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Procédé de mesure de la force d’interaction entre une portion et une pointe d’une sonde de force d’un AFM solidaire d’un moyen d’excitation, le moyen d’excitation étant apte à vibrer en fonction d’un signal d’excitation e(t), le procédé comprenant une étape de mise en excitation de la sonde de force, un signal d’excitation étant appliqué configuré pour engendrer, une déflexion libre s0(t) formant un signal sinusoïdal modulé en amplitude par une impulsion, la sonde de force entrant en résonance à une fréquence de résonance libre f_0, une étape de mesure de la déflexion s(t), la sonde de force entrant en résonance à une fréquence de résonance d’interaction f_T, une étape de traitement dans laquelle est évalué un décalage fréquentiel Δf_T, différence entre la fréquence de résonance d’interaction de la sonde de force, et la fréquence de résonance libre.
The effective control of atomic coherence with cold atoms has made atom interferometry an essential tool for quantum sensors and precision measurements. The performance of these interferometers is closely related to the operation of large wave packet separations. We present here a novel approach for atomic beam splitters based on the stroboscopic stabilization of quantum states in an accelerated optical lattice. The corresponding Floquet state is generated by optimal control protocols. In this way, we demonstrate an unprecedented Large Momentum Transfer (LMT) interferometer, with a momentum separation of 600 photon recoils ($600\hbar k$) between its two arms. Each LMT beam splitter is realized in a remarkably short time (2 ms) and is highly robust against the initial velocity dispersion of the wave packet and lattice depth fluctuations. Our study shows that Floquet engineering is a promising tool for exploring new frontiers in quantum physics at large scales, with applications in quantum sensing and testing fundamental physics.
We numerically study the optimal control of an atomic Bose-Einstein condensate in an optical lattice. We present two generalizations of the gradient-based algorithm, GRAPE, in the non-linear case and for a two-dimensional lattice. We show how to construct such algorithms from Pontryagin’s maximum principle. A wide variety of target states can be achieved with high precision by varying only the laser phases setting the lattice position. We discuss the physical relevance of the different results and the future directions of this work.
Microscopically probing quantum many-body systems by resolving their constituent particles is essential for understanding quantum matter. In most physical systems, distinguishing individual particles, such as electrons in solids, or neutrons and quarks in neutron stars, is impossible. Atombased quantum simulators offer a unique platform that enables the imaging of each particle in a many-body system. Until now, however, this capability has been limited to quantum systems in discretized space such as optical lattices and tweezers, where spatial degrees of freedom are quantized. Here, we introduce a novel method for imaging atomic quantum many-body systems in the continuum, allowing for in situ resolution of every particle. We demonstrate the capabilities of our approach on a two-dimensional atomic Fermi gas. We probe the density correlation functions, resolving their full spatial functional form, and reveal the shape of the Fermi hole arising from Pauli exclusion as a function of temperature. Our method opens the door to probing strongly-correlated quantum gases in the continuum with unprecedented spatial resolution, providing in situ access to spatially resolved correlation functions of arbitrarily high order across the entire system.
In the absence of external forcing, all trajectories on the phase plane of the van der Pol oscillator tend to a closed, periodic, trajectory -- the limit cycle -- after infinite time. Here, we drive the van der Pol oscillator with an external time-dependent force to reach the limit cycle in a given finite time. Specifically, we are interested in minimising the non-conservative contribution to the work when driving the system from a given initial point on the phase plane to any final point belonging to the limit cycle. There appears a speed limit inequality, which expresses a trade-off between the connection time and cost -- in terms of the non-conservative work. We show how the above results can be { generalized to the broader family of non-linear oscillators given by} the Liénard equation. Finally, we also look into the problem of minimising the total work done by the external force.
Sujets
Espace des phases
Chaos-assisted tunneling
Condensats de Bose– Einstein
Optical lattices
Hamiltonian
Engineering
Plasmon polariton de surface
Bose-Einstein
Approximation semi-classique et variationnelle
Quantum chaos
Fluorescence microscopy
Atom chip
Bose–Einstein condensates
Gaz quantiques
Optique atomique
Optimal control theory
Césium
Condensat de Bose-Einstein
Numerical methods
Réseau optique
Fluid
Dimension
Atom laser
Gaz quantique
Lattice
Bose Einstein condensate
Bose-Einstein Condensates
Piège magnéto-optique à miroir
Lentille de Fresnel
Contrôle optimal
Chaos quantique
Quantum
Quantum collisions
Experimental results
Atomic beam
Optical lattice
Floquet theory
Réseaux optiques
Mélasse optique
Chaos
Collisions ultrafroides
Bose-Einstein condensates
Effet rochet
Fresnel lens
Phase space
Dynamical tunneling
Ouvertures métalliques sub-longueur d'onde
Electromagnetic field
Condensation
Puce atomique
Field equations stochastic
Effet tunnel assisté par le chaos
Atomes froids
Atom optics
Quantum optimal control
Couches mono-moléculaire auto assemblées
Optical molasses
Matter waves
Bose-Einstein Condensate
Diffraction de Bragg
Ultracold atoms
Jet atomique
Masques matériels nanométriques
Cold atoms
Condensat Bose-Einstein
Physique quantique
Atomes ultrafroids dans un réseau optique
Mechanics
Mirror-magneto-optical trap
Maxwell's demon
Contrôle optimal quantique
Condensats de Bose Einstein
Current
Non-adiabatic regime
Nano-lithographie
Constraint
Onde de matière
Initial state
Entropy production
Beam splitter
Condensation de bose-Einstein
Matter wave
Théorie de Floquet
Effet tunnel dynamique
Microscopie de fluorescence
Periodic potentials
Quantum control
Bose-Einstein condensate
Bose-Einstein condensates Coherent control Cold atoms and matter waves Cold gases in optical lattices
Optical tweezers
Nano-lithography
Optical
Time dependence
Bragg Diffraction
Bose Einstein Condensation
Bragg scattering
Condensats de Bose-Einstein
Levitodynamics
Effet tunnel