19 research outputs found
Topological lattice using multi-frequency radiation
We describe a novel technique for creating an artificial magnetic field for
ultra-cold atoms using a periodically pulsed pair of counter propagating Raman
lasers that drive transitions between a pair of internal atomic spin states: a
multi-frequency coupling term. In conjunction with a magnetic field gradient,
this dynamically generates a rectangular lattice with a non-staggered magnetic
flux. For a wide range of parameters, the resulting Bloch bands have
non-trivial topology, reminiscent of Landau levels, as quantified by their
Chern numbers.Comment: Replaced with a revised version, 15 pages, 6 figure
Simulating an interacting gauge theory with ultracold Bose gases
We show how density dependent gauge potentials can be induced in dilute gases
of ultracold atoms using light-matter interactions. We study the effect of the
resulting interacting gauge theory and show how it gives rise to novel
topological states in the ultracold gas. We find in particular that the onset
of persistent currents in a ring geometry is governed by a critical number of
particles. The density-dependent gauge potential is also found to support
chiral solitons in a quasi-one-dimensional ultracold Bose gas.Comment: General improvements. Published version: Phys. Rev. Lett. 110, 085301
(2013
Ultraprecise Rydberg atomic localization using optical vortices
We propose a robust localization of the highly-excited Rydberg atoms,
interacting with doughnut-shaped optical vortices. Compared with the earlier
standing-wave (SW)-based localization methods, a vortex beam can provide an
ultrahigh-precision two-dimensional localization solely in the zero-intensity
center, within a confined excitation region down to the nanometer scale. We
show that the presence of the Rydberg-Rydberg interaction permits
counter-intuitively much stronger confinement towards a high spatial resolution
when it is partially compensated by a suitable detuning. In addition, applying
an auxiliary SW modulation to the two-photon detuning allows a
three-dimensional confinement of Rydberg atoms. In this case, the vortex field
provides a transverse confinement while the SW modulation of the two-photon
detuning localizes the Rydberg atoms longitudinally. To develop a new
subwavelength localization technique, our results pave one-step closer to
reduce excitation volumes to the level of a few nanometers, representing a
feasible implementation for the future experimental applications.Comment: oe in pres
From the Jaynes-Cummings model to non-Abelian gauge theories: a guided tour for the quantum engineer
The design of quantum many body systems, which have to fulfill an extensive
number of constraints, appears as a formidable challenge within the field of
quantum simulation. Lattice gauge theories are a particular important class of
quantum systems with an extensive number of local constraints and play a
central role in high energy physics, condensed matter and quantum information.
Whereas recent experimental progress points towards the feasibility of
large-scale quantum simulation of Abelian gauge theories, the quantum
simulation of non-Abelian gauge theories appears still elusive. In this paper
we present minimal non-Abelian lattice gauge theories, whereby we introduce the
necessary formalism in well-known Abelian gauge theories, such as the
Jaynes-Cumming model. In particular, we show that certain minimal non-Abelian
lattice gauge theories can be mapped to three or four level systems, for which
the design of a quantum simulator is standard with current technologies.
Further we give an upper bound for the Hilbert space dimension of a one
dimensional SU(2) lattice gauge theory, and argue that the implementation with
current digital quantum computer appears feasible