698 research outputs found
Theoretical study of a cold atom beam splitter
A theoretical model is presented for the study of the dynamics of a cold
atomic cloud falling in the gravity field in the presence of two crossing
dipole guides. The cloud is split between the two branches of this laser guide,
and we compare experimental measurements of the splitting efficiency with
semiclassical simulations. We then explore the possibilities of optimization of
this beam splitter. Our numerical study also gives access to detailed
information, such as the atom temperature after the splitting
Quantum-enhanced gyroscopy with rotating anisotropic Bose–Einstein condensates
High-precision gyroscopes are a key component of inertial navigation systems. By considering matter wave gyroscopes that make use of entanglement it should be possible to gain some advantages in terms of sensitivity, size, and resources used over unentangled optical systems. In this paper we consider the details of such a quantum-enhanced atom interferometry scheme based on atoms trapped in a carefully-chosen rotating trap. We consider all the steps: entanglement generation, phase imprinting, and read-out of the signal and show that quantum enhancement should be possible in principle. While the improvement in performance over equivalent unentangled schemes is small, our feasibility study opens the door to further developments and improvements
Propagation of Bose-Einstein condensates in a magnetic waveguide
Gaseous Bose-Einstein condensates of 2-3 million atoms were loaded into a
microfabricated magnetic trap using optical tweezers. Subsequently, the
condensates were released into a magnetic waveguide and propagated 12 mm.
Single-mode propagation was observed along homogeneous segments of the
waveguide. Inhomogeneities in the guiding potential arose from geometric
deformations of the microfabricated wires and caused strong transverse
excitations. Such deformations may restrict the waveguide physics that can be
explored with propagating condensates.Comment: 5 pages, 4 figure
Teaching physics with 670 nm diode lasers—construction of stabilized lasers and lithium cells
We describe the construction and operation of stabilized 670 nm diode lasers for use in undergraduate teaching labs. Because they emit low‐power visible radiation, 670 nm lasers are safe and aesthetically pleasing, and thus are an attractive alternative to near‐infrared diode lasers in the undergraduate laboratory. We also describe the fabrication of a robust and reliable lithium atomic vapor cell, which can be used with the 670 nm diode lasers to perform a variety of atomic physics experiments
Transport of Bose-Einstein Condensates with Optical Tweezers
We have transported gaseous Bose-Einstein condensates over distances up to 44
cm. This was accomplished by trapping the condensate in the focus of an
infrared laser and translating the location of the laser focus with controlled
acceleration. Condensates of order 1 million atoms were moved into an auxiliary
chamber and loaded into a magnetic trap formed by a Z-shaped wire. This
transport technique avoids the optical and mechanical access constraints of
conventional condensate experiments and creates many new scientific
opportunities.Comment: 5 pages, 3 figure
Sensitive gravity-gradiometry with atom interferometry: progress towards an improved determination of the gravitational constant
We here present a high sensitivity gravity-gradiometer based on atom
interferometry. In our apparatus, two clouds of laser-cooled rubidium atoms are
launched in fountain configuration and interrogated by a Raman interferometry
sequence to probe the gradient of gravity field. We recently implemented a
high-flux atomic source and a newly designed Raman lasers system in the
instrument set-up. We discuss the applications towards a precise determination
of the Newtonian gravitational constant G. The long-term stability of the
instrument and the signal-to-noise ratio demonstrated here open interesting
perspectives for pushing the measurement precision below the 100 ppm level
Multi Mode Interferometer for Guided Matter Waves
We describe the fundamental features of an interferometer for guided matter
waves based on Y-beam splitters and show that, in a quasi two-dimensional
regime, such a device exhibits high contrast fringes even in a multi mode
regime and fed from a thermal source.Comment: Final version (accepted to PRL
- …