Coherent manipulation of cold Rydberg atoms near the surface of an atom chip

Coherent superpositions of the 49s and 48s Rydberg states of cold Rb atoms were studied near the surface of an atom chip. The superpositions were created and manipulated using microwaves resonant with the two-photon 49s-48s transition. Coherent behavior was observed using Rabi flopping, Ramsey sequences, spin-echo and spin-locking. These results are discussed in the context of Rydberg atoms as electric field noise sensors. We consider the coherence of systems quadratically coupled to noise fields with 1/f^k power spectral densities (k \approx 1).Comment: 11 pages, 7 figure

Extending the automated zoning procedure to reconcile incompatible zoning systems

This paper concerns the problem of matching incompatible zonal geographies, for example in the context of comparing census outputs over time. The automated zoning procedure (AZP) proposed by Openshaw (1977) is reviewed and extended to permit its application to the intersection of two zonal systems. A population stress statistic is proposed which may be used in the extended AZP algorithm in order to maximise the match between two zonal geographies. An implementation of this approach is described, and illustrated by reference to UK Census dat

Chirality waves in two-dimensional magnets

We theoretically show that moderate interaction between electrons confined to move in a plane and localized magnetic moments leads to formation of a noncoplanar magnetic state. The state is similar to the skyrmion crystal recently observed in cubic systems with the Dzyaloshinskii-Moriya interaction; however, it does not require spin-orbit interaction. The non-coplanar magnetism is accompanied by the ground-state electrical and spin currents, generated via the real-space Berry phase mechanism. We examine the stability of the state with respect to lattice discreteness effects and the magnitude of magnetic exchange interaction. The state can be realized in a number of transition metal and magnetic semiconductor systems

The GALEX Extended Mission: Surveying UV Tracers of the Hidden Side of Galaxy Evolution

The Galaxy Evolution Explorer (GALEX) continues its surveys of the ultraviolet sky. GALEX surveys have supported the following galaxy evolution investigations: calibrating UV as a star formation rate tracer, using wide and deep surveys to measure star formation history, studying the evolution of dust extinction and metallicity, selecting and analyzing galaxies in transitory states, finding local analogs to Lyman Break Galaxies, probing and time-dating star formation in a wide variety of physical regimes. Our continuing mission is focussed on relating star formation history and galaxy evolution paths to the properties of dark matter halos and their assembly history, and on beginning to relate the evolution of galaxies to that of black holes and the intergalactic medium. GALEX has proven that the UV is an ideal band to find and map star formation in low mass, low density objects, and potentially in primordial gas. With future UV missions it may be possible to map emission from the intergalactic and circum-galactic medium, and make a definitive connection between galaxy evolution and the cooling, accretion, heating, and enrichment of gas in the cosmic web

Effect of the Magellanic Clouds on the Milky Way disk and VICE VERSA

The satellite-disk interaction provides limits on halo properties in two ways: (1) physical arguments motivate the excitation of observable Galactic disk structure in the presence of a massive halo, although precise limits on halo parameters are scenario-dependent; (2) conversely, the Milky Way as a whole has significant dynamical effect on LMC structure and this interaction also leads to halo limits. Together, these scenarios give strong corroboration of our current gravitational mass estimates and suggests a rapidly evolving LMC.Comment: 12 pages, 8 Postscript figures, uses paspconf.sty. To appear in the Third Stromlo Symposium: The Galactic Halo (ASP Conference Series), in press. HTML version available at: http://www-astro.phast.umass.edu/~weinberg/stroml

Kinematic Signature of a Rotating Bar Near a Resonance

There have been several recent suggestions that the Milky Way has rotating bar-like features based on HI and star count data. In this paper, I show that such features cause distinctive stellar kinematic signatures near OLR and ILR. The effects of these resonances may be observable far from the peak density of the pattern and relatively nearby the solar position. The details of the kinematic signatures depend on the evolutionary history of the `bar' and therefore velocity data, both systemic and velocity dispersion, may be used to probe the evolutionary history as well as the present state of the Galaxy. Kinematic models for a variety of simple scenarios are presented. Models with evolving pattern speeds show significantly stronger dispersion signatures than those with static pattern speeds, suggesting that useful observational constraints are possible. The models are applied to the proposed rotating spheroid and bar models; we find: 1) none of these models chosen to represent the proposed large-scale rotating spheroid are consistent with the stellar kinematics; and 2) a Galactic bar with semimajor axis of 3\kpc will cause a large increase in velocity dispersion in the vicinity of OLR (\sim5\kpc) with little change in the net radial motion and such a signature is suggested by K-giant velocity data. Potential future observations and analyses are discussed.Comment: 24 pages, AAS LaTeX macros v3.0, 23 figures (available on request

Summary Talk: First Workshop on Forward Physics and Luminosity Determination at the LHC

An attempt is made to summarize the discussion at the Workshop, except for the panel discussion on the ability of the LHC detectors to accommodate forward reactions. The Workshop focused on two main topics. The first topic was forward physics at the LHC. Predictions were made for forward reactions, including elastic scattering and soft diffractive processes, intopic was forward physics at the LHC. Predictions were made for forward reactions, including elastic scattering and soft diffractive processes, in terms of (multi) Pomeron exchange, using knowledge gained at lower energies. The survival probability of rapidity gaps accompanying hard subprocesses was studied. The nature of the Pomeron, before and after QCD, was exposed, and some aspects of small x physics at the LHC were considered. The second topic of the Workshop concerned the accuracy of the luminosity measuring processes at the LHC. Attention concentrated on three methods. The classic approach based on the optical theorem, secondly, the observation of the pure QED process of lepton-pair (l^+l^-) production by photon-photon fusion and, finally, the measurement of inclusive W and Z production.Comment: 21 pages,10 figures, LaTeX, Workshop at Helsinki, 31 October - 3 November, 200

Status of Structure Functions and Partons

We briefly review some of the developments in the study of parton distributions which have occurred since DIS2000, including discussion of uncertainties, shadowing, unintegrated and generalized distributions.Comment: 12 pages including 4 figures, summary of talk at DIS200