Quantum Kinetic Equations for Pre-thermal Light and Matter

Project Information

QUAKE4PRELIMAT

Grant agreement ID: 745608

DOI

10.3030/745608

Project terminated on 30 September 2019

EC signature date 1 March 2017

Start date 1 March 2018

End date 28 February 2021

Funded under

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Total cost

€ 265 840,20

EU contribution

€ 265 840,20

Coordinated by

UNIVERSITE DE GENEVE
Switzerland

Periodic Reporting for period 1 - QUAKE4PRELIMAT (Quantum Kinetic Equations for Pre-thermal Light and Matter)

Reporting period: 2018-03-01 to 2020-02-29

Summary of the context and overall objectives of the project

The project revolved around the idea of generating metastable states of quantum light interacting with atoms or molecules. This is of primary importance for using quantum many body systems out-of-equilibrium in realising novel technologies. For instance, by achieving quasi-steady states away from thermal equilibrium, one would possess a natural basis to engineer quantum computation and applications harnessing quantum coherence at a microscopic level.
Indeed, while systems that equilibrate falls into the conventional categorisation of classical thermodynamics, systems kept away from equilibration by a combination of drive, dissipation, and many-particle interactions would elude known principles of statistical mechanics, and open the door to novel and unprecedented quantum physical effects with applications in the near future.

During the project we achieved this goal already suggesting the onset of pre-thermal light coupled to quantum matter in two platforms: cavity QED systems involving spin one atoms coupled to photons, which are currently a state-of-art platform in the laboratories of Prof. Schleier-Smith in Stanford; and the prototypical model of an Ising chain with combined short and long range interactions mediated by a cavity photon, releasing metastable time crystals of light coupled to matter.

The project planted seeds of collaborations which are currently seeing novel ongoing work in this fascinating area.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

As anticipated in the previous section, the project has achieved two major goals related to the subject of the funding:

first, we have devised a protocol to engineer multi-photon states in cavity QED systems involving spin one atoms. The protocol relies on the possibility to organise the energy levels of the system into an elegant staircase which can be climbed with the aid of an external pump field, and allow for the generation of the desired hybrid state of light coupled to matter. Even more interestingly, when subject to photon losses, and properly pumped, this system could exhibit the metastability and prethermal features at the centre of the funding scheme of the project.

second, we have studied the formation of time crystals in light-matter coupled systems. Time crystals are exotic behaviour of spin dynamics, where the atoms oscillate at a period which is the double of the period of the externally imposed field. This is a self-organising principle of quantum matter out-of-equilibrium and quite remarkably we have discovered that even this novel phenomenon could exhibit pre-thermal phenomena when interactions and dissipation were properly tuned in an experimentally viable window of parameters.

The work consisted in applying many body methods and concepts (Landau-Zener transitions, time dependent spin wave theory, cumulants for many body dynamics) to problems mutated from quantum optics.

These results were disseminated in several invited seminars and colloquia in the USA and in the UE, as well as in international workshops.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

Currently, there are two ongoing projects resulting from the project, involving the Host of the outgoing phase: we are considering the formation of glassy phases in multi-mode cavity QED as an alternative route to generate non-thermal , metastable states in quantum many-body optics platforms; we are studying in the platform of Stanford the possibility to engineer light-matter interactions to generate dissipation channels with long-range spatial character, in order to create novel time-dependent correlation patterns

SInce the project deals with fundaments of quantum matter, we don;t expect any immediate potential socio-economic impact. We expect though that our theory results will foster and boost novel experiments in the field of quantum many body optics.

summary of the goals and of perspective directions