We welcome all the young physicists to this 2022 edition of the RJP!
We demonstrate the effectiveness of optomechanical devices for the measurement of individual nanoparticles. A semiconductor optomechanical disk resonator is optically driven and detected under ambient conditions, as nebulized nanoparticles land on it. Multiple mechanical and optical resonant signals of the disk are tracked simultaneously, providing access to several pieces of physical...
Odonata (dragonfly and damselfly) exhibit impressive flight ability. They are able to perform many different maneuvers such as zigzag, linear motion back and forth, sharp turn, quick acceleration. These trajectories are the result of complex fluid-structure interactions. Wing morphology has a main role in this interaction as shown in previous studies.
Insect wings, including dragonfly wings,...
The cocktail party effect is the capability to focus one's auditory attention on particular audio sources while ignoring other audio sources. We propose an experimental setup reproducing the cocktail party effect by designing a time dependent metasurface composed of independent active mirrors. Each active mirror is a programmable acoustical unit cell capable of hearing, computing and emitting...
Adaptive immunity’s success relies on the extraordinary diversity of protein receptors on B and T cell membranes. Despite this diversity, the existence of public receptors shared by many individuals gives hope for developing population wide vaccines and therapeutics. Yet many of these public receptors are shared by chance. We present a statistical approach, defined in terms of a probabilis tic...
A great challenge in numerical simulations of geophysical systems (such as in climate models) is the important range of relevant scales. In particular in fluid dynamics, it is impossible to do Direct Numerical Simulations of the whole system, and one has to resort to a variety of numerical tricks.
We present a new method, “Logarithmic Lattices”, which aims at simulating very important...
In November 1572, a nearby star exploded in a supernova and was observed at the time by Tycho Brahe. Exactly 450 years later, we can study its remnant, the huge cloud made of all the matter of the star ejected at high speeds. The ejected material is heated to tens of millions Kelvin and radiates most of its energy in the X-ray (0.1-10 keV) band.
Currently, the Chandra X-ray telescope...
Nearly a year ago, the most expensive space telescope ever built was launched into space. After traveling for 6 months, it began to explore the infra-red universe in June. In 4 months, JWST's extraordinary spatial resolution already allowed groundbreaking discoveries in the field of galaxy formation and evolution. From the first detection of extremely old galaxies (back when the universe was...
Strong lensing -- the effect of light being bent by massive objects such as galaxies and forming circular ring-like images -- is one of the most striking phenomena in observational cosmology. If multiple images are observed, they be used to measure cosmological distances and the expansion rate of the Universe. However, strong lensing images are often distorted by other nearby galaxies or...
After the recent discovery of the massive nature of neutrinos, through the observation of their oscillations, we now enter an era of precision measurement of the oscillation parameters. The next long-baseline neutrino accelerator experiments will be crucial for these precision measurements and will need to feature innovative detector technologies that offer high target mass (to acquire large...
Gamma-ray bursts (GRBs) are an amazing class of transient phenomena in the Universe. GRBs are detected from space by satellites thanks to the flash of gamma-ray photons released within an ultra-relativistic jet. The jet is thought to be produced by a new-born accreting black hole formed after the collapse of a massive star, Long-GRBs (LGRBs), or the merger of two compact objects, Short-GRBs...
Understanding the atmospheric circulation, radiative transfer and atmo-
spheric chemistry of exoplanets is crucial for our understanding of these objects.
In particular, Hot Jupiters are among the most observed type of exoplanets and
have no equivalent in our Solar System. During the last decade, observational
and modelling efforts have been made to begin the atmospheric...
The strongly correlated material $VO_2$ displays a metal-to-insulator (MIT) transition when going below $T_{MIT}=280K$. Alongside this electronic transition, the material undergoes a structural transition from a rutile structure in the metallic phase to a monoclinic structure in the insulating phase. These simultaneous transitions have created a long-lasting debate within the community: is the...
The inverse Faraday effect (IFE) allows the generation of stationary magnetic fields through optical excitation only [1,2]. This light−matter interaction in metals results from the creation of drift currents via nonlinear forces that light applies to the conduction electrons [1]. The IFE was believed, until now, to be a symmetrical phenomenon, meaning that a right-handed circularly polarized...
PtSe2 is a promising 2D material for high frequency IR optoelectronics [1], its bandgap varying from 1.2 eV (monolayer) to 0.2 eV (bilayer) [2]. We have grown 2D PtSe2 films on sapphire(0001) substrates by molecular beam epitaxy. In particular, we used sapphire substrates with a 0.25° miscut to generate, after high temperature (1135°C) annealing, stepped structures. Indeed, we demonstrated...
WTe2, a transition metal dichalcogenide, is predicted to have striking topological properties that combine the characters of type II Weyl semimetal and second-order 3D topological insulator (SOTI). SOTIs are characterized by topologically protected helical 1D states at their hinges. 1D states located at certain edges of multilayer WTe2 have indeed been demonstrated in Josephson interferometry...
DNA toroids are complex liquid crystalline objects that form spontaneously in vitro by condensation of DNA, a general behaviour of semi-flexible polyelectrolytes. These structures have intrigued biophysicists and physicists, both experimental and theoretical, because of the intrinsic beauty of these toroidal objects, and because they provide models for understanding the packaging of DNA in...
To explain the open questions in the fundaments of physics, new theories that reach beyond the standard model of particle physics are needed. A great number of these indirectly predict electric dipole moments (EDM) of fundamental particles in ranges that are just within reach for modern atomic and molecular physics experiments. While measurements in atomic and molecular beams provided the most...
Trapping cold neutral atoms in close proximity to nanostructures has raised a large interest in recent years, pushing the frontiers of cavity-QED and boosting the emergence of the waveguide-QED field of research. Such platforms interfacing trapped cold atoms and guided light in nanoscale waveguides are a promising route to achieve a regime of strong coupling between light and atoms, and...
Quantum field theory (QFT) was developed in the 1940s as a theoretical framework for particle physics by combining classical field theory, special relativity and quantum mechanics. In the context of elementary particle physics, QFT provides various tools to accurately determine multiple physical quantities. The most used are essentially perturbative calculations via Feynman diagrams, as well...
Quantum gravity is one of the biggest riddle of our time. One approach to it is the Causal Set Theory (CST) that aims to unify the framework of General Relativity and Quantum Mechanics by the concept of proto-causality. We will explore how the classical spacetime continuum can emerge from the discrete structure of a network of fundamental elements, and how reasoning at this smallest scale of...
One of the main goals of physical theories is to provide a useful, universal, effective description of many-body quantum systems at macroscopic scales, regardless of the complicated microscopic dynamics. This is achieved in the context of hydrodynamic effective field theories at finite temperature, by focussing on the dynamics of conserved charges, corresponding to symmetries of the theory,...
