The 2009 PAGE conference Abstracts

Abstracts:

Dr. Tom Kirchner (Invited Speaker)

Atomic systems in time-dependent fields:
insights into the fundamental few-body problem
The quantum mechanical few-body problem has challenged physicists ever since the foundations of quantum theory were laid in the 1920s. It might be embarrassing, but even if the mutual forces between the particles are known the solutions of the fundamental equations are not except for a few special cases.

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.

Steve Beale

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.

Ioannis Haranas

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.

Daniel Fitzakerley

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.

Laura Chajet

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.

Robert Berthiaume

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.

Jesse Rogerson

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.

Yaniv Gura

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.

The 2007 Golden lion tamarin conference Abstracts

Abstracts:

Alireza Rafiee

Quasar lifetime and Black Hole Spin Quasars seem to have a limited lifetime
They continuously accrete matter and gain angular momentum but the increase on radiative efficiency of that system remains limited to a physical upper bound. Using that physical barrier, we have estimated an upper limit for quasar lifetime.

Steve Beale

Measuring Bs mixing at the Fermilab Tevatron
Neutral Bs mesons (b-bar s) will spontaneously transform into their anti-particle (and visa versa) by a weak process known as mixing. Measurement of the mixing frequency provides an important constraint on the electroweak coupling of s and d quarks with the top quark. Presently, the only place where this measurement can be made is at the Fermilab Tevatron, a proton-antiproton collider with a center of mass energy of 1.96 TeV. The D0 detector is one of two collider detectors at Fermilab currently working to make this measurement. After a short overview of the Tevatron, the D0 Detector, and general mixing phenomenology, I will present the latest mixing measurement from D0.

Tzahi Yavin

Modelling Markets
In the last quarter of a century or so, the sophistication of the mathematical modeling of financial markets has witnessed a tremendous increase. In this talk I will briefly discuss one of the corner stones in this field, the Black-Scholes model, and how it is used to price options for stocks trading on the stock exchange.

Yan Sun

Density functional study of 13-atom transition-metal clusters and bimetallic A_4B_12 clusters

Min zhang

Global optimization of 13-atom 5d transition metals
We did structural global optimization for six 5d transition metals(Ta-Pt). Two optimization algorithms, Tabu Search in Descriptor Space(TSDS) and Simulated annealing (SA), were used and their performances were compared. Energy evaluation was done with PBE exchange-correlation functional implemented by VASP. Due to complexity of the multiplicities of transition metals, we did calculations with full relaxation of multiplicity. Amazingly, we found none of them had an icosahedral ground state structure. We compared thoroughly our results with previously reported structures. Calculations show that our results are the best. To rule out the difference could be introduced by choice of functional, we did local optimization for our results and structures reported by other researchers with LDA and PW91. The LDA and PW91 functionals give similar results to PBE and confirm that we found the best structures to date for these clusters.

Brynle Barrett

Interferometric Measurement of the Fine Structure Constant using Cold Rubidium
Atoms in an Atomic Fountain One of the most challenging questions in astrophysics today is to establish when and how the universe became (re)ionized. Although it is accepted that the overall process is well understood, and in spite of the observational and theoretical progress that have been made in the last few years, there are still many details that remain controversial and unsolved. At a redshift z ~ 6 we are approaching to the end of Epoch of Reionization, but the number of known quasars and galaxies close to this redshift is still very low, thus the uncertainties are large. To improve our knowledge of that fundamental epoch we need to find more high redshift sources. Here, I will briefly summarize some of the basic ideas on this topic and present the description of the data we are working on and the procedure we have followed.

Edward Ackad

Supercritical Collisions with no intial electrons Colliding two fully ionized
Uranium atoms can lead to pair creation, but solving for a collision with no initial electrons is not commonly done. I will show how it is possible to solve for this system and show results of current work were we can show the enhancement of the positron production due to the decay of supercritical resonance state for collisions with some nuclear sticking.

The 2007 Golden lion tamarin conference

When: August 30th, 2007
Where: Ross S137 (Number 30 in York map)

To present a talk in the conference, please send an email to the president of the PAGE.
Attendance is free. We strongly encourage graduate students to participate this event.

Organizing Committee:

Alireza Rafiee arafiee@yorku.ca
Brynle Barrett bbarrett@yorku.ca
Carson Mok cmok@yorku.ca
Edward Ackad eackad@yorku.ca (Chair of the Organizing Committee)

Conference Schedule:

Time Speaker
9:45 Reception
10:00 Opening
10:15 Alireza Rafiee
10:30 Tzahi Yavin
10:45 Min Zhang
11:00 Coffee break
11:15 Victoria Martynenko
11:30 Yan Sun
Lunch Provided by PAGE
1:00 Steve Beale
1:30 Brynle Barrett
1:45 Edward Ackad
2:00 Closing

About the Lion Tamarins:

Lion tamarins have a mane derived from long hairs on the top of the head, cheeks and throat. The golden lion tamarin’s color is predominantly golden with occasional orange, brown or black coloration on the tail and forepaws. It weighs about 0.5 kg (1.1 lb) and averages about 25 cm (10″) in head/body length, not counting the tail. The golden lion tamarin prefers primary lowland tropical forest from sea level to 1000 m (3300′). Golden lion tamarins are omnivorous, feeding on fruits, gum, nectar, insects, and small vertebrates. The golden lion tamarin is diurnal and predominantly arboreal. It is usually found at heights of 3 – 10 m (10 – 30′) above the forest floor. It sleeps there at night in tangled vegetation or, more often, in a hole in a tree, such as an abandoned woodpecker nest. Most golden lion tamarins live in reproductive groups that occupy stable territories. The average number of individuals/group in one study was 5.4. In the wild, groups usually consist of one breeding adult of each sex and younger animals. Golden lion tamarins are cooperative breeders: all adult members of a group help to carry and feed the offspring of the group, with the adult male commonly doing the largest share. The mother only takes the babies to nurse them. In the 19th century, the golden lion tamarin occurred in Brazil in the coastal forests of the states of Rio de Janeiro and Espirito Santo. By the early 1980’s it was known only from remnant forests in the state of Rio de Janeiro in an area of occupied habitat probably totaling considerably less than 900 sq km (350 sq mi). The wild population is currently fragmented into 17 different subpopulations in isolated forest patches throughout its small range. More than 90% of the original Atlantic coastal forest, which contains the golden lion tamarin’s habitat, has been lost or fragmented to obtain lumber and charcoal and to clear out areas for plantations, cattle pasture, and development. Capture for zoos and private collections also contributed to its decline in the past. The golden lion tamarin is still under severe threat from continued deforestation, much of which is undertaken to create weekend beach properties. Less than 2% of the forest remains in the region where the golden lion tamarin lives.

Source: animalinfo

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The Monthly Optical Video Interactive Entertainment Night

We have started a Monthly Optical Video Interactive Entertainment night this year. We hope to make this MOVIE night the best opportunity to hang out and get know each other in a social setting. We can enjoy watching an optical video as we enjoy our colleagues’ company and free pizzas, pop and snacks. To make this night even more special, we sometimes raffle the DVD off to one of the participants at random. So come on in and enjoy the MOVIE with us. Say goodbye to your computer or your research for a couple of hours and enjoy a normal social life. It will be fun, (believe me!) and you will be refreshed. You can even work harder after that. Here is how you can find more about the MOVIE night:

New Event:

  • Event Title: No events scheduled until October 2008
    When: TBA

    Where: 315 PSE
  • Previous Events:
    2008, March
    2008, February
    2007, October

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The Orientation party

So you ‘re accepted to the York Graduate Program in Physics and Astronomy. Good for you! You may want to know about some of the ground rules or library resources or you may simply want to know about the people here. This orientation party makes it possible to meet colleagues, hear news about new regulations or rules and new facilities available to graduate students. You can also ask questions about unclear things. We can enjoy free pizza, pop and snacks as we start a new school year with new people. We have a great mentor, Mrs. Marlene Caplan. She kindly explains all the regulations and answers all of your questions.

  • When: September 15, 2010. from 12:00pm to 1:30pm
  • Where: 317 PSE

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