M. Karam Ouharou

Abstract Element isotopes are characterized by distinct atomic masses and nuclear spins, which can significantly influence material properties. Notably, however, isotopes in natural materials are homogenously distributed in space. Here, we propose a method to configure material properties by repositioning isotopes in engineered van der Waals (vdW) isotopic heterostructures. We showcase the properties of hexagonal boron nitride (hBN) isotopic heterostructures in engineering confined photon-lattice waves—hyperbolic phonon polaritons. By varying the composition, stacking order, and thicknesses of h 10 BN and h 11 BN building blocks, hyperbolic phonon polaritons can be engineered into a variety of energy-momentum dispersions. These confined and tailored polaritons are promising for various nanophotonic and thermal functionalities. Due to the universality and importance of isotopes, our vdW isotope heterostructuring method can be applied to engineer the properties of a broad range of mater...

Introduction : Magnetic topological insulators and semimetals are a class of crystalline solids whose properties are strongly influenced by the coupling between non-trivial electronic topology and magnetic spin configurations. Such materials can host exotic electromagnetic responses. Among these are topological insulators with certain types of antiferromagnetic order which are predicted to realize axion electrodynamics. Here we investigate the highly unusual helimagnetic phases recently reported in EuIn 2 As 2 , which has been identified as a candidate for an axion insulator. Using resonant elastic x-ray scattering we show that the two types of magnetic order observed in EuIn 2 As 2  are spatially uniform phases with commensurate chiral magnetic structures, ruling out a possible phase-separation scenario, and we propose that entropy associated with low energy spin fluctuations plays a significant role in driving the phase transition between them. Our results establish that the magn...

Figure 1 Abstract: The interplay between time-reversal symmetry breaking and strong light–matter coupling in two-dimensional (2D) gases brings intriguing aspects to polariton physics. This combination can lead to a polarization/spin-selective light–matter interaction in the strong coupling regime. Here we report such a selective strong light–matter interaction by harnessing a 2D gas in the quantum Hall regime coupled to a microcavity. Specifically, we demonstrate circular-polarization dependence of the vacuum Rabi splitting, as a function of magnetic field and hole density. We provide a quantitative understanding of the phenomenon by modelling the coupling of optical transitions between Landau levels to the microcavity. This method introduces a control tool over the spin degree of freedom in polaritonic semiconductor systems, paving the way for new experimental possibilities in light–matter hybrids. **1. Introduction** The field of strong light-matter coupling has captivated researcher...

Abstract : The study of cold and controlled molecular ions has been of key importance for a1 wide range of applications, such as the production of cold antihydrogen, creation and study of anionic Coulomb crystals and in atmospheric research and astrochemistry. However, the commonly used anion cooling technique via collisions with a buffer gas is limited by the temperature of the used cryogenic cooling medium. Here we demonstrate the forced evaporative cooling of anions via a laser beam with photon energies far above the photodetachment threshold of the anion. We cool an anionic ensemble from an initial temperature of 370(12) K down to 2.2(8) K. This results in a three orders of magnitude increase in the phase-space density of the ions, approaching the near-strong Coulomb coupling regime. We present an analysis of the cooling dynamics through a thermodynamic model that includes the role of intrinsic collisional heating, without any fitting parameters. This technique can be used to cool...

Radioactive nuclei have long captured the attention of physicists due to their inherently unstable nature. The behavior of these nuclei challenges our understanding of the fundamental principles governing the subatomic world. A recent breakthrough in the study of radioactive nuclei involves the discovery of a long-lived quantum state, which holds the promise of shedding light on a perplexing mystery within this realm. This article delves into the significance of this discovery and its potential implications for unraveling the enigma of radioactive nuclei. At the heart of the mystery lies the behavior of certain radioactive nuclei that exhibit unexpected properties. Specifically, researchers have observed instances where certain nuclei persist in a seemingly stable state for much longer than theoretical predictions would suggest. This phenomenon has puzzled physicists for decades, as it defies conventional understanding of nuclear decay processes. However, the recent identification of a...

Abstract : This groundbreaking research introduces a revolutionary hardware architecture that unveils a novel paradigm in quantum computing. Leveraging innovative qubit designs and advanced control mechanisms, the study presents a quantum computing model that promises unprecedented levels of computational power and scalability. Through comprehensive theoretical analyses, experimental validations, and performance evaluations, we demonstrate the viability and potential of this cutting-edge approach, marking a significant advancement in the realm of quantum computing technologies. Quantum computing has emerged as a frontier technology with transformative potential across various scientific and industrial domains. This research introduces a revolutionary hardware architecture that transcends existing limitations and opens doors to a new quantum computing model. By harnessing unique qubit designs and sophisticated control strategies, we address critical challenges while offering enhanced co...

Abstract : This research article delves into the intricate realm of aerodynamic interactions between liquid drops and parallel fibrous structures, with a primary focus on elucidating the underlying mechanisms governing their behavior. The study combines theoretical analysis, numerical simulations, and experimental observations to provide a multidimensional exploration of this phenomenon. Through a profound investigation, we unveil the complex interplay of forces, surface tension, fluid dynamics, and fiber morphology, shedding light on the intricate dynamics governing drop-fiber interactions. Our findings contribute to a deeper understanding of fundamental fluid mechanics and offer potential applications in diverse fields ranging from materials science to industrial processes. The wetting behaviour of drops on rigid and elastic fibres is important in many applications including textiles, fog collection, systems with absorbent fibres, and in natural settings such as spiderwebs. Yet, litt...