TY  - JOUR
A1  - Japha, Yonathan
A1  - Zhou, Shuyu
A1  - Keil, Mark
A1  - Folman, Ron
A1  - Henkel, Carsten
A1  - Vardi, Amichay
T1  - Suppression and enhancement of decoherence in an atomic Josephson junction
JF  - NEW JOURNAL OF PHYSICS
N2  - We investigate the role of interatomic interactions when a Bose gas, in a double-well potential with a finite tunneling probability (a 'Bose–Josephson junction'), is exposed to external noise. We examine the rate of decoherence of a system initially in its ground state with equal probability amplitudes in both sites. The noise may induce two kinds of effects: firstly, random shifts in the relative phase or number difference between the two wells and secondly, loss of atoms from the trap. The effects of induced phase fluctuations are mitigated by atom–atom interactions and tunneling, such that the dephasing rate may be suppressed by half its single-atom value. Random fluctuations may also be induced in the population difference between the wells, in which case atom–atom interactions considerably enhance the decoherence rate. A similar scenario is predicted for the case of atom loss, even if the loss rates from the two sites are equal. We find that if the initial state is number-squeezed due to interactions, then the loss process induces population fluctuations that reduce the coherence across the junction. We examine the parameters relevant for these effects in a typical atom chip device, using a simple model of the trapping potential, experimental data, and the theory of magnetic field fluctuations near metallic conductors. These results provide a framework for mapping the dynamical range of barriers engineered for specific applications and set the stage for more complex atom circuits ('atomtronics').
KW  - atomtronics
KW  - coherence
KW  - ultracold atoms
KW  - Bose-Einstein condensate
KW  - Bose-Hubbard model
KW  - tunneling
KW  - Josephson junction
Y1  - 2016
U6  - https://doi.org/10.1088/1367-2630/18/5/055008
SN  - 1367-2630
VL  - 18
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Henkel, Carsten
A1  - Jacob, Georg
A1  - Stopp, Felix
A1  - Schmidt-Kaler, Ferdinand
A1  - Keil, Mark
A1  - Japha, Yonathan
A1  - Folman, Ron
T1  - Stern-Gerlach splitting of low-energy ion beams
JF  - New journal of physics : the open-access journal for physics
N2  - We present a feasibility study with several magnetic field configurations for creating spin-dependent forces that can split a low-energy ion beam by the Stern-Gerlach (SG) effect. To the best of our knowledge, coherent spin-splittings of charged particles have yet to be realised. Our proposal is based on ion source parameters taken from a recent experiment that demonstrated single-ion implantation from a high-brightness ion source combined with a radio-frequency Paul trap. The inhomogeneous magnetic fields can be created by permanently magnetised microstructures or from current-carrying wires with sizes in the micron range, such as those recently used in a successful implementation of the SG effect with neutral atoms. All relevant forces (Lorentz force and image charges) are taken into account, and measurable splittings are found by analytical and numerical calculations.
KW  - spin-dependent forces
KW  - Stern-Gerlach effect
KW  - ion optics
KW  - beam splitter
KW  - magnetic microstructures
Y1  - 2019
U6  - https://doi.org/10.1088/1367-2630/ab36c7
SN  - 1367-2630
VL  - 21
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Dikovsky, Valery
A1  - Sokolovsky, Vladimir
A1  - Zhang, Bin
A1  - Henkel, Carsten
A1  - Folman, Ron
T1  - Superconducting atom chips : advantages and challenges
N2  - Superconductors are considered in view of applications to atom chip devices. The main features of magnetic traps based on superconducting wires in the Meissner and mixed states are discussed. The former state may mainly be interesting for improved atom optics, while in the latter, cold atoms may provide a probe of superconductor phenomena. The properties of a magnetic side guide based on a single superconducting strip wire placed in an external magnetic field are calculated analytically and numerically. In the mixed state of type II superconductors, inhomogeneous trapped magnetic flux, relaxation processes and noise caused by vortex motion are posing specific challenges for atom trapping.
Y1  - 2009
UR  - http://www.springerlink.com/content/101161
U6  - https://doi.org/10.1140/epjd/e2008-00261-5
SN  - 1434-6060
ER  -