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Welcome to the microscope lab !
Welcome to the microscope lab !
A single optical element combining ultra-high spatial resolution with single atom-single photon strong coupling !
Cavity microscope for micrometer-scale control of atom-photon interactions
Cavity microscope for micrometer-scale control of atom-photon interactions
We propose and demonstrate a cavity-microscope device capable of controlling in space and time the coupling between atoms and light in a single-mode high-finesse cavity, reaching a spatial resolution an order-of-magnitude lower than the cavity mode waist. This is achieved through local Floquet engineering of the atomic level structure, imprinting a corresponding atom-field coupling. We illustrate this capability by engineering micrometer-scale coupling, using cavity-assisted atomic measurements and optimization. Our system forms an optical device with a single optical axis and has the same footprint and complexity as a standard Fabry-Perot cavity or confocal lens pair, and can be used for any atomic species. This technique opens a wide range of perspectives from ultra-fast, cavity-enhanced mid-circuit readout to the quantum simulation of fully connected models of quantum matter such as the Sachdev-Ye-Kitaev model.
Read the paper in PRX Quantum, and the Focus article in Physics.
Engineering random spin models with atoms in a high-finesse cavity
Engineering random spin models with atoms in a high-finesse cavity
All-to-all interacting, disordered quantum many-body models have a wide range of applications across disciplines, from spin glasses in condensed-matter physics, over holographic duality in high-energy physics, to annealing algorithms in quantum computing. Typically, these models are abstractions that do not find unambiguous physical realisations in nature. Here, we realise an all-to-all interacting, disordered spin system by subjecting an atomic cloud in a cavity to a controllable light shift. Adjusting the detuning between atom resonance and cavity mode, we can tune between disordered versions of a central-mode model and a Lipkin-Meshkov-Glick model. By spectroscopically probing the low-energy excitations of the system, we explore the competition of interactions with disorder across a broad parameter range. We show how disorder in the central-mode model breaks the strong collective coupling, making the dark state manifold cross over to a random distribution of weakly-mixed light-matter, "grey", states. In the Lipkin-Meshkov-Glick model the ferromagnetic finite-size ground state evolves towards a paramagnet as disorder is increased. In that regime, semi-localised eigenstates emerge, as we observe by extracting bounds on the participation ratio. These results present significant steps towards freely programmable cavity-mediated interactions for the design of arbitrary spin Hamiltonians.
Read the paper in Nature Physics
A cavity quantum-electrodynamics implementation of the Sachdev-Ye-Kitaev model
A cavity quantum-electrodynamics implementation of the Sachdev-Ye-Kitaev model
The search for a quantum theory of gravity has led to the discovery of quantum many-body systems that are dual to gravitational models with quantum properties. The perhaps most famous of these systems is the Sachdev-Ye-Kitaev (SYK) model. It features maximal scrambling of quantum information, and opens a potential inroad to experimentally investigating aspects of quantum gravity. A scalable laboratory realisation of this model, however, remains outstanding. Here, we propose a feasible implementation of the SYK model in cavity quantum electrodynamics platforms...
Read the preprint in arXiv
Multifractality in the interacting disordered Tavis-Cummings model
Multifractality in the interacting disordered Tavis-Cummings model
We analyze the spectral and transport properties of the interacting disordered Tavis-Cummings model at half excitation filling. We demonstrate that a poissonian level statistics coexists with eigenfunctions that are multifractal (extended, but non-ergodic) in the Hilbert space, for all strengths of light-matter interactions. This is associated with a lack of thermalization for a local perturbation, which remains partially localized in the infinite-time limit. We argue that these effects are due to the combination of finite interactions and integrability of the model. We propose a realization of this model with cold atoms.
Read the paper in Phys. Rev. B
Vibration damping platform for cavity-quantum electrodynamics experiments
Vibration damping platform for cavity-quantum electrodynamics experiments
We present a mechanical platform with enhanced vibration damping properties for cavity quantum-electrodynamics experiments. It is based on a composite design that combines a soft, vibration-damping core with a rigid shell maintaining optical alignment. It passively damps the vibrations generated by piezoelectric actuators controlling the mirror positions. The mechanical resonances of the platform, which lead to a length change of the cavity are efficiently suppressed up to 100 kHz. Our platform is ultra-high vacuum compatible and can be used in most applications, in particular where long cavities and optical access to the cavity center are required.
Read the paper in Review of Scientific Instruments
A tour to our experimental platform
A tour to our experimental platform
Click and explore the 3D drawings of our experiment !
Start with the overview of the system and follow the atoms from the lithium oven down to the center of our high-finesse cavity
Explore our science platform, with high reflectivity mirrors and aspherical lenses attached to them. Take a look at the vibration damping platform holding this system !
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