Download Evaluation of atom-environment interaction based on decoherence

APPC12 B3-PWe-6
The 12th Asia Pacific Physics Conference
Evaluation of atom-environment interaction based on
decoherence of sodium atom interferometry
Keisuke Nakamura and Atsuo Morinaga
Faculty of Science and Technology, Tokyo University of Science,
2641 Yamazaki, Noda-shi, Chiba 278-8510, Japan
[email protected]
Recently, it has been discussed whether one can access the spacetime fluctuation
which comes from quantum gravity through measurement of the decoherence 𝜌 of
atom interferometer (AI). Mang and co-authors derived the following equation
𝜌 = 1⁄3𝜆3 (𝑀⁄𝑀𝑃 )2 (𝑇⁄𝑇𝑃 ) where 𝜆 is a cutoff parameter which defines a scale
ℓ = 𝜆𝐿𝑃 (𝐿𝑃 is Plank length) that the spacetime fluctuation reaches [1-2]. As an
example, they estimated 𝜆 ≥ 1890 using the 𝜌 of the cesium AI experiment [3]. Of
course, the decoherence must be affected due to other atom-environment interactions.
Therefore, it is necessary to remove them in order to evaluate 𝜆 accurately. We
examined several sources of decoherence using the cold sodium AI (Fig. 1). As a
result, we found that main source is a non-uniform magnetic field, and the theoretical
curve (solid curve) based on the width of Rabi spectrum was in good agreement with
the experimental values (Fig. 2).
[1] C. H-T. Wang, et al., Class. Quantum Grav. 23, L59–L65 (2006), [2] P. M.
Bonifacio, et al., Class. Quantum Grav. 26 (2009), [3] A. Peters, et al., Phil. Trans. R.
1.0
0.20
V (T )/V (1)
Population probability
Soc. Lond. A 355, 2223-2233 (1997)
0.15
0.10
0.05
0.00
-1.0
0.0
1.0
2.0
0.8
0.6
0.4
0.0
0
3.0
Experimental values
Theoretical curve
0.2
2
4
6
8
10
12
T [ms]
Detunig frequency [kHz]
Fig. 1. Ramsey fringes of sodium AI.
Fig. 2. Decoherence of sodium AI.
Separetion time T=0.1ms.Visibility V=0.69.
Decoherence 𝜌 = 1 − 𝑉(𝑇)/𝑉(1).
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