Pumping dynamics of cold-atom experiments in a single vacuum chamber

A nonlinear analytical model for the pressure dynamics in a vacuum chamber, pumped with a sputter ion pump (SIP), is proposed, discussed and experimentally evaluated. The model describes the physics of the pumping mechanism of SIPs in the context of a cold-atom experiment. By using this model, we fit pump-down curves of our vacuum system to extract the relevant physical parameters characterizing its pressure dynamics. The aim of this investigation is the optimization of cold-atom experiments in terms of reducing the dead time for quantum sensing using atom interferometry. We develop a calibration method to improve the precision in pressure measurements via the ion current in SIPs. Our method is based on a careful analysis of the gas conductance and pumping in order to reliably link the pressure readings at the SIP with the actual pressure in the vacuum (science) chamber. Our results are in agreement with the existence of essentially two pumping regimes determined by the pressure level in the system. In particular, we find our results in agreement with the well-known fact that for a given applied voltage, at low pressures, the discharge current efficiently sputters pumping material from the pump’s electrodes. This process sets the leading pumping mechanism in this limit. At high pressures, the discharge current drops and the pumping is mainly performed by the already sputtered material

Technologies habilitantes pour interféromètres compacts à atomes confinés sur puce

In this project we aim to develop a new generation of high sensitivity compact gyrometers capable of meeting the constraints of metrological applications. These inertial sensors will use guided matter waves on an atomic chip, and will be designed to overcome the main limitations of atomic interferometers with free-falling atoms: the relatively short interrogation time and the quantum projection noise (QPN).Dans ce projet nous visons le développement d’une nouvelle génération de gyromètres compacts de haute sensibilité capables de répondre aux contraintes d’applications métrologiques. Ces capteurs inertiels utiliseront des ondes de matière guidées sur puce à atomes, et ils seront conçus afin de nous affranchir de principales limitations des interféromètres atomiques avec des atomes en chute libre : le temps d’interrogation relativement court et le bruit de projection quantique (BPQ)

Enabling techologies for compact atom chip interferometry

Dans ce projet nous visons le développement d’une nouvelle génération de gyromètres compacts de haute sensibilité capables de répondre aux contraintes d’applications métrologiques. Ces capteurs inertiels utiliseront des ondes de matière guidées sur puce à atomes, et ils seront conçus afin de nous affranchir de principales limitations des interféromètres atomiques avec des atomes en chute libre : le temps d’interrogation relativement court et le bruit de projection quantique (BPQ).In this project we aim to develop a new generation of high sensitivity compact gyrometers capable of meeting the constraints of metrological applications. These inertial sensors will use guided matter waves on an atomic chip, and will be designed to overcome the main limitations of atomic interferometers with free-falling atoms: the relatively short interrogation time and the quantum projection noise (QPN)

Technologies habilitantes pour interféromètres compacts à atomes confinés sur puce

In this project we aim to develop a new generation of high sensitivity compact gyrometers capable of meeting the constraints of metrological applications. These inertial sensors will use guided matter waves on an atomic chip, and will be designed to overcome the main limitations of atomic interferometers with free-falling atoms: the relatively short interrogation time and the quantum projection noise (QPN).Dans ce projet nous visons le développement d’une nouvelle génération de gyromètres compacts de haute sensibilité capables de répondre aux contraintes d’applications métrologiques. Ces capteurs inertiels utiliseront des ondes de matière guidées sur puce à atomes, et ils seront conçus afin de nous affranchir de principales limitations des interféromètres atomiques avec des atomes en chute libre : le temps d’interrogation relativement court et le bruit de projection quantique (BPQ)

Nondestructive microwave detection of a coherent quantum dynamics in cold atoms

International audienceCold atom quantum sensors based on atom interferometry are among the most accurate instruments used in fundamental physics, metrology, and foreseen for autonomous inertial navigation. However, they typically have optically complex, cumbersome, and low-bandwidth atom detection systems, limiting their practical applications. Here, we demonstrate an enabling technology for high-bandwidth, compact, and nondestructive detection of cold atoms, using microwave radiation. We measure the reflected microwave signal to coherently and distinctly detect the population of single quantum states with a bandwidth close to 30 kHz and a design destructivity that we set to 0.04%. We use a horn antenna and free-falling molasses cooled atoms in order to demonstrate the feasibility of this technique in conventional cold atom interferometers. This technology, combined with coplanar waveguides used as microwave sources, provides a basic design building block for detection in future atom chip-based compact quantum inertial sensors

Measuring Correlations from the Collective Spin Fluctuations of a Large Ensemble of Lattice-Trapped Dipolar Spin-3 Atoms

International audienceWe perform collective spin measurements to study the buildup of two-body correlations between ≈104 spin s=3 chromium atoms pinned in a 3D optical lattice. The spins interact via long range and anisotropic dipolar interactions. From the fluctuations of total magnetization, measured at the standard quantum limit, we estimate the dynamical growth of the connected pairwise correlations associated with magnetization. The quantum nature of the correlations is assessed by comparisons with analytical short- and long-time expansions and numerical simulations. Our Letter shows that measuring fluctuations of spin populations for s>1/2 spins provides new ways to characterize correlations in quantum many-body systems