22 research outputs found
Squeezing of Atomic Quantum Projection Noise
We provide a framework for understanding recent experiments on squeezing of a
collective atomic pseudo-spin, induced by a homodyne measurement on
off-resonant probe light interrogating the atoms. The detection of light
decimates the atomic state distribution and we discuss the conditions under
which the resulting reduced quantum fluctuations are metrologically relevant.
In particular, we consider a dual probe scheme which benefits from a
cancelation of classical common mode noise sources such that quantum
fluctuations from light and atoms are the main contributions to the detected
signal.Comment: Submitted to Journal of Modern Optic
Quantum phase transition to unconventional multi-orbital superfluidity in optical lattices
Orbital physics plays a significant role for a vast number of important
phenomena in complex condensed matter systems such as high-T
superconductivity and unconventional magnetism. In contrast, phenomena in
superfluids -- especially in ultracold quantum gases -- are commonly well
described by the lowest orbital and a real order parameter. Here, we report on
the observation of a novel multi-orbital superfluid phase with a {\it complex}
order parameter in binary spin mixtures. In this unconventional superfluid, the
local phase angle of the complex order parameter is continuously twisted
between neighboring lattice sites. The nature of this twisted superfluid
quantum phase is an interaction-induced admixture of the p-orbital favored by
the graphene-like band structure of the hexagonal optical lattice used in the
experiment. We observe a second-order quantum phase transition between the
normal superfluid (NSF) and the twisted superfluid phase (TSF) which is
accompanied by a symmetry breaking in momentum space. The experimental results
are consistent with calculated phase diagrams and reveal fundamentally new
aspects of orbital superfluidity in quantum gas mixtures. Our studies might
bridge the gap between conventional superfluidity and complex phenomena of
orbital physics.Comment: 5 pages, 4 figure
Space-borne Bose-Einstein condensation for precision interferometry
Space offers virtually unlimited free-fall in gravity. Bose-Einstein
condensation (BEC) enables ineffable low kinetic energies corresponding to
pico- or even femtokelvins. The combination of both features makes atom
interferometers with unprecedented sensitivity for inertial forces possible and
opens a new era for quantum gas experiments. On January 23, 2017, we created
Bose-Einstein condensates in space on the sounding rocket mission MAIUS-1 and
conducted 110 experiments central to matter-wave interferometry. In particular,
we have explored laser cooling and trapping in the presence of large
accelerations as experienced during launch, and have studied the evolution,
manipulation and interferometry employing Bragg scattering of BECs during the
six-minute space flight. In this letter, we focus on the phase transition and
the collective dynamics of BECs, whose impact is magnified by the extended
free-fall time. Our experiments demonstrate a high reproducibility of the
manipulation of BECs on the atom chip reflecting the exquisite control features
and the robustness of our experiment. These properties are crucial to novel
protocols for creating quantum matter with designed collective excitations at
the lowest kinetic energy scales close to femtokelvins.Comment: 6 pages, 4 figure
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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
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
The Bose-Einstein Condensate and Cold Atom Laboratory
Microgravity eases several constraints limiting experiments with ultracold andcondensed atoms on ground. It enables extended times of flight withoutsuspension and eliminates the gravitational sag for trapped atoms. Theseadvantages motivated numerous initiatives to adapt and operate experimentalsetups on microgravity platforms. We describe the design of the payload,motivations for design choices, and capabilities of the Bose-Einstein Condensateand Cold Atom Laboratory (BECCAL), a NASA-DLR collaboration. BECCALbuilds on the heritage of previous devices operated in microgravity, featuresrubidium and potassium, multiple options for magnetic and optical trapping,different methods for coherent manipulation, and will offer new perspectives forexperiments on quantum optics, atom optics, and atom interferometry in theunique microgravity environment on board the International Space Station
AEDGE: Atomic Experiment for Dark Matter and Gravity Exploration in Space
Abstract: 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. KCL-PH-TH/2019-65, CERN-TH-2019-12