Title: Optical Atomic Clocks Speaker: Patrick Gill National Physical Laboratory, UK Time: Friday, February 10th, 11.15 Place: Phys. Aud. Abstract: Optical atomic clocks based on laser-cooled single ions have undergone significant development over the last five years, as has been suitably demonstrated by the leading results for the Al+ quantum logic clock, where a frequency inaccuracy below 10^-17 has recently been reported [1]. A number of optical clock systems now achieve or exceed the performance of the Cs fountain primary standards used to realise the SI second. At NPL, we are researching single trapped ion and neutral atom optical lattice systems as future optical frequency standards and clocks, within the context of a possible redefinition of the second at the end of the decade. These include the single 88Sr+ ion 2S1/2 - 2D 5/2 quadrupole clock transition at 674 nm, and the octupole / quadrupole (467 nm / 435 nm) double clock system in 171Yb+, as well as the Sr neutral optical lattice clock at 698 nm. I will discuss aspects of these experiments. I will also discuss our development of monolithic ion microtraps built into silicon wafers. These have potential as platforms for miniature ion clocks with multiple ions, quantum logic clocks and space clocks. With the high level of accuracy now on offer from a number of optical clock systems, the need for remote clock comparisons at a level that does not compromise their operating capability becomes paramount. I will point to some recent remote clock comparison experiments at NPL. Finally, the exquisite sensitivity of optical clocks points to their use as highly sensitive probes for tests of physics and fundamental constants. A natural extension to this application might be their deployment in future fundamental tests in space, where seismic noise is reduced and larger gravitational changes are possible. [1] C.-W. Chou, D.B. Hume, J.C.J. Koelemeij, D.J. Wineland and T. Rosenband Frequency Comparison of Two High-Accuracy Al+ Optical Clocks Phys. Rev. Lett. 104, 070802 (2010) Jacob Sherson and Aurélien Dantan Coffee, tea and cake will be served at 11.05 ----------------------------------- Aurelien Dantan Ion Trap Group Department of Physics and Astronomy University of Aarhus Ny Munkegade, bygn. 1520 8000 Aarhus Denmark +4589423602