37 research outputs found
Controlling and Detecting Spin Correlations of Ultracold Atoms in Optical lattices
We report on the controlled creation of a valence bond state of delocalized
effective-spin singlet and triplet dimers by means of a bichromatic optical
superlattice. We demonstrate a coherent coupling between the singlet and
triplet states and show how the superlattice can be employed to measure the
singlet-fraction employing a spin blockade effect. Our method provides a
reliable way to detect and control nearest-neighbor spin correlations in
many-body systems of ultracold atoms. Being able to measure these correlations
is an important ingredient to study quantum magnetism in optical lattices. We
furthermore employ a SWAP operation between atoms being part of different
triplets, thus effectively increasing their bond-length. Such SWAP operation
provides an important step towards the massively parallel creation of a
multi-particle entangled state in the lattice.Comment: 6 pages, 4 figure
How to estimate the differential acceleration in a two-species atom interferometer to test the equivalence principle
We propose a scheme for testing the weak equivalence principle (Universality
of Free Fall) using an atom-interferometric measurement of the local
differential acceleration between two atomic species with a large mass ratio as
test masses. A apparatus in free fall can be used to track atomic free-fall
trajectories over large distances. We show how the differential acceleration
can be extracted from the interferometric signal using Bayesian statistical
estimation, even in the case of a large mass and laser wavelength difference.
We show that this statistical estimation method does not suffer from
acceleration noise of the platform and does not require repeatable experimental
conditions. We specialize our discussion to a dual potassium/rubidium
interferometer and extend our protocol with other atomic mixtures. Finally, we
discuss the performances of the UFF test developed for the free-fall (0-g)
airplane in the ICE project (\verb"http://www.ice-space.fr"
Quantum Spin Dynamics of Mode-Squeezed Luttinger Liquids in Two-Component Atomic Gases
We report on the observation of the phase dynamics of interacting
one-dimensional ultracold bosonic gases with two internal degrees of freedom.
By controlling the non-linear atomic interactions close to a Feshbach resonance
we are able to induce a phase diffusive many-body spin dynamics. We monitor
this dynamical evolution by Ramsey interferometry, supplemented by a novel,
many-body echo technique. We find that the time evolution of the system is well
described by a Luttinger liquid initially prepared in a multimode squeezed
state. Our approach allows us to probe the non-equilibrium evolution of
one-dimensional many-body quantum systems.Comment: 4 pages, 3 figures Updated version, minor change
Quasicontinuous horizontally guided atom laser: coupling spectrum and flux limits
We study in detail the flux properties of a radiofrequency outcoupled
horizontally guided atom laser, following the scheme demonstrated in [Guerin W
et al. 2006 Phys. Rev. Lett. 97 200402]. Both the outcoupling spectrum (flux of
the atom laser versus rf frequency of the outcoupler) and the flux limitations
imposed to operate in the quasicontinuous regime are investigated. These
aspects are studied using a quasi-1D model, whose predictions are shown to be
in fair agreement with the experimental observations. This work allows us to
identify the operating range of the guided atom laser and to confirm its good
promises in view of studying quantum transport phenomena
Conception et réalisation d'un gravimètre à atomes froids
PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF
Isolated core excitation of high orbital quantum number Rydberg states of ytterbium
We study isolated core excitation of ultra cold ytterbium Rydberg atoms of high orbital quantum number. Measurements were performed on the 6s 1/2 40l → 6p 1/2 40l transition with l = 5−9. The extracted energy shifts and autoionization rates are in good agreement with a model based on independant electrons, taking into account interactions in a perturbative approach. We reveal a particularly long persistence of the autoionization rates with the orbital quantum number, explained by the strong coupling of the 6p 1/2 nl autoionizing state with the 5d 3/2 l continua compared to previously studied divalent atoms
Coherent Light Shift on Alkaline-Earth Rydberg Atoms from Isolated Core Excitation without Autoionization
International audienceNew experimental quantum simulation platforms have recently been implemented with divalent atoms trapped in optical tweezer arrays, with promising performance. The second valence electron also brings about new prospects through the so-called isolated core excitation (ICE). However, autoionization presents a strong limitation to this use. In this study, we propose and demonstrate a new approach to applying a sizable light shift to a Rydberg state with close-to-resonant ICE while avoiding autoionization. In particular, we investigate the ICE of ytterbium atoms in 1S0 Rydberg states. Spectroscopic studies of the induced autoionization and the light shift imparted to the Rydberg states are well accounted for with multichannel quantum defect theory. Such control over the inner electron without disturbing the Rydberg electron brings about a new tool for the targeted coherent manipulation of Rydberg states in quantum simulation or quantum computing experiments performed with alkaline-earth atoms
Measurement of the sensitivity function intime-domain atomic interferometer
International audienc
Measurement of the sensitivity function intime-domain atomic interferometer
International audienc