A5069682831- Strong Light-Matter Interactions
- Cold Atom Physics and Bose-Einstein Condensates
- Physics of Superconductivity and Magnetism
- Quantum and electron transport phenomena
- Spectroscopy and Quantum Chemical Studies
- Quantum, superfluid, helium dynamics
- Photonic and Optical Devices
- Thermal Radiation and Cooling Technologies
- Topological Materials and Phenomena
- Advanced Fiber Laser Technologies
- Electronic and Structural Properties of Oxides
- Mechanical and Optical Resonators
- Nonlinear Photonic Systems
- Random lasers and scattering media
- Quantum Electrodynamics and Casimir Effect
- Quantum Information and Cryptography
- Quantum Mechanics and Non-Hermitian Physics
- Semiconductor Quantum Structures and Devices
- Advanced Thermodynamics and Statistical Mechanics
- Quantum optics and atomic interactions
- Quantum many-body systems
- Atomic and Subatomic Physics Research
- Organic and Molecular Conductors Research
- Magnetic and transport properties of perovskites and related materials
- Photoreceptor and optogenetics research
Université Libre de Bruxelles
2023-2025
University of Trento
2018-2024
ETH Zurich
2021-2024
University of Milan
2016-2018
We address characterization of many-body superradiant systems and establish a fundamental connection between quantum criticality the possibility locally estimating coupling constant, i.e., extracting its value by probing only portion whole system. In particular, we consider Dicke-like made an ensemble two-level atoms interacting with single-mode radiation field at zero effective temperature, estimation measurements performed on radiation. At first, obtain analytically Fisher information...
Exciton-polaritons in semiconductor microcavities constitute the archetypal realization of a quantum fluid light. Under coherent optical drive, remarkable effects such as superfluidity, dark solitons or nucleation hydrodynamic vortices have been observed. These phenomena can be all understood specific manifestation collective excitations forming on top polariton condensate. In this work, we performed Brillouin scattering experiment to measure their dispersion relation $\omega(\mathbf{k})$...
We present a theoretical study of the temporal and spatial coherence properties topological laser device built by including saturable gain on edge sites Harper-Hofstadter lattice for photons. For small enough lattices, Bogoliubov analysis applies, time is almost determined total number photons in agreement with standard Schawlow-Townes phase diffusion. In larger looking at lasing mode comoving frame its chiral motion, spatiotemporal correlations long-wavelength fluctuations display...
Recent advances in fabrication of two dimensional materials and their moir\'e heterostructures have opened up new avenues for realization ground-state excitonic insulators, where the structure spontaneously develops a finite interlayer electronic polarization. We propose analyze scheme an optically generated intralayer exciton is screened by excitations out insulator to form polarons. Using Quantum Monte-Carlo calculations we first determine binding energy biexciton state composed inter-...
Immersing a mobile impurity into many-body quantum system represents theoretically intriguing and experimentally effective way of probing its properties. In this work, we study the polaron spectral function in various environments, within framework Fermi-Hubbard models. Inspired by possible realizations cold atoms semiconductor heterostructures, consider different configurations for background Fermi gas, including charge density waves, multiple seas pair superfluids. While our calculations...
We study quantum effects of the vacuum light-matter interaction in materials embedded optical cavities. focus on electronic response a two-dimensional semiconductor placed inside planar cavity. By using diagrammatic expansion electron-photon interaction, we describe signatures hybridization characterized by large asymmetric shifts spectral weight at resonant frequencies. follow evolution light dressing from cavity to free-space limit. In limit, results modification gap with sizable appearing...
Multidimensional spectroscopy is becoming an increasingly popular tool and there ongoing effort to access electronic transitions many-body dynamics in correlated materials. We apply the protocol recently proposed by Wang [Phys. Rev. A 107, 013305 (2023)] extract two-dimensional polaron spectra a Fermi superfluid with impurity. The bath described BCS ansatz it assumed that impurity can scatter at most one quasiparticle pair. spectral response contains symmetric contribution, which carries...
We investigate the finite-size origin of coherence time (or equivalently its inverse, emission linewidth) a spatially extended, one-dimensional nonequilibrium condensate. show that well-known Schawlow-Townes scaling laser theory, possibly including Henry broadening factor, only holds for small system sizes, while in larger systems linewidth displays novel determined by Kardar-Parisi-Zhang physics. This is shown to lead an opposite dependence on optical nonlinearity two cases. then study how...
In this paper we discuss, within the Gross--Pitaevskii framework, superfluidity, soliton nucleation, and instabilities in a non-equilibrium polariton fluid injected by spatially localized continuous-wave coherent pump flowing against defect located outside spot. contrast to equilibrium condensates, steady-state solutions of driven-dissipative equations specific geometry hardly show clean superfluid flow around rather feature crossover from shallow deep soliton-like perturbation. This is...
We show that lasing in flat-band lattices can be stabilized by means of the geometrical properties Bloch states, settings where single-particle dispersion is flat both its real and imaginary parts. illustrate a general projection method compute collective excitations, which display diffusive behavior ruled quantum geometry through peculiar coefficient involving gain, losses interactions, entailing resilience against modulational instabilities. Then, we derive an equation motion for phase...
We theoretically demonstrate that the hallmarks of correlation and fermionization in a one-dimensional exciton-polariton gas can be observed with state-of-the-art technology. Our system consists chain excitonic quantum dots coupled to photonic waveguide, low filling polaritons. analytically identify Tonks-Girardeau, Tavis-Cummings, mean-field limits relate them different regimes anharmonicity bandwidth. Using matrix-product states, we numerically calculate ground-state energies, functions,...
Theory of superfluid $^4$He shows that, due to strong correlations and backflow effects, the density profile a vortex line has character modulation it is not simple rarefaction region as found in clouds cold bosonic atoms. We find that basic features this are represented by wave--packet cylindrical symmetry which rotons with positive group velocity have dominant role: The can be viewed cloud virtual excitations, mainly rotons, sustained phase wave function. This suggests reconnection some...
We theoretically study the collective excitation modes of a topological laser device operating in single-mode steady state with monochromatic emission. consider model based on two-dimensional photonic Harper-Hofstadter lattice including broadband gain medium localized system edge. Different regimes are considered as function value optical nonlinearity and relaxation time. The dispersion is calculated via full Bogoliubov approach physically interpreted terms an effective one-dimensional...
For a generic semiclassical laser dynamics in the complex Ginzburg-Landau form, we develop Bogoliubov approach for computation of emission linewidth. Our method provides unifying perspective treatments by Henry and Petermann: both broadening mechanisms are ascribed to nonorthogonality modes, which live space with doubled degrees freedom. As an example application, allows one study interplay drive dissipation, interactions, spatial inhomogeneity typical polariton condensates. The traditional...
Interacting bosons on a single plaquette threaded by $\pi$-flux can spontaneously break time-reversal symmetry, resulting in chiral loop current. Connecting such bosonic plaquettes dispersive configuration was recently shown to lead long-range order. Here, instead, we design chain of that exhibits an all-flat-bands single-particle energy spectrum and extensive set local symmetries. As consequence, Elitzur's theorem is prevent the emergence Moreover, projecting dynamics Creutz ladder model...
We theoretically demonstrate that the hallmarks of correlation and fermionization in a one-dimensional exciton-polaritons gas can be observed with state-of-the-art technology. Our system consists chain excitonic quantum dots coupled to photonic waveguide, low filling polaritons. analytically identify Tonks-Girardeau, Tavis-Cummings mean-field limits relate them different regimes anharmonicity bandwidth. Using matrix-product states, we numerically calculate ground-state energies, functions...
Immersing a mobile impurity in quantum many-body environment can reveal fundamental properties of the background medium, hence providing powerful probe matter. This approach is particularly intriguing when considering media with exotic properties, such as strongly-correlated phases and topological states In this work, we study dressing interacting chiral mode, provided by edge The resulting ''chiral polaron'' characterized an asymmetric spectral function, which reflects chirality group...
A mobile impurity immersed in a non-interacting Fermi sea is dressed by the gapless particle-hole excitations of fermionic medium. This conventional Fermi-polaron setting well described so-called ladder approximation, which consists neglecting impurity-hole scattering processes. In this work, we analyze polaron formation context insulating states matter, considering increasing levels correlation medium:~band insulators originating from external periodic potentials, spontaneously-formed...
In this work we study a system of interacting fermions on triangular lattice in the presence an external magnetic field. We neglect spin and fix density one third, with unit flux per particle. The infinite matrix renormalization group (iDMRG) algorithm is used to compute ground state generalized Fermi-Hubbard model. Increasing strength nearest-neighbor repulsion, find first order transition between Integer Quantum Hall phase crystalline, Wigner crystal state. first-order nature consistent...
A mobile impurity immersed in a noninteracting Fermi sea is dressed by the gapless particle-hole excitations of fermionic medium. This conventional Fermi-polaron setting well described so-called ladder approximation, which consists neglecting impurity-hole scattering processes. In this work, we analyze polaron formation context insulating states matter, considering increasing levels correlation medium: band insulators originating from external periodic potentials, spontaneously formed charge...
Detecting vortices in neutral superfluids represents an outstanding experimental challenge. Using stochastic classical-field methods, we theoretically show that a quantum impurity repulsively coupled to weakly-interacting Bose gas at finite temperature carries direct spectroscopic signatures of vortex proliferation. In two dimensions, find low-energy (attractive) branch the excitation spectrum becomes prominent when is tuned across Berezinskii-Kosterlitz-Thouless (BKT) transition. We explain...