Publications related to Coherence properties of exciton polariton OPO condensates in one and two dimensions

Learning the intrinsic dynamics of spatio-temporal processes through Latent Dynamics Networks

Alfio Quarteroni, Francesco Regazzoni, Stefano Pagani

Predicting the evolution of systems with spatio-temporal dynamics in response to external stimuli is essential for scientific progress. Traditional equations-based approaches leverage first principles through the numerical approximation of differential equ ...

Nature Portfolio2024

Identifying Large Charge operators

Riccardo Rattazzi, Alexander Monin, Gil Badel

The Large Charge sector of Conformal Field Theory (CFT) can generically be described through a semiclassical expansion around a superfluid background. In this work, focussing on U(1) invariant Wilson-Fisher fixed points, we study the spectrum of spinning l ...

Springer Nature2023

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

Semiclassical methods in conformal field theories scrutinized by the epsilon-expansion

Gil Badel

Conformal Field Theories (CFTs) are crucial for our understanding of Quantum Field Theory (QFT). Because of their powerful symmetry properties, they play the role of signposts in the space of QFTs. Any method that gives us information about their structure ...

EPFL2022

High sensitivity, incoherent differential imaging

Chiara Bonati

Microscopic visualisation of optically transparent samples has been a topic of interest for several decades. Features such as density or chemical composition can influence the optical phase of transmitted light, and phase contrast can reveal these structur ...

EPFL2022

Light Dark Matter and Superfluid He-4 from EFT

Angelo Esposito

We study the response of a He-4 detector to the interaction of sub-GeV dark matter using an effective field theory for the superfluid. We compute the lifetime of the phonon, which agrees with what known from standard techniques, hence providing an importan ...

IOP PUBLISHING LTD2020

Angular Momentum in Rotating Superfluid Droplets

Camila Bacellar Cases Da Silveira, Christoph Bostedt

The angular momentum of rotating superfluid droplets originates from quantized vortices and capillary waves, the interplay between which remains to be uncovered. Here, the rotation of isolated submicrometer superfluid He-4 droplets is studied by ultrafast ...

AMER PHYSICAL SOC2020

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

Superfluids, vortices and spinning charged operators in 4d CFT

Gabriel Francisco Cuomo

We include vortices in the superfluid EFT for four dimensional CFTs at large global charge. Using the state-operator correspondence, vortices are mapped to charged operators with large spin and we compute their scaling dimensions. Different regimes are ide ...

Springer Nature2020

Dark matter, dark photon and superfluid He-4 from effective field theory

Emma Michèle Ginette Geoffray, Angelo Esposito

We consider a model of sub-GeV dark matter whose interaction with the Standard Model is mediated by a new vector boson (the dark photon) which couples kinetically to the photon. We describe the possibility of constraining such a model using a superfluid He ...

2020

Sub-GeV dark matter in superfluid He-4: an effective theory approach

Angelo Esposito

We employ an effective field theory to study the detectability of sub-GeV dark matter through its interaction with the gapless excitations of superfluid 4He. In a quantum field theory language, the possible interactions between the dark matter and the supe ...

Springer2019

High spatial resolution and intrinsically strain-insensitive distributed temperature sensing based on stimulated Brillouin scattering in gas

Luc Thévenaz, Flavien Gyger

Temperature/strain cross sensitivity is a long-standing issue in Brillouin-based distributed sensors, impairing the reliability of such sensors. So far, all the proposed methods perform the discrimination by measuring two quantities showing distinct respon ...

SPIE2019

Polaritonic Cross Feshbach Resonance

Daniel Oberli, Marcia Portella Oberli, Naotomo Takemura, Mitchell David Anderson, Morteza Navadeh Toupchi

We demonstrate the existence of a cross Feshbach resonance by strongly driving a lower polariton mode and by monitoring in time the transmission of a short optical pulse at the energy of the upper polariton mode in a semiconductor microcavity. From the sig ...

2019

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

Low-dimensional data embedding for scalable astronomical imaging in the SKA telescope era

Vijay Kartik

Astronomy is one of the oldest sciences known to humanity. We have been studying celestial objects for millennia, and continue to peer deeper into space in our thirst for knowledge about our origins and the universe that surrounds us. Radio astronomy -- ob ...

EPFL2018

Local resilience of the 1T-TiSe2 charge density wave to Ti self-doping

Helmuth Berger, Philipp Aebi, Elia Razzoli

In Ti-intercalated self-doped 1T-TiSe2 crystals, the charge density wave (CDW) superstructure induces two nonequivalent sites for Ti dopants. Recently, it has been shown that increasing Ti doping dramatically influences the CDW by breaking it into phase-sh ...

Amer Physical Soc2017

Sparse inverse problems for Fourier imaging : applications to Optical Interferometry and Diffusion Magnetic Resonance Imaging

Anna Auria Rasclosa

Many natural images have low intrinsic dimension (a.k.a. sparse), meaning that they can be represented with very few coefficients when expressed in an adequate domain. The recent theory of Compressed Sensing exploits this property offering a powerful frame ...

EPFL2017

Mastering the statistical properties of microcavity polaritons

Albert Adiyatullin

Microcavity polaritons are hybrid quasiparticles emerging from the strong coupling between quantum well excitons and light in the resonator. Their unique half-light half-matter nature brings in specific properties like low effective mass, nonlinearity due ...

EPFL2017

Coherent imaging from bacteria to multicellular organisms

Séverine Coquoz

Structural and functional imaging of cells, tissues and organisms is crucial for understanding biomedical processes. Fluorescence microscopy is an established tool and has contributed to many discoveries in the life sciences. This technique provides molecu ...

EPFL2017

Fourier dimensionality reduction of radio-interferometric data

Jean-Philippe Thiran, Yves Wiaux, Rafael Eduardo Carrillo Rangel, Vijay Kartik

Next-generation radio-interferometers face a computing challenge with respect to the imaging techniques that can be applied in the big data setting in which they are designed. Dimensionality reduction can thus provide essential savings of computing resourc ...

2017