40 research outputs found
The atomic Bose gas in Flatland
We describe a recent experiment performed with rubidium atoms (Rb),
aiming at studying the coherence properties of a two-dimensional gas of bosonic
particles at low temperature. We have observed in particular a
Berezinskii--Kosterlitz--Thouless (BKT) type crossover in the system, using a
matter wave heterodyning technique. At low temperatures, the gas is
quasi-coherent on the length scale set by the system size. As the temperature
is increased, the loss of long-range coherence coincides with the onset of the
proliferation of free vortices, in agreement with the microscopic BKT theory.Comment: To appear in "ATOMIC PHYSICS 20" Proceedings of the XX International
Conference on Atomic Physics (ICAP
Loading and cooling in an optical trap via hyperfine dark states
We present an optical cooling scheme that relies on hyperfine dark states to enhance loading and cooling atoms inside deep optical dipole traps. We demonstrate a sevenfold increase in the number of atoms loaded in the conservative potential with strongly shifted excited states. In addition, we use the energy selective dark state to efficiently cool the atoms trapped inside the conservative potential rapidly and without losses. Our findings open the door to optically assisted cooling of trapped atoms and molecules which lack the closed cycling transitions normally needed to achieve low temperatures and the high initial densities required for evaporative cooling
CARIOQA: Definition of a Quantum Pathfinder Mission
A strong potential gain for space applications is expected from the
anticipated performances of inertial sensors based on cold atom interferometry
(CAI) that measure the acceleration of freely falling independent atoms by
manipulating them with laser light. In this context, CNES and its partners
initiated a phase 0 study, called CARIOQA, in order to develop a Quantum
Pathfinder Mission unlocking key features of atom interferometry for space and
paving the way for future ambitious space missions utilizing this technology.
As a cornerstone for the implementation of quantum sensors in space, the
CARIOQA phase 0 aimed at defining the Quantum Pathfinder Mission's scenario and
associated performance objectives. To comply with these objectives, the payload
architecture has been designed to achieve long interrogation time and active
rotation compensation on a BEC-based atom interferometer. A study of the
satellite architecture, including all the subsystems, has been conducted.
Several technical solutions for propulsion and attitude control have been
investigated in order to guarantee optimal operating conditions (limitation of
micro-vibrations, maximization of measurement time). A preliminary design of
the satellite platform was performed.Comment: Proceedings of International Conference on Space Optics (ICSO) 2022;
3-7 October 2022; Dubrovnik; Croati
Dual-wavelength laser source for onboard atom interferometry
We present a compact and stable dual-wavelength laser source for onboard atom
interferometry with two different atomic species. It is based on
frequency-doubled telecom lasers locked on a femtosecond optical frequency
comb. We take advantage of the maturity of fiber telecom technology to reduce
the number of free-space optical components which are intrinsically less
stable, and to make the setup immune to vibrations and thermal fluctuations.
The source provides the frequency agility and phase stability required for atom
interferometry and can easily be adapted to other cold atom experiments. We
have shown its robustness by achieving the first dual-species K-Rb magneto
optical trap in microgravity during parabolic flights
AEDGE: Atomic Experiment for Dark Matter and Gravity Exploration in Space
We propose in this White Paper a concept for a space experiment using cold
atoms to search for ultra-light dark matter, and to detect gravitational waves
in the frequency range between the most sensitive ranges of LISA and the
terrestrial LIGO/Virgo/KAGRA/INDIGO experiments. This interdisciplinary
experiment, called Atomic Experiment for Dark Matter and Gravity Exploration
(AEDGE), will also complement other planned searches for dark matter, and
exploit synergies with other gravitational wave detectors. We give examples of
the extended range of sensitivity to ultra-light dark matter offered by AEDGE,
and how its gravitational-wave measurements could explore the assembly of
super-massive black holes, first-order phase transitions in the early universe
and cosmic strings. AEDGE will be based upon technologies now being developed
for terrestrial experiments using cold atoms, and will benefit from the space
experience obtained with, e.g., LISA and cold atom experiments in microgravity.
This paper is based on a submission (v1) in response to the Call for White
Papers for the Voyage 2050 long-term plan in the ESA Science Programme. ESA
limited the number of White Paper authors to 30. However, in this version (v2)
we have welcomed as supporting authors participants in the Workshop on Atomic
Experiments for Dark Matter and Gravity Exploration held at CERN: ({\tt
https://indico.cern.ch/event/830432/}), as well as other interested scientists,
and have incorporated additional material
Cold atoms in space: community workshop summary and proposed road-map
We summarise the discussions at a virtual Community Workshop on Cold Atoms in Space concerning the status of cold atom technologies, the prospective scientific and societal opportunities offered by their deployment in space, and the developments needed before cold atoms could be operated in space. The cold atom technologies discussed include atomic clocks, quantum gravimeters and accelerometers, and atom interferometers. Prospective applications include metrology, geodesy and measurement of terrestrial mass change due to, e.g., climate change, and fundamental science experiments such as tests of the equivalence principle, searches for dark matter, measurements of gravitational waves and tests of quantum mechanics. We review the current status of cold atom technologies and outline the requirements for their space qualification, including the development paths and the corresponding technical milestones, and identifying possible pathfinder missions to pave the way for missions to exploit the full potential of cold atoms in space. Finally, we present a first draft of a possible road-map for achieving these goals, that we propose for discussion by the interested cold atom, Earth Observation, fundamental physics and other prospective scientific user communities, together with the European Space Agency (ESA) and national space and research funding agencies
Generation of high-purity low-temperature samples of K 39 for applications in metrology
We present an all optical technique to prepare a sample of K in a
magnetically-insensitive state with 95\% purity while maintaining a temperature
of 6 K. This versatile preparation scheme is particularly well suited to
performing matter-wave interferometry with species exhibiting closely-separated
hyperfine levels, such as the isotopes of lithium and potassium, and opens new
possibilities for metrology with these atoms. We demonstrate the feasibility of
such measurements by realizing an atomic gravimeter and a Ramsey-type
spectrometer, both of which exhibit a state-of-the-art sensitivity for cold
potassium.Comment: 6 pages + references, 4 figures, accepted for publication in PR