- Conference date: 16-21 July 2006
- Location: Innsbruck (Austria)
Ultracold atoms and molecules provide ideal stages for precision tests of fundamental physics. With microkelvin neutral strontium atoms confined in an optical lattice, we have achieved a fractional resolution of 4 × 10−15 on the 1 S 0 − 3 P 0 doubly‐forbidden 87Sr clock transition at 698 nm. The overall systematic uncertainty of the clock is evaluated below the 10−15 level. The ultrahigh spectral resolution permits resolving the nuclear spin states of the clock transition at small magnetic fields, leading to measurements of the 3 P 0 magnetic moment and metastable lifetime. In addition, photoassociation spectroscopy performed on the narrow 1 S 0 − 3 P 1 transition of 88Sr shows promise for efficient optical tuning of the ground state scattering length and production of ultracold ground‐state molecules. Lattice‐confined Sr2 molecules are suitable for constraining the time‐variation of electron‐proton mass ratio. In a separate experiment, cold, ground state polar molecules produced from Stark decelerators have enabled an order of magnitude improvement in measurement precision of ground‐state, Λ‐doublet microwave transitions in the OH molecule. Comparing the laboratory results to those from OH megamasers in interstellar space will allow a sensitivity of 10−6 for measuring the potential time variation of the fundamental fine structure constant Δα/α over 1010 years. These results have also led to improved understandings in the molecular structure. The study of the low magnetic field behavior of OH in its 2Π3/2 ro‐vibronic ground state precisely determines a differential Landé g‐factor between opposite parity components of the Λ‐doublet.
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