Collisions of atoms and molecules as well as their interactions with laser radiation are well suited to illustrate this worrisome, but also fascinating situation. They will be the topic of my talk. In particular, the role of theory and computations will be discussed and some recent results and insights deduced from them will be presented.
Dr. Veronica Sanz (Invited Speaker)
Having fun at the energy frontier
Many hopes hang on the Large Hadron Collider. Among many conundrums in Particle Physics,the LHC is expected to reply to these questions: what is the origin of mass? which particleis responsible of Dark Matter in the Universe? are there more dimensions than the four we experience everyday? are matter and energy secretly related? In this talk I will outline how the LHC is going to look for those answers during its first years of running.
Searching for Charge-Parity Violation
The visible universe is composed of almost entirely matter with little or no antimatter. However, matter particles are always produced with an antimatter partner, hence there should be a balance of matter and antimatter. This is the baryon asymmetry problem. To account for this asymmetry, there must be new sources of Charge-Parity (CP) violation. One possible source is matter-antimatter oscillations in the Bs meson system. An asymmetry in the transition rate to/from matter to antimatter would be a clear indication of CP violation. This effect is predicted to be very small in the standard model of particle physics, but may be enhanced by new physics. I will present a measurement of this CP violating charge asymmetry and show how impacts current searches for new physics.
Satellite motion in a non-singular gravitational potential
The scope of this paper is to study the effects of a non-singular gravitational potential on satellite orbits by deriving the time rates of change of its orbital elements. This is achieved by writing a non-singular potential expression as a function of the orbital elements and then substituting it into the Lagrange planetary equations. In particular, we derive expressions for high and low frequency as well as secular effects and we evaluate them numerically using the low Earth orbiting satellite mission GRACE. We compare the secular effects with the corresponding general relativistic results and we show that the secular effect of the first disturbing term R1 on the perigee shift is equal to
, an effect that most likely will not be easily separated from the corresponding relativistic that is three times greater in magnitude. Finally, the effect of R2 term on the time rates of change of the perigee and mean anomaly for missions like GRACE will not be easily observed since they would also require extremely long orbiting time scales.
Precision Measurement of the 23P2 -to- 23P1 helium Fine Structure Interval
The fine structure constant, α, is a fundamental constant of nature that represents the strength of the coupling interaction between charged particles. Comparisons of experimental values and theoretical predictions of the n=23PJ fine structure intervals of Helium can be used to determine α. The goal of my research is complete a measurement of the 23P2-to-23P1 interval to a precision of 90 Hz (40 ppb). This level of precision is reached by using the Ramsey separated oscillatory field technique wherein the natural linewidth is narrowed using a pair of microwave pulses. This work builds on a 150 ppb measurement completed by our group last year (Phys. Rev. A 79, 060503 (2009): Borbely et al.). If the larger 23P1-to-23P0 interval is measured with the same precision as the smaller 23P2-to-23P1 interval using this technique, the fine structure constant, α, will be determined to a precision of 1.5 ppb.
Maria Georgina Carrillo Ruiz
Field theories on a lattice with many flavours
Interest in non-Abelian lattice gauge theories with many flavours has increased in recent years. These studies aim to address physics that may appear at the energy of the Large Hadron Collider or beyond. In particular, the knowledge of the phase diagram of these theories as a function of the number of colors, flavours and matter representation plays a fundamental role when trying toconstruct viable extensions of the Standard Model. In this talk, we review the lattice formulation of such theories and take SU(2) gauge theory as a casestudy.
MHD Modeling of Disk Winds
Broad emission lines (BELs), one of the characteristic features of active galaxy nuclei (AGNs) spectra, are generally single-peaked and blueshifted with respect to the rest frame wavelength. It has been shown (e.g. Murray & Chiang 1997) that these observational results can be explained by assuming that the emission is produced in a wind off the accretion disk surrounding the central black hole. This feature was also explained by Emmering et al. (1992), but considering a magnetocentrifugal wind consisting of clouds. Here we present some preliminary results of the combination of both approaches considering a magnetocentrifugal continuous outflow.
A Low Cost MOPA System for Laser Spectroscopy
The low cost and robust nature of diode lasers make them suitable for applications in manufacturing, telecommunications, medicine and data handling. Further, they can be configured to have a very narrow linewidth and to be highly tunable, which makes them an attractive tool for spectroscopic research. I will present an overview of a campaign to develop a homebuilt Master Oscillator Powered Amplifier system which includes External Cavity Diode Lasers, Tapered Amplifiers, and Optical Isolators. The master oscillator is built with the same laser diode found in most CD players. The system produces a 600mW single mode beam at 780nm for a tenth of the cost of commercially available systems. Applications include magneto-optical trapping, atom interferometry, and inertial sensing.
An overview of Giant arcs
Recently, multiple examples of giant arcs created by gravitational lensinghave been discovered. Due to the magnification properties of lensing, these systemsprobe fainter sources than otherwise possible, resulting in extending galaxy/quasarstudies to higher redshifts. Also, due to their high redshift and extended image,these sources provide a unique look at the intergalactic medium. In this talk, Iwill highlight a few examples of giant arcs, and summarize the key conclusions reached by studying these lensing systems.
The Creation of the H−+ Atom
Our goal is to create, detect and study an exotic atom made up of an H- ion along with a positron. Our 1st goal toward eventual spectroscopic measurements of this exotic atom is to create it in a highly excited state and detect it. A bound molecule made up of these constituents (positronium hydride) has been indirectly detected by colliding positrons with methane gas and looking for CH3+ [D. M. Schrader et al, PRL 69, 57]. Our research will produce a positronic atom in a Rydberg state with the positron weakly bound to the H- ion in an atomic configuration rather that H bound to Ps in a molecular state. A beam of H- ions will be directed towards a cloud of positrons that will be waiting in a particular potential well created by a trap consisting of a series of consecutive aluminum and copper hollow cylinders, called electrodes. The H− ions will undergo some process emerging with a positron orbiting at a Rydberg state. Further down the electrode stack the H−+ atom will encounter a strong electric field gradient created by the electrodes. This will strip the positron from the H−+ atom which will allow us to accumulate and detect the stripped positrons. The detection of the positrons in this ionizing potential well will be evidence of the production of H−+ atoms. Tedious optimization has led to a record number of approximately 6.5 million accumulated positrons for this apparatus over 120 seconds and a 100nA beam of H- ions has been produced using a Colutron Ion Gun. Production of this atom will open the door to precise spectroscopic measurements of this atom and may provide greatly improved understanding of the H− ion core.