[PEGASUS] Summer Seminar Series: Caelia Gardiner

Please join us this Tuesday, June 20 in Physics 175 for our next presentation in our PEGASUS Summer Seminar Series.
Our next speaker is Caelia Gardiner, who studies oxygen spectral emissions in the mesosphere and lower thermosphere.
There will be cookies and refreshments served beforehand at 3:00 pm in the lounge for those attending the seminar.
Title: Oxygen A Band Emission in the SaskTran Radiative Transfer Framework
Abstract:
Oxygen emission is a contributor to day glow in the mesosphere and lower thermosphere (MLT). The emissions occur in the atmospheric band of oxygen, which ranges from 629 nm to 762 nm, and corresponds to oxygen’s second electronic excited state. There are three vibrational levels within the atmospheric band, with the A band representing the lowest level. Emissions in the A band are centred around 762 nm and are the most significant contributor to oxygen emissions in the atmospheric band. The SaskTran radiative transfer framework is a software model that simulates light propagation through the atmosphere to produce radiance profiles. While it currently includes oxygen absorption in the A band, oxygen emission has yet to be implemented. Modelling the volume emission rate of oxygen molecules in the A band by use of HITRAN data and photochemical processes will provide the information necessary to simulate oxygen emission with SaskTran. This work is also done in support of the Swedish satellite MATS (Mesospheric Airglow/Aerosol Tomography and Spectroscopy), which will take optical measurements of mesospheric gases. Understanding the process of oxygen A band emission through simulation and measurement will improve scientific understanding of the MLT and provide valuable data for other atmospheric study.

[PEGASUS] Summer Seminar Series: William Elcock

Please join us this Tuesday, June 13 in Physics 175 for our next presentation in our PEGASUS Summer Seminar Series.
Our next speaker is William Elcock, who studies hysteresis in perovskite solar cells.
There will be cookies and refreshments served beforehand at 3:00 pm in the lounge for those attending the seminar
 
Title: Hysteresis in Perovskite Solar Cells
 
Abstract:
Perovskite solar cells have demonstrated power conversion efficiencies (PCEs) greater than 20%. However, current density-voltage (J-V) hysteresis (i.e. a difference in photocurrent between forward and reverse scans) makes it difficult to determine the true PCE of perovskite solar cells. The mechanism behind this hysteretic behaviour is not yet fully understood. However, the accumulation of halide ions at the perovskite active layer/contact interface has been put forward as a possible explanation behind this phenomenon. With this talk, I will give a background on hysteretic phenomena and the challenges posed by hysteresis in perovskite solar cells. I will also explain how the proposed ion migration mechanism results in hysteretic behaviour.

[PEGASUS] Summer Seminar Series: Jason Ho

Please join us this Tuesday, June 6 at 3:30 pm in Physics 175 for our first presentation in our PEGASUS Summer Seminar Series.
Our first speaker is Jason Ho, who studies exotic hadrons in the context of QCD sum rules.
There will be cookies and refreshments served beforehand at 3:00 pm in the lounge for those attending the seminar.
Title: Calculation of Open-Flavour Heavy-Light Hybrid Mass Spectrum from QCD Sum Rules
Abstract:
Our current understanding of the strong interaction (QCD) permits the construction of colour singlet states with novel structures that do not fit within the traditional quark model, including hybrid mesons. To date, though other exotic structures such as pentaquark and tetraquark states have been confirmed, no unambiguous hybrid meson signals have been observed. However, with data collection at the GlueX experiment ongoing and with the construction of the PANDA experiment at FAIR, the opportunity to observe hybrid states has never been better.
As theoretical calculations are a necessary piece for the identification of any observed experimental resonance, we present our mass predictions of heavy-light open-flavour hybrid mesons using QCD Laplace sum-rules for all scalar and vector $J^{P}$ channels, and including non-perturbative condensate contributions up to six-dimensions.

2017 PEGASUS Summer Seminar Series

Summer is coming, which means the PEGASUS Student Summer Seminar Series will be starting up again.

Each summer, PEGASUS organizes a seminar series that provides an opportunity for graduate students in the department to share their research and practice their presentation skills in a friendly environment. The audience consists of only graduate and undergraduate students, so the environment is far more relaxed and informal than departmental seminars or conference sessions. Talks are 30-45 minutes long with questions from the audience.

These sessions provide graduate students with the perfect environment to hone their presentation skills, so if you have an presentation in the department or a summer conference you are preparing for, consider taking part.

To claim your spot for this year, message us on our Facebook page, or email your local PEGASUS representative.

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.