Josephson waveguides have recently emerged as very promising platform for superconducting quantum science and technologies. Their distinguishing potential resides in ability to engineer them at sub-wavelength scales, which allows complete control over wave dispersion and nonlinear interaction. In this talk I will discuss a Josephson waveguide with strong third order nonlinearity, which can be...
Nowadays, the state-of-the-art chip-scale phononic-crystal membranes can achieve lifetimes over 100 s and coherence times in the order of seconds in a thermal environment at 10 mK. [1]. It can be achieved using softly-clamped silicon-nitride membranes (typically in MHz frequency range). The strong coupling between these outstanding mechanical resonators and the superconducting qubits...
Electron spin resonance (ESR) spectroscopy is the method of choice for characterizing paramagnetic impurities in a sample, with applications ranging from chemistry to quantum computing but it gives access only to ensemble-averaged quantities due to its limited signal-to-noise ratio. Here, we report a new method for the detection of single electron spins at millikelvin temperatures. Analogous...
Les ions de terre rare en matrice cristalline sont aujourd'hui au coeur d'intenses efforts de recherche fondamentale et appliquée, relevant des technologies quantiques (mémoires optiques, mémoires micro-ondes, transduction optique-micro-ondes, calcul quantique), mais aussi du traitement de signaux (analyse spectrale de signaux radio-fréquence, retournement temporel, ou encore filtrage). Dans...
Since their discovery, black holes have motivated many theoretical works in the framework of general relativity, where the curvature of spacetime and trajectory of particles are of particular interest. Furthermore, they have also driven the theoretical study of quantum field effects such as Hawking radiation or rotational superradiance, although these remain unobserved due to their very weak...
Les technologies quantiques ont le potentiel d'améliorer d’une manière inédite la sécurité et l'efficacité des communications dans les infrastructures de réseau. Dans cet exposé, nous discutons du paysage actuel de la communication et de la cryptographie quantiques, et nous nous concentrons en particulier sur des implémentations photoniques des protocoles de réseaux quantiques, permettant la...
High dimensional quantum states, qudits, leverage the ability to store more information in a single photon. They can be used for quantum computing and quantum cryptography, as they are also enable more tolerant to noise [1]. Frequency domain, for example, grants access to a high dimensional Hilbert space. It is furthermore compatible with integration and can leverage multiplexing, since all...
The field of quantum information consists in exploiting quantum superposition of information bits to bring new perspectives for multiple applications such as quantum communications or quantum computing. Our team works on the development of one possible way to encode quantum information with light. Indeed, it is possible to use coherent state coding, with optical Schrödinger cat states, as a...
Summary
Integrated quantum photonics is a key tool towards large scale quantum technologies. In this work we present an AlGaAs-based photonic circuit for on-chip generation and manipulation of broadband orthogonally polarized photon pairs [1]. Among different platforms used for the development of quantum photonic chips AlGaAs is extremely interesting for integrability [2]. This material...
Engineering quantum states of free-propagating light is of paramount importance for quantum technologies. Coherent states ubiquitous in classical and quantum communications, squeezed states used in quantum sensing, and even highly-entangled cluster states studied in the context of quantum computing can be produced deterministically, but they obey quasi-classical optical field statistics...
This talk will present our recent work on the use of arrays of Rydberg atoms to study quantum magnetism and to generate entangled states useful for quantum metrology. We rely on laser-cooled ensembles of up to hundred individual atoms trapped in microscopic optical tweezer arrays. By exciting the atoms into Rydberg states, we make them interact by the resonant dipole interaction. The system...
Atom interferometers are exquisite tools for force measurements such as gravity. However, state-of-the-art such sensors use free-falling atoms and hence cannot perform purely local force measurements. Instead, we use here optically trapped atoms to perform force sensing close to the surface of a mirror and probe with unprecedented sensitivity atom-surface interactions.
We start with a...
Les horloges à réseau optique sont des étalons de fréquence qui utilisent une transition optique de grand facteur de qualité dans un ensemble d'atomes froids dans un piège dipolaire. Elles offrent maintenant des incertitudes statistiques et systématiques proches de 10⁻¹⁸, avec des applications en physique fondamentale, en géodésie... À ce niveau de performances, le bruit quantique devient une...
The Hall effect, which originates from the motion of charged particles in a magnetic field, has deep consequences for the description and characterization of materials, extending far beyond the original context of condensed matter physics. Although the Hall effect for non-interacting particles is well explained, understanding it in interacting systems still represents a fundamental challenge...
We experimentally study quantum magnetism using interacting spin systems made of lattice trapped magnetic atoms. The dipolar interactions between spins frozen on lattice sites gives rise to a beyond mean field spin dynamics, after excitation in an out of equilibrium initial state. This dynamic leads to a steady state compatible with the ETH scenario of quantum thermalization, in which the...
Analogue Gravity is a type of analogue quantum simulation that aims at observing effects initially predicted by quantum field theory on curved spacetime, such as the Hawking effect and rotational superradiance, in systems at laboratory scales with similar dynamics [1].
The high tunability of such systems enables to shed light on phenomena that are either currently eluding our comprehension...
