# Driven-Dissipative Quantum Many-Body Systems

Abstract : My PhD was devoted to the study of driven-dissipative quantum many-body systems. These systems represent natural platforms to explore fundamental questions about matter under non-equilibrium conditions, having at the same time a potential impact on emerging quantum technologies. In this thesis, we discuss a spectral decomposition of single-particle Green functions of Markovian open systems, that we applied to a model of a quantum van der Pol oscillator. We point out that a sign property of spectral functions of equilibrium systems doesn't hold in the case of open systems, resulting in a surprising negative density of states", with direct physical consequences. We study the phase transition between a normal and a superfluid phase in a prototype system of driven-dissipative bosons on a lattice. This transition is characterized by a finite-frequency criticality corresponding to the spontaneous break of time-translational invariance, which has no analog in equilibrium systems. Later, we discuss the mean-field phase diagram of a Mott insulating phase stabilized by dissipation, which is potentially relevant for ongoing experiments. Our results suggest that there is a trade off between the fidelity of the stationary phase to a Mott insulator and robustness of such a phase at finite hopping. Finally, we present some developments towards using dynamical mean field theory (DMFT) for studying driven-dissipative lattice systems. We introduce DMFT in the context of driven-dissipative models and developed a method to solve the auxiliary problem of a single impurity, coupled simultaneously to a Markovian and a non-Markovian environment. As a test, we applied this novel method to a simple model of a fermionic, single-mode impurity.
Keywords :
Document type :
Theses
Domain :

Cited literature [269 references]

https://tel.archives-ouvertes.fr/tel-02420548
Contributor : Abes Star :  Contact
Submitted on : Friday, December 20, 2019 - 7:04:07 AM
Last modification on : Wednesday, September 23, 2020 - 4:35:33 AM
Long-term archiving on: : Saturday, March 21, 2020 - 1:58:16 PM

### File

81527_SCARLATELLA_2019_archiva...
Version validated by the jury (STAR)

### Identifiers

• HAL Id : tel-02420548, version 1

### Citation

Orazio Scarlatella. Driven-Dissipative Quantum Many-Body Systems. Quantum Physics [quant-ph]. Université Paris-Saclay, 2019. English. ⟨NNT : 2019SACLS281⟩. ⟨tel-02420548⟩

Record views