Bulletin of the American Physical Society
41st Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 55, Number 5
Tuesday–Saturday, May 25–29, 2010; Houston, Texas
Session X1: Hot Topics |
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Chair: Chris Monroe, University of Maryland Room: Imperial East |
Saturday, May 29, 2010 10:30AM - 11:00AM |
X1.00001: Trapping ultracold dysprosium: A highly magnetic gas for dipolar physics Invited Speaker: Ultracold dysprosium gases, with a magnetic moment ten times that of alkali atoms and equal only to terbium as the most magnetic atom, are expected to exhibit a multitude of fascinating collisional dynamics and quantum dipolar phases, including quantum liquid crystal physics. We report the first laser cooling and trapping of half a billion Dy atoms using a repumper-free magneto-optical trap (MOT) and continuously loaded magnetic confinement, and we characterize the trap recycling dynamics for bosonic and fermionic isotopes. The first inelastic collision measurements in the few partial wave, 100 uK--1 mK, regime are made in a system possessing a submerged open electronic f-shell. In addition, we observe unusual stripes of intra-MOT $<$10 uK sub-Doppler cooled atoms. We will also discuss progress toward narrow-line cooling Dy to the 1 uK regime. [Preview Abstract] |
Saturday, May 29, 2010 11:00AM - 11:30AM |
X1.00002: Probing two-electron dynamics in helium with isolated attosecond pulses Invited Speaker: High contrast single isolated XUV pulses with duration less than 150 as were generated with a double optical gating. When a helium atom is exposed to the attosecond field with photon energy above 60 eV, it is ionized through two quantum channels, i.e., the direct ionization from the ground state and the autoionization from the doubly-excited states. We demonstrated that by combining the attosecond pulse with a few-cycle femtosecond field, the lifetime of the doubly-excited states could be measured. Furthermore, the interference between the two quantum channels was controlled by the intense near infrared laser pulse. [Preview Abstract] |
Saturday, May 29, 2010 11:30AM - 12:00PM |
X1.00003: Observation of an unusually large atomic parity-violation effect Invited Speaker: We report on observation of a large parity-violation effect in the atoms of ytterbium (Yb). This left-right asymmetry appears naturally in the Standard Model, and is associated with the exchange of a virtual heavy ``gauge" boson between subatomic particles. Eventually, parity violation has been observed and precisely measured by a number of groups in several different atoms, culminating in a 0.3\% measurement in cesium (Cs) by Carl Wieman and co-workers at Boulder. The parity-violating amplitude of the 6x$^2$ $^1$S$_0$ $\rightarrow$ 5d6s $^3$D$_1$ 408-nm forbidden transition of ytterbium is found to be two orders of magnitude larger than in cesium. This is the largest atomic parity-violating amplitude yet observed. This also opens the way to future measurements of the parity violation effects for different Yb isotopes in order to test the effect of the neutron distributions within the nucleus and detect the so-called ``anapole moment" by comparing parity-violating amplitudes for various hyperfine components of the transition. So far, Cs is the only system where such a moment has been detected. Measurements of anapole moments are important for understanding the electroweak interactions within the nucleus which are hard to probe by other means. [Preview Abstract] |
Saturday, May 29, 2010 12:00PM - 12:30PM |
X1.00004: Spectroscopy and Reactions of Hydrocarbon Radicals in 0.4 Kelvin Helium Nanodroplets Invited Speaker: Helium nanodroplet isolation (HENDI) has proven to be a versatile technique for many forms of molecular spectroscopy. Helium nanodroplets provide a medium for studying at 0.4 Kelvin, the structure and dynamics of novel systems such as free-radicals, metal clusters, and molecular clusters. In this talk, I will discuss recent progress towards the application of HENDI for the characterization of hydrocarbon radicals and their reactions with O$_2$. The infrared spectra of methyl (CH$_3$), ethyl (C$_2$H$_5$), and propyl (C$_3$H$_7$) radicals are obtained using a high temperature, low pressure, effusive pyrolysis source for doping the droplets. Comparisons to previous gas phase spectroscopy studies reveal a negligible influence of the helium environment on the structure of these radicals. The pyrolysis source and a gas pick-up cell are used to sequentially dope each helium droplet with a single hydrocarbon radical and a single O$_2$ molecule. The resulting products of the low temperature reaction between the radical and O$_2$ are probed spectroscopically downstream from the pick-up zones. [Preview Abstract] |
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