1,644 research outputs found
Amplifying single impurities immersed in a gas of ultra cold atoms
We present a method for amplifying a single or scattered impurities immersed
in a background gas of ultra cold atoms so that they can be optically imaged
and spatially resolved. Our approach relies on a Raman transfer between two
stable atomic hyperfine states that is conditioned on the presence of an
impurity atom. The amplification is based on the strong interaction among atoms
excited to Rydberg states. We perform a detailed analytical study of the
performance of the proposed scheme with particular emphasis on the influence of
many-body effects.Comment: 5 pages, 4 figure
A Berger type normal holonomy theorem for complex submanifolds
We prove a kind of Berger-Simons' Theorem for the normal holonomy group of a complex submanifold of the projective spac
Fermionic collective excitations in a lattice gas of Rydberg atoms
We investigate the many-body quantum states of a laser-driven gas of Rydberg
atoms confined to a large spacing ring lattice. If the laser driving is much
stronger than the van-der-Waals interaction among the Rydberg sates, these
many-body states are collective fermionic excitations. The first excited state
is a spin-wave that extends over the entire lattice. We demonstrate that our
system permits to study fermions in the presence of disorder although no
external atomic motion takes place. We analyze how this disorder influences the
excitation properties of the fermionic states. Our work shows a route towards
the creation of complex many-particle states with atoms in lattices
Creating collective many-body states with highly excited atoms
We study the collective excitation of a gas of highly excited atoms confined
to a large spacing ring lattice, where the ground and the excited states are
coupled resonantly via a laser field. Our attention is focused on the regime
where the interaction between the highly excited atoms is very weak in
comparison to the Rabi frequency of the laser. We demonstrate that in this case
the many-body excitations of the system can be expressed in terms of free
spinless fermions. The complex many-particle states arising in this regime are
characterized and their properties, e.g. their correlation functions, are
studied. In addition we investigate how one can actually experimentally access
some of these many-particle states by a temporal variation of the laser
parameters.Comment: 10 pages, 7 figure
Creation of collective many-body states and single photons from two-dimensional Rydberg lattice gases
The creation of collective many-body quantum states from a two-dimensional
lattice gas of atoms is studied. Our approach relies on the van-der-Waals
interaction that is present between alkali metal atoms when laser excited to
high-lying Rydberg s-states. We focus on a regime in which the laser driving is
strong compared to the interaction between Rydberg atoms. Here energetically
low-lying many-particle states can be calculated approximately from a quadratic
Hamiltonian. The potential usefulness of these states as a resource for the
creation of deterministic single-photon sources is illustrated. The properties
of these photon states are determined from the interplay between the particular
geometry of the lattice and the interatomic spacing.Comment: 12 pages, 8 figure
Long-range interacting many-body systems with alkaline-earth-metal atoms
Alkaline-earth-metal atoms exhibit long-range dipolar interactions, which are
generated via the coherent exchange of photons on the 3P_0-3D_1-transition of
the triplet manifold. In case of bosonic strontium, which we discuss here, this
transition has a wavelength of 2.7 \mu m and a dipole moment of 2.46 Debye, and
there exists a magic wavelength permitting the creation of optical lattices
that are identical for the states 3P_0 and 3D_1. This interaction enables the
realization and study of mixtures of hard-core lattice bosons featuring
long-range hopping, with tuneable disorder and anisotropy. We derive the
many-body Master equation, investigate the dynamics of excitation transport and
analyze spectroscopic signatures stemming from coherent long-range interactions
and collective dissipation. Our results show that lattice gases of
alkaline-earth-metal atoms permit the creation of long-lived collective atomic
states and constitute a simple and versatile platform for the exploration of
many-body systems with long-range interactions. As such, they represent an
alternative to current related efforts employing Rydberg gases, atoms with
large magnetic moment, or polar molecules
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