21 research outputs found
Fermi Condensates
Ultracold atomic gases have proven to be remarkable model systems for
exploring quantum mechanical phenomena. Experimental work on gases of fermionic
atoms in particular has seen large recent progress including the attainment of
so-called Fermi condensates. In this article we will discuss this recent
development and the unique control over interparticle interactions that made it
possible.Comment: Proceedings of ICAP-2004 (Rio de Janeiro). Review of Potassium
experiment at JILA, Boulder, C
Cooling a single atom in an optical tweezer to its quantum ground state
We report cooling of a single neutral atom to its three-dimensional
vibrational ground state in an optical tweezer. After employing Raman sideband
cooling for tens of milliseconds, we measure via sideband spectroscopy a
three-dimensional ground-state occupation of ~90%. We further observe coherent
control of the spin and motional state of the trapped atom. Our demonstration
shows that an optical tweezer, formed simply by a tightly focused beam of
light, creates sufficient confinement for efficient sideband cooling. This
source of ground-state neutral atoms will be instrumental in numerous quantum
simulation and logic applications that require a versatile platform for storing
and manipulating ultracold single neutral atoms. For example, these results
will improve current optical tweezer experiments studying atom-photon coupling
and Rydberg quantum logic gates, and could provide new opportunities such as
rapid production of single dipolar molecules or quantum simulation in tweezer
arrays.Comment: Updated intro, titl
Population mixing due to dipole-dipole interactions in a 1D array of multilevel atoms
We examine theoretically how dipole-dipole interactions arising from multiple
photon scattering lead to a modified distribution of ground state populations
in a driven, ordered 1D array of multilevel atoms. Specifically, we devise a
level configuration in which a ground-state population accumulated due solely
to dipole-dipole interactions can be up to 20\% in regimes accessible to
current experiments with neutral atom arrays. For much larger systems, the
steady state can consist of an equal distribution of population across the
ground state manifold. Our results illustrate how dipole-dipole interactions
can be accentuated through interference, and regulated by the geometry of
ordered atom arrays. More generally, control techniques for multilevel atoms
that can be degraded by multiple scattering, such as optical pumping, will
benefit from an improved understanding and control of dipole-dipole
interactions available in ordered arrays.Comment: paper is now identical to published versio
Quantum control of continuous systems via nonharmonic potential modulation
We present a theoretical proposal for preparing and manipulating a state of a
single continuous-variable degree of freedom confined to a nonharmonic
potential. By utilizing optimally controlled modulation of the potential's
position and depth, we demonstrate the generation of non-Gaussian states,
including Fock, Gottesman-Kitaev-Preskill, multi-legged-cat, and cubic-phase
states, as well as the implementation of arbitrary unitaries within a selected
two-level subspace. Additionally, we propose protocols for single-shot
orthogonal state discrimination and algorithmic cooling and analyze the
robustness of this control scheme against noise. Since all the presented
protocols rely solely on the precise modulation of the effective nonharmonic
potential landscape, they are relevant to several experiments with
continuous-variable systems, including the motion of a single particle in an
optical tweezer or lattice, or current in circuit quantum electrodynamics.Comment: 7+9 pages, 4+22 figure
Correcting heading errors in optically pumped magnetometers through microwave interrogation
We demonstrate how to measure in-situ for heading errors of optically pumped
magnetometers in geomagnetic fields. For this, we implement microwave-driven
Rabi oscillations and Ramsey interferometry on hyperfine transitions as two
independent methods to detect scalar systematics of free induction decay (FID)
signals. We showcase the wide applicability of this technique by operating in
the challenging parameter regime of compact vapor cells with imperfect pumping
and high buffer gas pressure. In this system, we achieve suppression of large
inaccuracies arising from nonlinear Zeeman (NLZ) shifts by up to a factor of 10
to levels below 0.6 nT. In the Ramsey method we accomplish this, even in
arbitrary magnetic field directions, by employing a hyper-Ramsey protocol and
optical pumping with adiabatic power ramps. For the Rabi technique, this level
of accuracy is reached, despite associated drive-dependent shifts, by
referencing Rabi frequency measurements to a complete atom-microwave coupling
model that incorporates the microwave polarization structure.Comment: 6 pages, 4 figures + supplementary 16 pages, 10 figure