27 research outputs found
Realization of a superconducting atom chip
We have trapped rubidium atoms in the magnetic field produced by a
superconducting atom chip operated at liquid Helium temperatures. Up to
atoms are held in a Ioffe-Pritchard trap at a distance of 440
m from the chip surface, with a temperature of 40 K. The trap
lifetime reaches 115 s at low atomic densities. These results open the way to
the exploration of atom--surface interactions and coherent atomic transport in
a superconducting environment, whose properties are radically different from
normal metals at room temperature.Comment: Submitted to Phys. Rev. Let
Bose-Einstein condensation on a superconducting atom chip
We have produced a Bose-Einstein condensate (BEC) on an atom chip using only
superconducting wires in a cryogenic environment. We observe the onset of
condensation for 10^4 atoms at a temperature of 100 nK. This result opens the
way for studies of atom losses and decoherence in a BEC interacting with a
superconducting surface. Studies of dipole-blockade with long-lived Rydberg
atoms in a small and dense atomic sample are underway.Comment: 4 pages, 4 figures. Accepted for publication in Europhysics Letter
Inductively guided circuits for ultracold dressed atoms
Recent progress in optics, atomic physics and material science has paved the way to study quantum effects in ultracold atomic alkali gases confined to non-trivial geometries. Multiply connected traps for cold atoms can be prepared by combining inhomogeneous distributions of DC and radio-frequency electromagnetic fields with optical fields that require complex systems for frequency control and stabilization. Here we propose a flexible and robust scheme that creates closed quasi-one-dimensional guides for ultracold atoms through the âdressingâ of hyperfine sublevels of the atomic ground state, where the dressing field is spatially modulated by inductive effects over a micro-engineered conducting loop. Remarkably, for commonly used atomic species (for example, 7Li and 87Rb), the guide operation relies entirely on controlling static and low-frequency fields in the regimes of radio-frequency and microwave frequencies. This novel trapping scheme can be implemented with current technology for micro-fabrication and electronic control
Trapped electron coupled to superconducting devices
We propose to couple a trapped single electron to superconducting structures
located at a variable distance from the electron. The electron is captured in a
cryogenic Penning trap using electric fields and a static magnetic field in the
Tesla range. Measurements on the electron will allow investigating the
properties of the superconductor such as vortex structure, damping and
decoherence. We propose to couple a superconducting microwave resonator to the
electron in order to realize a circuit QED-like experiment, as well as to
couple superconducting Josephson junctions or superconducting quantum
interferometers (SQUIDs) to the electron. The electron may also be coupled to a
vortex which is situated in a double well potential, realized by nearby pinning
centers in the superconductor, acting as a quantum mechanical two level system
that can be controlled by a transport current tilting the double well
potential. When the vortex is trapped in the interferometer arms of a SQUID,
this would allow its detection both by the SQUID and by the electron.Comment: 13 pages, 5 figure
Thermal properties of AlN-based atom chips
We have studied the thermal properties of atom chips consisting o high
thermal conductivity Aluminum Nitride (AlN) substrates on which gold microwires
are directly deposited. We have measured the heating of wires of several widths
and with different thermal couplings to the copper mount holding the chip. The
results are in good agreement with a theoretical model where the copper mount
is treated as a heat sink and the thermal interface resistance between the wire
and the substrate is vanishing. We give analytical formulas describing the
different transient heating regimes and the steady state. We identify criteria
to optimize the design of a chip as well as the maximal currents that can
be fed in the wires. For a 600 m thick-chip glued on a copper block with
Epotek H77, we find A for a 3 m high, 200 m wide-wire