properties from a thermodynamical perspective. In a classical system the temperature behaves as an intensive…

### Locality of temperature

- Physics
- 2014

This work is concerned with thermal quantum states of Hamiltonians on spin and fermionic lattice systems with short range interactions. We provide results leading to a local definition of…

### Extracting work from quantum systems

- Physics
- 2013

We consider the task of extracting work from quantum systems in the resource theory perspective of thermodynamics, where free states are arbitrary thermal states, and allowed operations are energy…