165 research outputs found
Three level atom optics in dipole traps and waveguides
An analogy is explored between a setup of three atomic traps coupled via
tunneling and an internal atomic three-level system interacting with two laser
fields. Within this scenario we describe a STIRAP like process which allows to
move an atom between the ground states of two trapping potentials and analyze
its robustness. This analogy is extended to other robust and coherent transport
schemes and to systems of more than a single atom. Finally it is applied to
manipulate external degrees of freedom of atomic wave packets propagating in
waveguides.Comment: 14 pages, 6 figures; submitted to special issue 'Quantum Control of
Light and Matter' of Optics Communication
Double barrier potentials for matter-wave gap solitons
We investigate collisions of solitons of the gap type, supported by a lattice
potential in repulsive Bose-Einstein condensates, with an effective
double-barrier potential that resembles a Fabry-Perot cavity. We identify
conditions under which the trapping of the entire incident soliton in the
cavity is possible. Collisions of the incident soliton with an earlier trapped
one are considered too. In the latter case, many outcomes of the collisions are
identified, including merging, release of the trapped soliton with or without
being replaced by the incoming one, and trapping of both solitons.Comment: 5 pages, 4 figure
Manipulating mesoscopic multipartite entanglement with atom-light interfaces
Entanglement between two macroscopic atomic ensembles induced by measurement
on an ancillary light system has proven to be a powerful method for engineering
quantum memories and quantum state transfer. Here we investigate the
feasibility of such methods for generation, manipulation and detection of
genuine multipartite entanglement between mesoscopic atomic ensembles. Our
results extend in a non trivial way the EPR entanglement between two
macroscopic gas samples reported experimentally in [B. Julsgaard, A. Kozhekin,
and E. Polzik, Nature {\bf 413}, 400 (2001)]. We find that under realistic
conditions, a second orthogonal light pulse interacting with the atomic
samples, can modify and even reverse the entangling action of the first one
leaving the samples in a separable state.Comment: 8 pages, 6 figure
Atom Optics with Microfabricated Optical Elements
We introduce a new direction in the field of atom optics, atom interferometry, and neutral-atom quantum information processing. It is based on the use of microfabricated optical elements. With these elements versatile and integrated atom optical devices can be created in a compact fashion. This approach opens the possibility to scale, parallelize, and miniaturize atom optics for new investigations in fundamental research and application. It will lead to new, compact sources of ultracold atoms, compact sensors based on matter wave interference and new approaches towards quantum computing with neutral atoms. The exploitation of the unique features of the quantum mechanical behavior of matter waves and the capabilities of powerful state-of-the-art micro- and nanofabrication techniques lend this approach a special attraction
Coherence Properties of Guided-Atom Interferometers
We present a detailed investigation of the coherence properties of beam
splitters and Mach-Zehnder interferometers for guided atoms. It is demonstrated
that such a setup permits coherent wave packet splitting and leads to the
appearance of interference fringes. We study single-mode and thermal input
states and show that even for thermal input states interference fringes can be
clearly observed, thus demonstrating the multimode operation and the robustness
of the interferometer.Comment: 4 pages, 4 figure
Coherent manipulation of atomic qubits in optical micropotentials
We experimentally demonstrate the coherent manipulation of atomic states in
far-detuned dipole traps and registers of dipole traps based on two-dimensional
arrays of microlenses. By applying Rabi, Ramsey, and spin-echo techniques, we
systematically investigate the dephasing mechanisms and determine the coherence
time. Simultaneous Ramsey measurements in up to 16 dipole traps are performed
and proves the scalability of our approach. This represents an important step
in the application of scalable registers of atomic qubits for quantum
information processing. In addition, this system can serve as the basis for
novel atomic clocks making use of the parallel operation of a large number of
individual clocks each remaining separately addressable.Comment: to be published in Appl. Phys.
Ground state of a partially melted Wigner molecule
We consider three spinless fermions free to move on 2d square lattice with
periodic boundary conditions and interacting via a U/r Coulomb repulsion. When
the Coulomb energy to kinetic energy ratio r_s is large, a rigid Wigner
molecule is formed. As r_s decreases, we show that melting proceeds via an
intermediate regime where a floppy two particle molecule coexists with a
partially delocalized particle. A simple ansatz is given to describe the ground
state of this mesoscopic solid-liquid regime.Comment: to appear in Europhysics Letter
Experimental access to higher-order Zeeman effects by precision spectroscopy of highly charged ions in a Penning trap
We present an experimental concept and setup for laser-microwave
double-resonance spectroscopy of highly charged ions in a Penning trap. Such
spectroscopy allows a highly precise measurement of the Zeeman splittings of
fine- and hyperfine-structure levels due the magnetic field of the trap. We
have performed detailed calculations of the Zeeman effect in the framework of
quantum electrodynamics of bound states as present in such highly charged ions.
We find that apart from the linear Zeeman effect, second- and third-order
Zeeman effects also contribute to the splittings on a level of 10^-4 and 10^-8,
respectively, and hence are accessible to a determination within the achievable
spectroscopic resolution of the ARTEMIS experiment currently in preparation
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