München 2004 – scientific programme
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Q: Quantenoptik und Photonik
Q 41: Quanteneffekte III
Q 41.5: Talk
Thursday, March 25, 2004, 17:45–18:00, HS 218
Single atom capturing effect from a single distant mirror — •Alex Wilson, Pavel Bushev, Jürgen Eschner, and Rainer Blatt — Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria
A single, trapped barium ion is seen to experience vacuum field forces due to the presence of a single, plane, mirror some 25 cm away. These forces are associated with a mirror-induced shift of the excited state, which was recently observed using a spectroscopic method to probe the internal state of the ion [1]. This shift is the dispersive counterpart to the modified spontaneous decay rate previously observed [2]. The magnitude of these effects are scaled by the collection efficiency of the lens that collimates light from the 138Ba+ ion onto the retro-reflecting mirror. Scanning the ion-mirror distance leads to a sinusoidally-varying shift of the excited state. The mirror therefore establishes weak trapping and anti-trapping potentials that alter the strong confining potential of the Paul trap. A new technique has enabled the sensitive and rapid measurement of the ion’s 1 MHz oscillation frequency. This trap frequency is seen to vary upon changing the ion-mirror distance. Hence so-called vacuum forces, due to the presence of the mirror, have been observed by measuring the motional (or external) states of the ion. In the strictest sense the effects of the mirror cannot be described by modified vacuum fields alone and the ion’s own radiation reaction field must also be considered to be modified.
[1] M.A. Wilson et al., Phys. Rev. Lett. 91, 213602, (2003)
[2] J. Eschner et al., Nature 413, 495-498, (2001)