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Copyright by Kirsten Viering 2006 - Raizen Lab - The University of ...

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frame is obtained <strong>by</strong> expanding the sum,<br />

T(1, 0) = T ′ (1, 0) cos θ(r) + 1 √ 2 T ′ (1, −1) sin θ(r) e −iφ(r) + 1 √ 2 T ′ (1, 1) sin θ(r) e iφ(r) . (5.41)<br />

This has to be true for all angles θ and φ. By choosing θ = φ = 0 we therefore find that<br />

T(1, 0) = T ′ (1, 0) = β0,0. (5.42)<br />

We will use the Wigner-Eckart <strong>The</strong>orem to determine the remaining effective<br />

Raman-Rabi frequencies in the rotated frame; using eq. A.6 we find them to be<br />

β−1,0 = β1,0 = 1<br />

2 β0,0. (5.43)<br />

After doing the transformation to the lab frame using eq. 5.41 the Raman-Rabi fre-<br />

quency become<br />

β0,0(r) = T ′ (1, 0) cos θ(r) = β0,0 cos θ(r) (5.44)<br />

β−1,0(r) = 1 √ 2 T ′ (1, −1) sin θ(r) = 1<br />

β1,0(r) = 1 √ 2 T ′ (1, 1) sin θ(r) = 1<br />

2 √ 2 β0,0 sin θ(r) (5.45)<br />

2 √ 2 β0,0 sin θ(r). (5.46)<br />

We have neglected phase information in these expressions since only the magnitude<br />

<strong>of</strong> the Raman-Rabi frequencies matters for the final state probability. <strong>The</strong> remaining<br />

Raman-Rabi frequencies <strong>of</strong> the initial states with magnetic quantum number m = ±1<br />

can be treated similarly.<br />

<strong>The</strong> final state probability can therefore be determined <strong>by</strong> adding the contribu-<br />

tions from all initially populated states. <strong>The</strong> transfer efficiency is determined <strong>by</strong> the<br />

product <strong>of</strong> the effective Raman-Rabi frequency and the pulse duration, while the prod-<br />

uct <strong>of</strong> the detuning from resonance due to a magnetic field gradient and the pulse dura-<br />

tion determines the resolution. <strong>The</strong> magnitude <strong>of</strong> the external magnetic field influences<br />

the effective detuning (δ − δB(r)), while the direction affects the effective Raman-Rabi<br />

i<br />

frequency β.<br />

39

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