arXiv subjects

A. Kasper

Publications and source records attributed to A. Kasper.

4 recordsLinked to original sources

arXiv2007

Persistent Supercurrent Atom Chip

Rubidium 87 atoms are trapped in an Ioffe-Pritchard potential generated with a persistent supercurrent that flows in a loop circuit patterned on a sapphire surface. The superconducting circuit is a closed loop made of 100 micro meter wide MBE-grown MgB2 stripe carrying a supercurrent of 2.5 A. To control the supercurrent in the stripe, an on-chip thermal switch operated by a focused argon-ion laser is developed. The switch operates as an on/off switch of the supercurrent, or as a device to set the current to a specific value with the aid of an external magnetic field. The current can be set even without an external source if the change is in decreasing direction.

cond-mat.supr-con↗

arXiv2005

Nanoscale atomic waveguides with suspended carbon nanotubes

We propose an experimentally viable setup for the realization of one-dimensional ultracold atom gases in a nanoscale magnetic waveguide formed by single doubly-clamped suspended carbon nanotubes. We show that all common decoherence and atom loss mechanisms are small guaranteeing a stable operation of the trap. Since the extremely large current densities in carbon nanotubes are spatially homogeneous, our proposed architecture allows to overcome the problem of fragmentation of the atom cloud. Adding a second nanowire allows to create a double-well potential with a moderate tunneling barrier which is desired for tunneling and interference experiments with the advantage of tunneling distances being in the nanometer regime.

quant-ph↗

arXiv2003

Optimized U-MOT for experiments with ultracold atoms near surfaces

We present an integrated wire-based magnetooptical trap for the simplified trapping and cooling of large numbers of neutral atoms near material surfaces. With a modified U-shaped current-carrying Cu structure we collect $>3\times 10^8$ $^{87}$Rb atoms in a mirror MOT without using quadrupole coils. These atoms are subsequently loaded to a Z-wire trap where they are evaporatively cooled to a Bose-Einstein condensate close to the surface.

cond-mat.soft↗

arXiv2002

Bose-Einstein Condensation in a simple Microtrap

A Bose-Einstein condensate is created in a simple and robust miniature Ioffe-Pritchard trap, the so-called Z trap. This trap follows from the mere combination of a Z-shaped current carrying wire and a homogeneous bias field. The experimental procedure allows condensation of typically 3x10^5 Rb-87 atoms in the |F=2, m_F=2> state close to any mirroring surface, irrespective of its structure, thus it is ideally suited as a source for cold atom physics near surfaces.

cond-mat.soft↗