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Measuring Polarizability with an Atom Interferometer. Melissa Revelle. Overview. The Importance of Atomic Polarizability Our Interferometer Modeling the Experiment Progress Future. Why Atomic Polarizability?. Relates to Van der Waals forces Black body shifts for atomic clocks - PowerPoint PPT Presentation
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Measuring Polarizability with an Atom Interferometer
Melissa Revelle
Overview
The Importance of Atomic Polarizability
Our Interferometer Modeling the
Experiment Progress Future
Why Atomic Polarizability?
Relates to Van der Waals forces Black body shifts for
atomic clocks Depths of optical
dipole traps for atoms
Precision of αNa = 0.5% Precision of αK = 2%
Ep
E
p p
Using Phase Shift to Find Polarizability
Atom beam Detector
1G
v2
2xE
2G 3G
Using Phase Shift to Find Polarizability
Atom beam Detector
1G
v2
2xE
x
2G 3G
Using Phase Shift to Find Polarizability
Atom beam Detector
1G
v2
2xE
x
2G 3G
Original Data
Atom flux at each grating position is recorded Polarizability relates to this phase shift
Phase Shifts in an Atom Interferometer
From the Schrödinger equation for an atom beam, we get:
The total phase shift becomes:
))((2
)(xUTm
xk
1
)(v2
21 dxxE
The Electric Field Gradient Region
x
y
Atom beams
y
x
z
The Electric Field Gradient Region
x
y
y
x
z
Finding the Equipotential Surfaces and Charge Density For an ideal wire and
an image wire:
22
22
0 )(
)(ln
2 xyd
xydV
o
g
d
y0 R
y
x
z
Atom beams
Creating the Model
Integrate along a path in the x direction to get the phase shift.
L=distance from 1G to gradient region
a=grating period
mam
Lhs 55
v
v))v(cos()v(
v))v(sin()v(arctan
dP
dP
Fitting the Data
The model for the E-field and phase shift is used as a fit function
Distance from Cylinder [mm]
Ph
ase
Sh
ift
[rad
]
Data
Fit Function
Summary
We can precisely measure polarizability using atom interferometry.
The electric field must be accurate.
Velocity distribution is important
Current and Future Progress
Improve precision polarizability of sodium and potassium to better than 1%
Measure the polarizability tensor components of molecules.
1.08.23 Na4.00.43 K
References
A.Salop, E. Pollack, and B. Bederson, Phys. Rev. 124, 1431 (1961)
L. de Broglie, Ann. Phys. (Paris) 3, 22 (1925)
R. Molof, H. Schwartz, T. Miller, and B. Bederson, Phys. Rev. A 10, 1131 (1974)