PEGASUS Seminar Series: Structure and dynamics of materials under pressure (Xue Yong)

Please join us this Tuesday, August 16 in Physics 175 for our next presentation in our PEGASUS Summer Seminar Series.
Our next speaker is Xue Yong, who studies the effects of pressure and temperature on materials.
There will be cookies and refreshments served beforehand at 3:00 pm in the lounge for those attending the seminar.
Title: Structure and dynamics of materials under pressure
Abstract: The response of a material to increasing pressure and temperature is an interesting and practical research that attracts many investigator in geophysics and geochemistry, as well as in material science. High pressure and temperature provide large compression energy (PV) and thermal (TS) energies, which are able to break intermolecular or intra-molecular interactions in most stable materials. Therefore, at extreme conditions, most ambient-pressure liquid and solid materials become unstable and transform into new phases with higher densities. In this talk I am going to present some interesting results bout the response of materials to high pressure by computer simulation. Three examples will be presented. First is the using of high pressure technique to synthesis high energetic materials based extended CO2. Second is the novel interactions of silicate with small molecular gas at high pressure and temperature. Third is the a new sheared – ice-Ih under moderate pressure

PEGASUS Seminar Series: Investigation of Solar Influence on Thermospheric Density Variation (Clifford Ridley)

Please join us this Tuesday, August 2nd in Physics 175 for our next presentation in our PEGASUS Summer Seminar Series.
Our next speaker is Clifford Ridley from ISAS, who investigates the effects of the interaction of the Sun’s magnetic field with the earth on particles in the thermosphere.
There will be cookies and refreshments served beforehand at 3:00 pm in the lounge for those attending the seminar.

Title: Investigation of Solar Influence on Thermospheric Density Variation

Abstract: Due to undulations in the heliospheric current sheet, the Earth’s orbit is divided into sectors where the sun’s interplanetary magnetic field (IMF) at the Earth is primarily directed towards or away from the sun. During the year 2003, the IMF direction at the Earth changes with a nearly consistent periodicity of 12-15 days, leading to well defined IMF sectors. During this same period, thermospheric neutral particle densities and electron content are higher during times when the IMF is directed towards the sun, and lower when the IMF is directed away from the sun. Possible links between the IMF polarity and thermospheric densities were investigated, with a focus on the spatial distribution of thermospheric density variations between IMF sectors, as well as the temporal changes of solar wind and IMF parameters and geomagnetic activity indices during the Earth’s transition between IMF sectors.

PEGASUS Seminar Series: Exact Solutions to Einstein-Maxwell theory (Vineet Kumar)

Please join us this Tuesday, July 26 in Physics 175 for our next presentation in our PEGASUS Summer Seminar Series.
Our next speaker is Vineet Kumar, who studies electromagnetic behaviour in curved spacetime.
There will be cookies and refreshments served beforehand at 3:00 pm in the lounge for those attending the seminar.
Title: Exact Solutions to Einstein-Maxwell theory
 
Abstract: We construct explicit analytical exact solutions to the four and higher dimensional Einstein-Maxwell theory. All solutions are constructed by embedding a solution to Einstein equations in higher dimensions. Several solutions will be briefly discussed including two helicoidal solutions, one embedding Schwarzschild and one embedding the Eguchi-Hanson space. In the case of the Eguchi-Hanson embedded solution, we find that the solutions can be extended to non-stationary exact solutions to Einstein-Maxwell theory with cosmological constant and that the solutions are asymptotically expanding patches of de-Sitter spacetime.

PEGASUS Seminar Series: The hidden world – Higgs, dark matter and conformal symmetry (Zhi-Wei Wang)

Please join us this Tuesday, July 19th in Physics 175 for our next presentation in our PEGASUS Summer Seminar Series.
Our next speaker is Zhi Wei Wang, who investigates models to solve important problems in physics including dark matter.
There will be cookies and refreshments served beforehand at 3:00 pm in the lounge for those attending the seminar
 
Title:The hidden world: Higgs, dark matter and conformal symmetry
 
Abstract: This talk will address the two most important topics in particle physics in the LHC era: Higgs and dark matter. The Higgs mass suffers from the well-known hierarchy/naturalness problem and a custodial symmetry is needed. In this talk, I will show conformal symmetry as a non-conventional custodial symmetry protects the Higgs mass from UV sensitivity. In addition, the Standard Model with hidden sector extensions provide ideal dark matter candidates and interesting collider signatures. Combining the idea of conformal symmetry and hidden sectors, I will introduce the conformally-symmetric hidden sector where both the hierarchy problem and dark matter are addressed.

PEGASUS Seminar Series: P-block elements – the next generation (Thomas Tolhurst)

Please join us this Tuesday, July 12th in Physics 126 (please note the temporary room number change!for our next presentation in our PEGASUS Summer Seminar Series.
Our next speaker is Thomas, who studies the properties of materials using computational methods and experimental techniques such as soft x-ray spectroscopy.
There will be cookies and refreshments served beforehand at 3:00 pm in the lounge for those attending the seminar.
Title: P-block elements – the next generation
Abstract:

Soft x-ray spectroscopy is an experimental technique that provides a unique perspective on many
important material properties. When combined with first principles electronic structure calculations, everything from the bulk band gap, to site-specific charge densities can be determined and understood. This talk will look at the application of these techniques to several technologically important nitrides and oxides, and emphasize how they can provide information on the structure-property relationships that are key to engineering new materials

PEGASUS Seminar Series: 1^{-+} Light Hybrid Mesons and QCD Sum Rules (Zhuoran Huang)

Please join us this Tuesday, July 5th in Physics 175 for our next presentation in our PEGASUS Summer Seminar Series.
Our next speaker is a visiting doctoral candidate, Zhuoran Huang, who studies exotic hadronic structures beyond the quark model.
There will be cookies and refreshments served beforehand at 3:00 pm in the lounge for those attending the seminar.
Title: 1^{-+} Light Hybrid Mesons and QCD Sum Rules
Abstract:

There is intense activity in the search of glueballs, light hybrids and multiquark states, either as supernumerary states with ordinary quantum numbers JPC, or as genuine exotics with JPC that cannot be matched by ordinary quantum numbers. In particular, evidence has been found for 1-+ states between 1 and 2 GeV by VES at Serpukhov, by E852 at Brookhaven, and by COMPASS at CERN, and the search continues at JLab by GLUEX. The structure of these states are still ambiguous. Four-quark states and hybrid states are the most possible explanations. To study these non-qq resonances beyond the conventional quark model, the Wilson coefficients of dimension-8 condensate contribution to the current-current correlator of 1−+ light hybrid current gq(x)γνiGμν(x)q(x) are calculated. With inclusion of these higher-power corrections and updating the input parameters,  the mass of the 1−+ light hybrid meson are re-analyzed from Monte-Carlo based QCD sum rules. In this talk, the basic idea of the quark model and QCD sum rules will be briefly reviewed and then the results of calculation and numerical analysis will be presented.

PEGASUS Seminar Series: Remote Sensing of the Atmosphere with Limb Scattered Sunlight (Daniel Zawada)

Please join us this Tuesday, June 14th for our next presentation in our PEGASUS Summer Seminar Series.
Our next speaker is Daniel Zawada, who studies atmospheric aerosols using OSIRIS.
There will be cookies and refreshments served beforehand at 3:00 pm in the lounge for those attending the seminar.
Title: Remote Sensing of the Atmosphere with Limb Scattered Sunlight
Abstract: Instruments such as the Optical Spectograph and InfraRed Imaging System (OSIRIS) have been taking spectral measurements of the atmospheric limb for more than a decade.  The measurements can be inverted to obtain vertical number density profiles of trace species in the atmosphere, in particular, upper tropospheric and lower stratospheric ozone and sulfate aerosols.  This talk will present an overview of the limb scatter technique and its advantages and disadvantages. We will focus on the tools and methods needed to invert the measurements to obtain vertical profiles of trace species.

PEGASUS Seminar Series: An Overview of Dark Matter Phenomenology (Fred Sage)

Please join us this Tuesday, June 7th for our next presentation in our PEGASUSSummer Seminar Series.
Our next speaker is Fred Sage, who researches particle dark matter and how to find it.
There will be cookies and refreshments served beforehand at 3:00 pm in the lounge.
Title: An Overview of Dark Matter Phenomenology

Abstract: The majority of matter in the universe is nonluminous and of unknown composition. It has been dubbed ‘dark matter’ for these reasons. The dark matter problem is one of the most pressing problems in both particle physics and astrophysics. This talk will provide an overview of the study of dark matter from a particle physics perspective. The evidence for the existence of dark matter will be reviewed, and the motivations for particle models of dark matter will be discussed. The talk will conclude with a description of experimental and observational searches for dark matter, including nuclear recoil searches, cosmic ray signals, and production in particle colliders.

PEGASUS Seminar Series: Investigating the Ion thermodynamics of the F region ionosphere (Lindsay Goodwin)

Please join us this coming Tuesday for our next presentation in our PEGASUS Summer Seminar Series.
Our next speaker is Lindsay Goodwin, who investigates ion thermodynamics in the ionosphere.
Please join us this Tuesday at 3:00 pm in the lounge for cookies and refreshments beforehand.
As well, please join us after the seminar for pizza and refreshments and take part in our Annual General Meeting.
Title: Investigating the Ion thermodynamics of the F region ionosphere.

Abstract: Ion heating by friction with neutral particles is known to have a significant impact on the F-region ion temperature in the presence of large electric fields, particularly when the ions become supersonic relative to the neutral background population with which they collide. However, what has not been fully characterized is the impact this heating has on ion temperature anisotropy, as well as the influence of these non-Maxwellian velocity distributions on the shape and interpretation of incoherent radar spectra. To study this, reconstructions of incoherent radar spectra made from Monte-Carlo simulations of velocity distributions are being analyzed along-side radar campaigns capable of giving insight into such things as the collision cross-section of different collisions (such as the resonant charge exchange of O+ ions with O). For this research, an experiment was devised to scrutinize the plasma along the magnetic meridian so as to extract electric field and ion temperature information at altitudes where frictional heating plays an important role. The results of this work indicate that, as expected, the line-of-sight component of the plasma drift extracted from different altitudes is consistent throughout the ionosphere above 150 km. However, owing to competition with processes such as heat exchange with electrons, neutral atmospheric uncertainties, and heat conduction from above, extracting information about the effect of frictional heating is difficult unless the electric field is very strong.  Here, the first electric field and ion temperature results from these special magnetic meridian scanning modes will be shown.

PEGASUS Seminar Series: Space Weather – Finding Field-Aligned Currents during Substorms (Gaelene Lerat)

Please join us this coming Tuesday for our next presentation in our PEGASUS Summer Seminar Series.
Our next speaker is Gaelene Lerat, who investigates atmospheric plasma dynamics utilizing both satellites from the AMPERE project as well as SuperDARN data.
Please join us this Tuesday at 3:00 pm in the lounge for cookies and refreshments beforehand.

Title:  Space Weather: Finding Field-Aligned Currents during Substorms

Abstract: Near-Earth space is a region whose dynamics are best described by plasmas and the currents they form.  To understand the chain of events that leads to space weather phenomena, the connections of the solar wind to the magnetosphere to the ionosphere by such currents need to be understood.  In particular, during substorms currents are formed between the magnetosphere and the ionosphere, and a view of incoming and outgoing currents would illustrate the structure of what is called the substorm current wedge.  Two scientific tools are considered to do just that in this presentation: the magnetometers aboard the Iridium satellite constellation in the AMPERE project and the radar network SuperDARN.  A comparison between AMPERE and SuperDARN methods will be given, as well as the results for a superposed epoch analysis for AMPERE (SuperDARN results up-and-coming).