Many-body quantum engines
Lead Research Organisation:
Queen's University Belfast
Department Name: Sch of Mathematics and Physics
Abstract
Thermodynamics, the science of energy transformation, of heat and work, has always played an important and special role in physics. Its formulation in the 19th century was triggered by practical questions of energy balance and efficiency during the industrial revolution. Since then, the laws of thermodynamics have survived every subsequent scientific revolution of the 20th century, including quantum theory and relativity. A surprising connection to information theory came with Maxwell's daemon, a being imagined to be capable of making hot particles move from a cold to a hot thermostat, thus contrary to the normal hot-to-cold heat flow. The information-physics connection was made stronger in the 20th century by the works of Szilard and Landauer, who designed engines powered by information, and Bennett who exorcised the Maxwell's daemon paradox.
As the physical dimension of engines get smaller and smaller, strong thermal fluctuations affect the amount of work produced and a new stochastic thermodynamics has been developed in response. Heat, work and entropy are not just functionals of a thermodynamic process anymore, but, because of random fluctuations, they become stochastic variables. The fundamental laws of thermodynamics are recovered when looking at average values.
Thanks to the tremendous advance in the experimental realisations of quantum technologies applications of thermodynamics with quantum devices are foreseeable in the near future. In the new emerging field of quantum thermodynamics a considerable effort is being devoted to the design and analysis of thermal machines and refrigerators operating at the quantum level and the theoretical foundation of thermodynamics from quantum principles, including the definition of thermodynamic quantities like heat and work, with inputs from quantum information theory.
There are currently several attempts at realising quantum machines, capable of producing work, with a few degrees of freedom, e.g. a single particle. Although quantum thermodynamics is developing very fast, it is not yet clear how to scale up such machines to systems composed of many quantum particles. This achievement would enable practical applications of quantum machines as autonomous devices capable of correcting errors and imperfections in quantum simulators and quantum computers as well as serving as assemblers of quantum materials at the nanoscale.
The overarching challenge of this project is to theoretically design thermal machines, that use as working substance an ensemble of many interacting quantum particles. More specifically, we will consider a network of interacting quantum particles, quantum harmonic oscillators and localised spins, externally driven and coupled to thermal and non-equilibrium reservoirs. The network will be arranged in order to transform heat into mechanical work, thus operating as a thermal engine, or to employ external work to extract heat from a cold reservoir for the realisation of a refrigerator. As a further step, we will optimise the geometry and architecture of the network itself to deliver work and refrigeration with the largest power and efficiency. Since it would be a formidable task to optimise all the tens of parameters of the Hamiltonian, we will employ machine learning techniques to this end. Finally, an important fraction of the project will be done in collaboration with two experimental groups working on ultracold atoms with the aim of designing thermal machines that can be realised with their current experimental setups. In collaboration with the J. Sherson (Aarhus) we will design an engine whose working substance and reservoirs are realised with ultracold atoms in optical lattice potentials. In collaboration with T. Donner (Zürich) we will design a refrigerator made of two atomic Bose-Einstein condensates that interact with the common mode of an optical cavity.
As the physical dimension of engines get smaller and smaller, strong thermal fluctuations affect the amount of work produced and a new stochastic thermodynamics has been developed in response. Heat, work and entropy are not just functionals of a thermodynamic process anymore, but, because of random fluctuations, they become stochastic variables. The fundamental laws of thermodynamics are recovered when looking at average values.
Thanks to the tremendous advance in the experimental realisations of quantum technologies applications of thermodynamics with quantum devices are foreseeable in the near future. In the new emerging field of quantum thermodynamics a considerable effort is being devoted to the design and analysis of thermal machines and refrigerators operating at the quantum level and the theoretical foundation of thermodynamics from quantum principles, including the definition of thermodynamic quantities like heat and work, with inputs from quantum information theory.
There are currently several attempts at realising quantum machines, capable of producing work, with a few degrees of freedom, e.g. a single particle. Although quantum thermodynamics is developing very fast, it is not yet clear how to scale up such machines to systems composed of many quantum particles. This achievement would enable practical applications of quantum machines as autonomous devices capable of correcting errors and imperfections in quantum simulators and quantum computers as well as serving as assemblers of quantum materials at the nanoscale.
The overarching challenge of this project is to theoretically design thermal machines, that use as working substance an ensemble of many interacting quantum particles. More specifically, we will consider a network of interacting quantum particles, quantum harmonic oscillators and localised spins, externally driven and coupled to thermal and non-equilibrium reservoirs. The network will be arranged in order to transform heat into mechanical work, thus operating as a thermal engine, or to employ external work to extract heat from a cold reservoir for the realisation of a refrigerator. As a further step, we will optimise the geometry and architecture of the network itself to deliver work and refrigeration with the largest power and efficiency. Since it would be a formidable task to optimise all the tens of parameters of the Hamiltonian, we will employ machine learning techniques to this end. Finally, an important fraction of the project will be done in collaboration with two experimental groups working on ultracold atoms with the aim of designing thermal machines that can be realised with their current experimental setups. In collaboration with the J. Sherson (Aarhus) we will design an engine whose working substance and reservoirs are realised with ultracold atoms in optical lattice potentials. In collaboration with T. Donner (Zürich) we will design a refrigerator made of two atomic Bose-Einstein condensates that interact with the common mode of an optical cavity.
Planned Impact
The aim of this project is to develop thermodynamic applications at the microscopic quantum level with many interacting particles. Given the variegate and interdisciplinary character of this research, I anticipate a profound impact in different areas of physics and related disciplines as explained in the academic beneficiaries. This will be achieved with the aid of our plan for dissemination discussed in the document "Pathways to impact". Moreover, the organisation of a workshop on quantum thermodynamics will continue and enhance networking activities that are much needed in this emerging area. This will benefit scientists working on quantum thermodynamics from a statistical mechanics perspective as well as a more quantum information oriented approach.
Knowledge transfer will be also achieved with the distribution of our software through a Creative Commons licence.
This project will also provide cutting edge training for the PDRA who will learn and develop advanced algorithms for treating many-body quantum systems our of equilibrium. These methods could be transferred to different problems in other areas, for example transport problems in mesoscopic physics, quantum chemistry but also simulation of non equilibrium dynamics in classical stochastic processes. The PDRA will develop fundamental skills such as writing for different audiences (grant and fellowship proposals, scientific papers, popular press), communicating orally (through delivery of seminars, talks and lectures), information technology literacy (through design and management of websites, blogs, pages in social media) that can be also spent outside academia. Part of this training will be provided "in-house" by the Quantum Technology group, by Queen's University Belfast through formal training and by specific training provided elsewhere (as in the case of the Royal Society training for Communication and Media Skills).
In the long term, in the development of commercially affordable quantum technologies, the management of energy dissipation will be of crucial importance. Investigating means of disposing of this energy using specifically constructed quantum refrigerators directly embedded in the quantum device can be a viable solution. Our research represents a first step along this direction supporting the quantum industry in UK and worldwide.
Finally, we plan to disseminate through dedicated outreach activities the implications of our investigations in the quantum microscopic foundation of thermodynamics.
Knowledge transfer will be also achieved with the distribution of our software through a Creative Commons licence.
This project will also provide cutting edge training for the PDRA who will learn and develop advanced algorithms for treating many-body quantum systems our of equilibrium. These methods could be transferred to different problems in other areas, for example transport problems in mesoscopic physics, quantum chemistry but also simulation of non equilibrium dynamics in classical stochastic processes. The PDRA will develop fundamental skills such as writing for different audiences (grant and fellowship proposals, scientific papers, popular press), communicating orally (through delivery of seminars, talks and lectures), information technology literacy (through design and management of websites, blogs, pages in social media) that can be also spent outside academia. Part of this training will be provided "in-house" by the Quantum Technology group, by Queen's University Belfast through formal training and by specific training provided elsewhere (as in the case of the Royal Society training for Communication and Media Skills).
In the long term, in the development of commercially affordable quantum technologies, the management of energy dissipation will be of crucial importance. Investigating means of disposing of this energy using specifically constructed quantum refrigerators directly embedded in the quantum device can be a viable solution. Our research represents a first step along this direction supporting the quantum industry in UK and worldwide.
Finally, we plan to disseminate through dedicated outreach activities the implications of our investigations in the quantum microscopic foundation of thermodynamics.
People |
ORCID iD |
Gabriele De Chiara (Principal Investigator) |
Publications
Abah O
(2019)
Energetic cost of quantum control protocols
in New Journal of Physics
Abah O
(2022)
Harnessing nonadiabatic excitations promoted by a quantum critical point: Quantum battery and spin squeezing
in Physical Review Research
Carollo F
(2024)
Quantum thermodynamics of boundary time-crystals
in Quantum Science and Technology
Cattaneo M
(2021)
Collision Models Can Efficiently Simulate Any Multipartite Markovian Quantum Dynamics.
in Physical review letters
Coopmans L
(2022)
Optimal control in disordered quantum systems
in Physical Review Research
Coopmans L
(2022)
Optimal Control in Disordered Quantum Systems
Cusumano S
(2024)
Structured quantum collision models: generating coherence with thermal resources
in New Journal of Physics
De Chiara G
(2020)
Quantum machines powered by correlated baths
De Chiara G
(2020)
Quantum machines powered by correlated baths
in Physical Review Research
De Chiara G
(2022)
Quantum fluctuation theorem for dissipative processes
in Physical Review Research
Garbe L
(2022)
Critical quantum metrology with fully-connected models: from Heisenberg to Kibble-Zurek scaling
in Quantum Science and Technology
Garbe L
(2022)
Exponential time-scaling of estimation precision by reaching a quantum critical point
in Physical Review Research
Hammam K
(2022)
Exploiting coherence for quantum thermodynamic advantage
in New Journal of Physics
Hammam K
(2022)
Exploiting coherence for quantum thermodynamic advantage
Hammam K
(2024)
Quantum coherence enables hybrid multitask and multisource regimes in autonomous thermal machines
in Physical Review Research
Hewgill A
(2021)
Quantum thermodynamically consistent local master equations
in Physical Review Research
Hewgill A
(2020)
Three-qubit refrigerator with two-body interactions.
in Physical review. E
Hewgill A
(2020)
Quantum thermodynamically consistent local master equations
Hewgill A
(2019)
Three-qubit refrigerator with two-body interactions
Imparato A
(2024)
A thermodynamic approach to optimization in complex quantum systems
in Quantum Science and Technology
Innocenti L
(2020)
Ultrafast critical ground state preparation via bang-bang protocols
in New Journal of Physics
Leitch H
(2024)
Thermodynamics of hybrid quantum rotor devices
in Physical Review E
Leitch H
(2022)
Driven quantum harmonic oscillators: A working medium for thermal machines
in AVS Quantum Science
Myers N
(2021)
Quantum Otto engines at relativistic energies
Myers N
(2021)
Quantum Otto engines at relativistic energies
in New Journal of Physics
Myers N
(2022)
Boosting engine performance with Bose-Einstein condensation
in New Journal of Physics
Myers N
(2021)
Boosting engine performance with Bose-Einstein condensation
Myers N
(2022)
Quantum thermodynamic devices: From theoretical proposals to experimental reality
in AVS Quantum Science
Nosrati F
(2024)
Indistinguishability-assisted two-qubit entanglement distillation
in Quantum Science and Technology
Nosrati F
(2023)
Indistinguishability-assisted two-qubit entanglement distillation
Paternostro M
(2019)
Out of equilibrium thermodynamics of quantum harmonic chains
in Journal of Statistical Mechanics: Theory and Experiment
Peña FJ
(2020)
Quasistatic and quantum-adiabatic Otto engine for a two-dimensional material: The case of a graphene quantum dot.
in Physical review. E
Piccione N
(2020)
Power maximization of two-stroke quantum thermal machines
Piccione N
(2021)
Power maximization of two-stroke quantum thermal machines
in Physical Review A
Rodrigues FLS
(2019)
Thermodynamics of Weakly Coherent Collisional Models.
in Physical review letters
Singh V
(2022)
Unified trade-off optimization of quantum harmonic Otto engine and refrigerator.
in Physical review. E
Description | We investigated the thermodynamics of open quantum systems finding several results. Local master equations are a widespread tool to model open quantum systems, especially in the context of many-body systems. These equations, however, are believed to lead to thermodynamic anomalies and violation of the laws of thermodynamics. In contrast, here we rigorously prove that local master equations are consistent with thermodynamics and its laws without resorting to a microscopic model, as done in previous works. In particular, we consider a quantum system in contact with multiple baths and identify the relevant contributions to the total energy, heat currents, and entropy production rate. We show that the second law of thermodynamics holds when one considers the proper expression we derive for the heat currents. We confirm the results for the quantum heat currents by using a heuristic argument that connects the quantum probability currents with the energy currents, using an analogous approach as in classical stochastic thermodynamics. We finally use our results to investigate the thermodynamic properties of a set of quantum rotors operating as thermal devices and show that a suitable design of three rotors can work as an absorption refrigerator or a thermal rectifier. For the machines considered here, we also perform an optimization of the system parameters using an algorithm of reinforcement learning. We also investigated the thermodynamics of systems of quantum harmonic oscillators and qubits subject to coherent baths. In a more recent study, we explored the impact of non-equilibrium effects, specifically quantum coherence, on the performance of thermal devices engaged in thermodynamic tasks, demonstrating that even small amounts of coherence in thermal reservoirs can lead to combined and hybrid modes of operation, allowing the simultaneous performance of multiple thermodynamic tasks with varying implications for efficiency and performance. |
Exploitation Route | They can be useful for confirming predictions of the theory of quantum thermodynamics in experimental realisations. In fact, some of our designs have been and will be used in experimental demonstrations of collision models, for instance on superconducting quantum computers. |
Sectors | Electronics Energy Environment |