Publications associées à BCS-BEC crossover in two dimensions: a Quantum Monte Carlo study

Density-wave ordering in a unitary Fermi gas with photon-mediated interactions

Jean-Philippe Brantut, Victor Youri Helson, Kevin Etienne Robert Roux, Hideki Konishi, Timo Zwettler, Elvia Colella

A density wave (DW) is a fundamental type of long-range order in quantum matter tied to self-organization into a crystalline structure. The interplay of DW order with superfluidity can lead to complex scenarios that pose a great challenge to theoretical an ...

NATURE PORTFOLIO2023

Correlation properties of a one-dimensional repulsive Bose gas at finite temperature

Riccardo Rota

We present a comprehensive study shedding light on how thermal fluctuations affect correlations in a Bose gas with contact repulsive interactions in one spatial dimension. The pair correlation function, the static structure factor, and the one-body density ...

IOP Publishing Ltd2023

Characterization of two electronic subsystems in cuprates through optical conductivity

Neven Barisic, Ana Akrap, Edoardo Martino

Understanding the physical properties of unconventional superconductors as well as of other correlated materials presents a formidable challenge. Their unusual evolution with doping, frequency, and temperature has frequently led to non-Fermi-liquid (non-FL ...

2023

Grand canonical Brownian dynamics simulations of adsorption and self-assembly of SAS-6 rings on a surface

Pierre Gönczy, Niccolo Banterle

The Spindle Assembly Abnormal Protein 6 (SAS-6) forms dimers, which then self-assemble into rings that are critical for the nine-fold symmetry of the centriole organelle. It has recently been shown experimentally that the self-assembly of SAS-6 rings is st ...

AIP Publishing2023

Many-body physics with strongly interacting fermions coupled to light

Victor Youri Helson

This thesis reports on the realization of the first experiments conducted with superfluid, strongly interacting Fermi gases of 6Li coupled to the light field of an optical cavity. In the scope of existing ultracold atomic platforms, this is the first time ...

EPFL2023

Optomechanical response of a strongly interacting Fermi gas

Jean-Philippe Brantut, Victor Youri Helson, Kevin Etienne Robert Roux, Hideki Konishi, Timo Zwettler

We study a Fermi gas with strong, tunable interactions dispersively coupled to a high-finesse cavity. Upon probing the system along the cavity axis, we observe a strong optomechanical Kerr nonlinearity originating from the density response of the gas to th ...

AMER PHYSICAL SOC2022

Cavity Quantum Electrodynamics with strongly correlated fermions

Kevin Etienne Robert Roux

This thesis presents the first cavity quantum electrodynamics experiments performed with a degenerate gas of

^6

Li with strong atom-atom interactions. The first part of this manuscript describes the design and the building of the apparatus that has been e ...

EPFL2022

Hole-induced anomaly in the thermodynamic behavior of a one-dimensional Bose gas

Riccardo Rota

We reveal an intriguing anomaly in the temperature dependence of the specific heat of a one-dimensional Bose gas. The observed peak holds for arbitrary interaction and remembers a superfluid-to-normal phase transition in higher dimensions, but phase transi ...

SCIPOST FOUNDATION2022

State selective cooling of SU(N) Fermi gases

Frédéric Mila, Miklos Lajko

We investigate a species selective cooling process of a trapped SU(N) Fermi gas using entropy redistribution during adiabatic loading of an optical lattice. Using high-temperature expansion of the Hubbard model, we show that when a subset N-A < N of the si ...

2021

Cavity-assisted preparation and detection of a unitary Fermi gas

Jean-Philippe Brantut, Victor Youri Helson, Kevin Etienne Robert Roux, Hideki Konishi

We report on the fast production and weakly destructive detection of a Fermi gas with tunable interactions in a high finesse cavity. The cavity is used both with far off-resonant light to create a deep optical dipole trap, and with near-resonant light to r ...

2021

From hidden order to antiferromagnetism: Electronic structure changes in Fe-doped URu2Si2

Emmanouil Frantzeskakis, Kevin Huang, Ji Dai

In matter, any spontaneous symmetry breaking induces a phase transition characterized by an order parameter, such as the magnetization vector in ferromagnets, or a macroscopic many electron wave function in superconductors. Phase transitions with unknown o ...

National Academy of Sciences2021

Weakness of Correlation Effect Manifestation in BaNi2As2: An ARPES and LDA plus DMFT Study

Daniil Yevtushynsky, Timur Kim

The electronic spectral function of BaNi2As2 is investigated using both angle-resolved photoemission spectroscopy (ARPES) and a combined computational scheme of local density approximation and dynamical mean-field theory (LDA + DMFT). In contrast to the we ...

AMER CHEMICAL SOC2021

Role of a higher-dimensional interaction in stabilizing charge density waves in quasi-one-dimensional NbSe3 revealed by angle-resolved photoemission spectroscopy

Christophe Berthod, Helmuth Berger

We revisit charge density wave (CDW) behavior in the archetypal quasi-one-dimensional (quasi-1D) material NbSe3 by high-resolution angle-resolved photoemission spectroscopy measurements utilizing a microfocused laser with a photon energy of 6.3 eV. We pres ...

2020

Quantum interference effects of out-of-plane confinement on two-dimensional electron systems in oxides

Emmanouil Frantzeskakis, Ji Dai

It was recently discovered that a conductive, metallic state is formed on the surface of some insulating oxides. First observed on SrTiO3 (001), it was then found in other compounds as diverse as anatase TiO2, KTaO3, BaTiO3, ZnO, and also on different surf ...

2020

Light-Induced Renormalization of the Dirac Quasiparticles in the Nodal-Line Semimetal ZrSiSe

Helmuth Berger, Philippe Bugnon, Marco Grioni, Majed Chergui, Arnaud Magrez, Luca Moreschini, Alberto Crepaldi, Simon Karl Moser, Gianmarco Gatti, Serhii Polishchuk, Michele Puppin

In nodal-line semimetals, linearly dispersing states form Dirac loops in the reciprocal space with a high degree of electron-hole symmetry and a reduced density of states near the Fermi level. The result is reduced electronic screening and enhanced correla ...

2020

Dimensional crossover in the SU(4) Heisenberg model in the six-dimensional antisymmetric self-conjugate representation revealed by quantum Monte Carlo and linear flavor-wave theory

Frédéric Mila, Karlo Penc, Francisco Hyunkyu Kim

Using linear flavor-wave theory (LFWT) and auxiliary field quantum Monte Carlo (QMC), we investigate the properties of the SU(4) Heisenberg model on the anisotropic square lattice in the fully antisymmetric six-dimensional irreducible representation, a mod ...

2019

Scaling of the superconducting gap with orbital character in FeSe

Timur Kim

We use high-resolution angle-resolved photoemission spectroscopy to map the three-dimensional momentum dependence of the superconducting gap in FeSe. We find that on both the hole and electron Fermi surfaces, the magnitude of the gap follows the distributi ...

2018

Band and Correlated Insulators of Cold Fermions in a Mesoscopic Lattice

Jean-Philippe Brantut, Thierry Giamarchi, Samuel Häusler

We investigate the transport properties of neutral, fermionic atoms passing through a one-dimensional quantum wire containing a mesoscopic lattice. The lattice is realized by projecting individually controlled, thin optical barriers on top of a ballistic c ...

American Physical Society2018

Breakdown of the Wiedemann-Franz law in a unitary Fermi gas

Jean-Philippe Brantut, Samuel Häusler

We report on coupled heat and particle transport measurements through a quantum point contact (QPC) connecting two reservoirs of resonantly interacting, finite temperature Fermi gases. After heating one of them, we observe a particle current flowing from c ...

National Academy of Sciences2018

Nodeless superconductivity in the noncentrosymmetric Mo3Rh2N superconductor: A mu SR study

Joël Mesot

The noncentrosymmetric superconductor Mo3Rh2N, with T-c = 4.6 K, adopts a beta-Mn-type structure (space group P4(1)32), similar to that of Mo3Al2C. Its bulk superconductivity was characterized by magnetization and heat-capacity measurements, while its micr ...

AMER PHYSICAL SOC2018