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J. Grond, U. Hohenester, I. Mazets, H.-J. Schmiedmayer:
"Atom interferometry with trapped Bose-Einstein condensates: impact of atom-atom interactions";
New Journal of Physics, 12 (2010), 065036; 1 - 29.

Interferometry with ultracold atoms promises the possibility of
ultraprecise and ultrasensitive measurements in many fields of physics, and is
the basis of our most precise atomic clocks. Key to a high sensitivity is the
possibility to achieve long measurement times and precise readout. Ultracold
atoms can be precisely manipulated at the quantum level and can be held for very
long times in traps; they would therefore be an ideal setting for interferometry.
In this paper, we discuss how the nonlinearities from atom-atom interactions,
on the one hand, allow us to efficiently produce squeezed states for enhanced
readout and, on the other hand, result in phase diffusion that limits the phase
accumulation time. We find that low-dimensional geometries are favorable,
with two-dimensional (2D) settings giving the smallest contribution of phase
diffusion caused by atom-atom interactions. Even for time sequences generated
by optimal control, the achievable minimal detectable interaction energy ΔE^min is of the order of 10−4μ, where μ is the chemical potential of the Bose-Einstein
condensate (BEC) in the trap. From these we have to conclude that for more
precise measurements with atom interferometers, more sophisticated strategies,
or turning off the interaction-induced dephasing during the phase accumulation
stage, will be necessary.
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http://dx.doi.org/10.1088/1367-2630/12/6/065036

http://publik.tuwien.ac.at/files/PubDat_187451.pdf