24.07.2013 Views

Experiments to Control Atom Number and Phase-Space Density in ...

Experiments to Control Atom Number and Phase-Space Density in ...

Experiments to Control Atom Number and Phase-Space Density in ...

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

transitions for the excited state polarizability (data taken from [137]). At wavelengths<br />

where the 2s polarizability matches the 1s polarizability, a magic wavelength exists. In<br />

the range from 400 nm <strong>to</strong> 1 µm <strong>and</strong> above three dist<strong>in</strong>ct magic wavelengths exist. The<br />

broadest of these is located around 512.4 nm.<br />

polarizabilitya.u.<br />

1000<br />

500<br />

0<br />

500<br />

4.10 7<br />

1000<br />

5.10 7<br />

6.10 7<br />

7.10 7<br />

wavelengthm<br />

8.10 7<br />

9.10 7<br />

1.10 6<br />

Figure A.1: Scalar polarizability of the 1s (red) <strong>and</strong> 2s (blue) states of a<strong>to</strong>mic hydrogen,<br />

calculated us<strong>in</strong>g equation A.1.<br />

The method outl<strong>in</strong>ed above is limited <strong>in</strong> precision by the number of states that<br />

are <strong>in</strong>cluded <strong>in</strong> the sum. Fortunately, there are other approaches <strong>to</strong> calculat<strong>in</strong>g the<br />

scalar polarizability of hydrogenic a<strong>to</strong>ms [138, 139]. A closed analytical expression for<br />

the scalar polarizability (<strong>in</strong> a<strong>to</strong>mic units) is given by [138]<br />

α1s(ω) = − 1<br />

2 512ν<br />

−<br />

ω2 m=1<br />

9 1m<br />

(ν2 1m −1) 2 (ν1m +1) 8 (ν1m −2)<br />

<br />

2<br />

ν1m −1<br />

·2F1 4,2−ν1m,3−ν1m;<br />

ν1m +1<br />

α2s(ω) = − 1<br />

−<br />

ω2 <br />

·2F1<br />

2<br />

m=1<br />

2 18 ν 9 2m<br />

(ν 2 2m +2) 7 (ν2m −4) 3<br />

4,2−ν2m,3−ν2m;<br />

176<br />

<br />

2<br />

ν2m −2<br />

,<br />

ν2m +2<br />

(A.3)<br />

(A.4)

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!