SUBMITTED POSTERS Rajni Bagga - McGill Physics · 2019-08-09 · SUBMITTED POSTERS June 25-28, 2019 McGill University, Montréal, QC In the last decade, extremely efficient first-principles

SUBMITTED POSTERS

McGill University, Montréal, QC June 25-28, 2019

We synthesised ZnO Nanorods arrays doped with and without Mn doping (at a 1% concentration of the precursor

salts) by a hydrothermal method at low temperature[1]. They were characterised by scanning electron microscopy

(SEM), Photoluminescence (PL) and electron paramagnetic (EPR) spectroscopy. SEM images shows that the introduc-

tion of the dopant does not preclude the formation of nanorods. All samples produced broad band Photolumines-

cence (PL) emissions in the yellow-orange-red range, typically attributed to defects in the crystalline structure [2].

The PL spectra does not seem to show significant changes in the ratio of the near band edge emission and the defect

emission with the Mn doping. From this, we infer that the crystal quality of the ZnO nanorods does not change with

Mn doping. As it can seen in the EPR spectrum from the ZnO nanoparticles formed in the growth solution tells the

presence of Mn in them.

1) A. Hassanpour, P. Guo, S. Shen, and P. Bianucci: The effect of cation doping on the morphology, optical and structural properties of highly

oriented wurtzite ZnO-nanorod arrays grown by hydrothermal method. Nanotechnology 28, 435707 (2017).

2) Fernanda C. Romeiro, Juliane Z. Marinho, Anielle Christine A. Silva, Nilo F. Cano, Noelio O. Dantas, and Renata C. Lima: Photolumines-

cence and Magnetism in {Mn}^{2+}- doped ZnO nanostructures grown rapidly by the

microwave hydrothermal method. J. Physical Chemistry C 2013, 117,26222- 26227.

Rajni Bagga Concordia University

HYDROTHERMAL GROWTH OF ZINC OXIDE NANO-RODS DOPED WITH MANGANESE

Taylor Bell McGill University

MASS LOSS FROM THE EXOPLANET WASP-12B INFERRED FROM SPITZER PHASE CURVES

As an exoplanet orbits its star, we see variations in the light emitted by the planet which are normally interpreted as

the planet’s hot and cold hemispheres rotating in and out of view. However, observations of the ultra-hot, Jupiter-

mass exoplanet WASP-12b show an anomaly; unlike every other planet observed to date, the infrared signal from

WASP-12b shows two peaks in brightness per planetary orbit, rather than one. Stranger still, this effect is seen only

at one wavelength, while the planet appears normal at a second infrared wavelength. This suggests we are seeing light

emitted from a dense stream of gas flowing directly from the planet to the star as the planet is slowly being con-

sumed.

SUBMITTED POSTERS


The field of quantum computing is of great interest to both the scientific and non-scientific community. However,

this field is not quite as advanced as the media portrays. Current efforts include evaluating the viability of two-level

quantum systems as 'qubits' – the physical unit of computation within a quantum computer. Despite many promising

candidate qubits, the possibility remains that a better qubit has yet to be found. An ideal qubit has both perfect isola-

tion from the surrounding environment in order to support long coherence times (the length of time that infor-

mation stored within the qubit is meaningful), as well as a reliable interaction mechanism to manipulate the qubit, and

permit communication between qubits. The spin states of an ionized atom of Selenium in a Silicon crystal (Si:Se+)

form a promising candidate qubit because they exhibit long coherence times and can be manipulated optically using

mid-infrared light. This spin-photon interface also lends itself to using the established silicon photonics industry,

which provides an avenue for connecting many qubits. In this talk I will introduce the Si:Se+ qubit and our most re-

cent results concerning the properties of the spin-photon interface.

Camille Bowness Simon Fraser University

CHARACTERIZATION OF THE SI:SE+ SPIN-PHOTON INTERFACE

Véronique Brousseau-Couture Université de Montréal

The electronic band gap is one of the most fundamental properties of semiconductors and insulators: it determines

the threshold of optical absorption and characterizes their electrical properties. More recently, tracking the variation

of the band gap with pressure or impurity doping has allowed the prediction of band inversions in many materials.

This phenomena is a signature of a topological phase transition, a field of research which has bloomed within the last

decade.

However, like all other electronic properties of materials, the band gap is affected by the atomic motion, though

electron-phonon interaction. As do many other types of interaction between fermions and massive bosons in many-

body physics, the electron-phonon interaction causes a renormalization of the electronic structure and gives a finite

lifetime to quasiparticle states, which can be observed in electron mobility experiments. As a consequence, the inter-

action of electrons with thermally excited phonons will induce a temperature-dependent variation of the band gap.

Moreover, since phonons are described by quantum harmonic oscillators, the band gap will be modified even at abso-

lute zero temperature, yielding a zero-point renormalization (ZPR), which arises through interaction with the zero-

point motion of nuclei.

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QUANTUM RENORMALIZATION OF THE BAND GAP OF SEMICONDUCTORS BY

ELECTRON-PHONON INTERACTION USING FIRST-PRINCIPLES CALCULATIONS

SUBMITTED POSTERS


In the last decade, extremely efficient first-principles methods have been developed to tackle the calculation of elec-

tron-phonon interaction. Using density-functional perturbation theory (DFPT), we evaluate the ZPR for 13 materials

and demonstrate that this renormalization is essential to obtain accurate first-principles predictions of the band gap.

We also present an application of this methodology to the pressure-induced topological phase transition in Rashba

semiconductor BiTeI. By tracking both the pressure and temperature dependence of the band gap, we show how the

critical pressure at which the material turns into a topological insulator evolves with temperature, thus providing an

guideline for experimental detection of this phase.

Véronique Brousseau-Couture, cont. Université de Montréal

QUANTUM RENORMALIZATION OF THE BAND GAP OF SEMICONDUCTORS BY

ELECTRON-PHONON INTERACTION USING FIRST-PRINCIPLES CALCULATIONS

Leah Cicon University of Victoria

A challenge of radiation therapy in cancer treatment is to effectively deliver therapeutic doses to tumours without

harming healthy tissue. Use of high atomic number nanomaterials such as gold nanoparticles (GNPs) are being exten-

sively researched and tested to act as local radiation dose enhancers. Due to the `leaky vasculature' present in a tu-

mour environment, GNPs of sub-100 nm diameter can penetrate through the extra cellular matrix of the tumour

and be internalized by the cells. The effectiveness of GNP treatments relies on optimizing the uptake of nanoparticles

into the cells.

There has been research done evaluating uptake of GNPs in monolayer cell samples, however monolayer samples

are a simplification of a real tumour like environment. Therefore, the focus of this research is to grow three dimen-

sional multilayer tumour spheroids as better approximations to real tumours and investigate GNP uptake through

the tissue structures and to compare to a monolayer (two dimensional) tissue model.

We were successful in growing a 3D in vitro tissue model to investigate uptake and transport of GNPs of various

sizes in tissue like materials. Our models morphology was found to be consistent with prior in vivo experimentation.

Hence, we believe that developing these 3D tissue models can help bridge the gap between in vitro and in vivo ex-

perimentation and optimize GNP use for future cancer therapeutic applications.

GOLD NANOPARTICLES IN CANCER THERAPEUTICS

SUBMITTED POSTERS


In anticipation of the Canadian Long Range Plan 2020 (LRP2020) call for white papers on issues relating to equity,

diversity, and inclusion in the field of astronomy, we have begun the process of collecting demographic information

for the undergraduate, graduate, and faculty population of the Physics Department at McGill University (where the

Astrophysics program is housed).

We will present our current dataset, which includes self-identified, binary gender information for both applicants and

registered students between the years of 2002 and 2018 (N>5000). This dataset provides a powerful tool for quanti-

tatively assessing the status of women in the department over time, and for guiding internal department initiatives to

foster greater inclusivity and diversity. Standardizing metrics and coordinating methods for collecting data about di-

versity will allow for measurement of progress over time within departments, as well as comparisons across depart-

ments to better assess the state of the field. For LRP2020, we hope to expand this work to include institutions

across Quebec and Canada, with the ultimate goal of improving the climate for women and underrepresented minor-

ities in astronomy at the national level.

Carolina Cruz-Vinaccia McGill University

Ruth Digby University of Victoria

Dwarf galaxies, those galaxies which are hundreds or thousands of times smaller than the Milky Way, are powerful

tools in the study of galactic evolution. As the most numerous class of galaxies in the universe, they probe a diverse

range of environments: some evolve in near-complete isolation, allowing us to measure how a galaxy’s evolution de-

pends on its intrinsic properties without needing to disentangle the effects of external forces. Others have been ac-

creted by larger galaxies and demonstrate the impacts of environmental processes such as tidal stripping. Because

dwarf galaxies are very small, and therefore have shallow potential wells, these internal and external processes leave

strong signatures in the galaxies’ star formation histories (SFHs).

Cosmological simulations allow us to follow individual galaxies through time, and to measure SFHs to arbitrary preci-

sion, an extremely challenging task for observations of real galaxies. By combining data on the lifetime evolution of

dwarf galaxies with signatures in their SFHs, such as trends with stellar mass (internal drivers) and environment

(external drivers), we can identify what processes determine a galaxy’s evolution and final characteristics. I will pre-

sent results from the APOSTLE and Auriga simulations, along with analysis of Local Group observations, which to-

gether provide a clear picture of the physics governing dwarf galaxy evolution.

DWARF GALAXY EVOLUTION FROM COSMOLOGICAL SIMULATIONS

A DATA-DRIVEN APPROACH TO ASSESSING AND INCREASING DIVERSITY AND

INCLUSIVITY IN CANADIAN ASTROPHYSICS: A FIRST STEP AND A CALL FOR PARTNERS

SUBMITTED POSTERS


Nitrogen oxides (NOx) in the stratosphere are produced by N2O, which is the dominant emission contributing to

stratospheric ozone depletion in the 21st century. Decades worth of observations are required in order to quantify

the variability and trends in stratospheric NOx so that we can better understand their impact on climate. The Strato-

spheric Aerosol and Gas Experiment (SAGE) II was a solar occultation instrument that measured NO2 from 1984 to

2005, while the Optical Spectrograph and InfraRed Imager System (OSIRIS) is a limb scattering instrument that began

measuring NO2 in 2001. By taking advantage of the four year overlap between these instruments it was possible to

produce a merged dataset of stratospheric NO2, spanning over 34 years. In order to merge the data a photochemi-

cal correction was applied to account for the different times of day at which the instruments measure, and to con-

vert the NO2 to NOx. A linear regression model was applied to the merged dataset to determine the trend. The

dominant source of variability in the mid-stratosphere tropics is the quasi-biennial oscillation, while aerosol is the

largest source of variability in the lower stratosphere. After accounting for these natural sources of variability an in-

crease in NOx of 16% per decade was observed in the tropical stratosphere near 22 km. Results are comparable to

those from the Whole Atmosphere Community Climate Model (WACCM).

Kimberlee Dubé University of Saskatchewan

Olivia Ellis University of Ottawa

Generally, humans do not enjoy unpleasantness. When we hear a very unpleasant (dissonant) sound, we will either

try to avoid that sound, or modify it to make it sound more pleasant (consonant). But what exactly is happening in

our brains that makes us perceives a pleasant or unpleasant sound?

Luckily, this topic in physics is hardly new. Scientists and mathematicians have tried to answer this age-old question

for more than 200 years. For example, Pythagoras and Helmholtz have proposed the frequency ratio theory and the

beating harmonics theory, respectively, to attempt to explain musical consonance and dissonance. One very signifi-

cant paper, written by Inbal Shapira Lots and Lewi Stone in 2008, not only compares the two theories, but also stud-

ies dyads (two pure tones played together simultaneously) to explain pitch perception. They concluded that the con-

sonance of a dyad was directly related to the firing patterns our neurons make. To illustrate this idea, they described

the system as "two coupled 'integrate-and-fire' neural oscillators", where they solved simple first-order differential

equations. A fascinating result from this is "The Devil's Staircase", and at each "step", a ratio of the dyad frequencies

is found.

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MUSICAL CONSONANCE AND DISSONANCE

TRENDS IN STRATOSPHERIC NOX OBSERVED BY SAGE II AND OSIRIS

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Surprisingly, humans are not the only living species that reflexively avoid dissonant sounds. Electric fish have also

been known to change sounds to make them more consonant. If a nearby fish is producing a frequency that causes

interference with another nearby fish, they will alter their natural discharge frequencies to decrease the beats that

are occurring between them.

Not only is it important to understand the process of how we perceive consonant and dissonant sounds, but it is

also important to realize how prevalent pitch perception is in our everyday lives.

Olivia Ellis, cont. University of Ottawa

Andrea Fodor McGill University

Belle II is a next-generation B-factory particle physics experiment located at the SuperKEKB e−e+ collider, with a

focus on examining the decays of B-meson pairs. The collider is energy-asymmetric, with a planned record-breaking

instantaneous luminosity of 8×10^35 cm^(−2)s^(−1), 50 times that of its predecessor, KEKB. This will enable Belle II

to gather 30 times more data than both previous-generation B-factories, Belle and BaBar, combined.

With the increase in luminosity comes an increase in beam backgrounds. Beam backgrounds lower the detection

precision and can damage the sensitive detector elements. The background profile needs to be thoroughly examined

in the new and uncharted high-luminosity environment of Belle II. In this presentation, I will go over the main back-

ground types encountered in B-factories, their effects and methods implemented for their reduction. I will focus on

the background rates seen by the electromagnetic calorimeter, the sub-detector used to measure the energy of elec-

trons and photons.

BACKGROUND ENVIRONMENT IN THE BELLE II EXPERIMENT AND ESTIMATION OF

BACKGROUND RATES IN THE ELECTROMAGNETIC CALORIMETER

MUSICAL CONSONANCE AND DISSONANCE

SUBMITTED POSTERS


As dark matter detectors grow larger and more efficient, neutrinos from the sun and other astrophysical sources

become a significant background. If predictions hold true, the next generation of detectors is set to reach the neutri-

no floor. The neutrino floor typically shown in papers was computed specifically for an ideal Xenon scintillator detec-

tor, using a Maxwellian speed distribution for the dark matter in the Milky Way. Although this represents a good es-

timation, it is of insufficient precision when good predictions for specific experiments are needed. In this work, the

objective is two-fold. We first study the impact of detector properties on the neutrino floor. We then show how

uncertainties on the distribution of dark matter in our vicinity impacts predictions.

We first computed the neutrino floor for currently proposed future Xenon TPC and Argon single-phase dark matter

detectors. We include the impact of neutrino-electron scattering and show that Argon detectors have a significantly

lower neutrino floor for higher dark matter particle masses. We also computed the impact of a potential anisotropy

in the dark matter distribution and show that it has a negligible impact on the interpretation of future experimental

results. We finally discuss how a more precise knowledge of neutrino fluxes on earth could potentially push the neu-

trino floor limit lower.

Andrea Gaspert Université de Montréal

Mariola Goga Polytechnic University of Tirana

Natural radioelements, like uranium and thorium decay chains and potassium radioelement are treated in details

since they are the main origin of NORM. Of interest to this study is oil-holder areas of Vlora-Elbasan, therefore a

brief description of the geology of the area that includes the oilfields of Kuçova, Ballësh Ballsh-Hekal and Marinez is

included. Generally, radioelements of uranium and thorium are present in rock formations. Formation water contains

radioactive elements, constituents of the decay chain of 238U and 232Th, respectively 226Ra, 224Ra and 228Ra, the

three radioisotope of radium. The radiological implications of oil extraction industry closely dependent on the type

of geological traps (type of rock formation in which the oil is accumulated) and the techniques used to extract the

oil. For this reason it is done a bibliographic treatment to describe the origins and characteristics of radioactivity in

oil industry. The object is to identify the health and environmental impact of oil extraction industry in Albania. The

concentration of radionuclides in produced water and crude oil were found to be minimum detectable activities.

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EVALUATION OF NATURAL RADIOACTIVITY IN THE LAND IN THE MAIN-DISTRIBUTIVE

PETROLEUM FIELDS IN ALBANIA

ON THE NEUTRINO FLOOR FOR THE NEXT GENERATION OF LIQUID NOBLE DARK

MATTER EXPERIMENTS

SUBMITTED POSTERS


From the radiological point of view, the excess of annual effective dose rate from industrial residues was estimated

to be much lower than the recommended limits for population and workers. In conclusion, human and environmen-

tal impact of the oil industry in Albania is negligible from radiological point of view.

Key words: Evironmental radioactivity, Oil extraction industry, HPGe gamma-ray spectrometry, Industrial waste/by-

product, Radionuclides 238U, 232Th and 40K, Dose rate assessment

Mariola Goga, cont. Polytechnic University of Tirana

Prashansa Gupta Université de Montréal

A considerable amount of progress has already been made in our understanding of exoplanet atmospheres by meas-

uring transmission, thermal emission and phase curves for a variety of hot Jupiters. However, several open questions

remain in the understanding of their albedos, the most fundamental being the hot Jupiter Albedo problem. While So-

lar System gas giants show Bond albedos lower than geometric albedos, the measurements from optical and infrared

instruments (Kepler, CoRoT, MOST and Spitzer) for hot Jupiters such as HD 189733 and HD 209458 show the op-

posite. This phenomenon could be explained by higher geometric albedos at UV/optical wavelengths outside the

Kepler bandpass, but very few measurements exist to corroborate this. We present the first multiple HST/STIS re-

flection spectra for a well-characterized hot Jupiter WASP-43 b in the 290-570 nm waveband, and provide limits on

the geometric albedo. When combined with the existing Spitzer or improved JWST’s eclipse observations at wave-

lengths > 600 nm, these observations will answer key questions about its atmospheric composition, structure, global

energy budget and circulation.

FIRST MULTIPLE HST/STIS ECLIPSE OBSERVATIONS OF WASP 43 B

EVALUATION OF NATURAL RADIOACTIVITY IN THE LAND IN THE MAIN-

DISTRIBUTIVE PETROLEUM FIELDS IN ALBANIA

SUBMITTED POSTERS


The last century has seen exciting tests of general relativity and the LIGO-Virgo observatories have now definitively

discovered black holes. And yet we are only beginning to approach the event horizon with electromagnetic observa-

tions. Sagittarius A* and M87 are two of the closest supermassive black holes targeted by the Chandra X-ray Obser-

vatory, as well as VLT's GRAVITY instrument, the Event Horizon Telescope, and many more. They offer an exciting

opportunity for coordinated, multi-wavelength campaigns, which are poised to identify the origin of observed X-ray

and IR variability, connect it to horizon-scale structure in the submm, and distinguish between competing models: hot

spots, inflow/outflow, reconnection regions, shocks, or even magnetosphere gaps. I will present highlights from

Chandra and multi-wavelength observations of Sgr A* and M87 and prospects for future discovery.

Daryl Haggard McGill University

The Women in Physics Committee at McGill University pursues a range of inreach and outreach activities to support

equity and inclusion in STEM. This poster will outline our efforts to offer equity resources and education for our fac-

ulty, staff, and students, as well as outreach workshops/panels in our local Cégep communities.

EVENT HORIZON DYNAMICS: X-RAY AND MULTI-WAVELENGTH VARIABILITY OF SGR

A* AND M87

WOMEN IN PHYSICS COMMITTEE AT MCGILL UNIVERSITY

Ksenia Kolosova McGill University

Rabbits are frequently used for testing injectable biomaterial and tissue engineering treatments for vocal fold scarring.

In these studies, treatment effectiveness is most often evaluated by tissue slicing followed by histological or immuno-

histochemical staining. Cutting the tissue into thin slices prohibits subsequent application of other types of analysis

and can introduce artifacts such as deformation. In response to these limitations, three-dimensional virtual histology

approaches can be used to acquire volumetric data and extract high-resolution information from any plane of inter-

est in intact tissue. These methods include (micro/nano)computed tomography (CT), magnetic resonance imaging

(MRI), and microscopy image stacks. Nonlinear laser-scanning microscopy (NM) is a desirable virtual histology meth-

od for studying scarring because it directly visualizes second harmonic generation signal from fibrillar collagen and

autofluorescence from elastin fibers, two important players in wound healing whose distribution and organization

facilitate diagnosis of scar formation and severity. This method however necessitates long scan times and requires

small specimen sizes due to a penetration depth limitation, obliging precise injury localization prior to dissection. This

motivates the use of lower-resolution, faster scanning time approaches that accommodate larger specimens, such as

MRI and CT, for acquisition of first-pass images. These can reveal larger-scale patterns, serve as platforms for com-

puter model creation, and inform targeted dissection of samples for NM.

CHARACTERIZING VOCAL FOLD INJURY RECOVERY IN A RABBIT MODEL WITH

MULTIMODAL IMAGING

SUBMITTED POSTERS


We investigated the effects of teaching strategies and environmental factors in a first-year electromagnetism course

by testing students' learning outcomes using an online system, the McGill Learning Platform (McLEAP). We will pre-

sent some of our most instructive findings based on over 1000 students spanning three years, in terms of content

sequencing, group work, use of external and online resources, gender, origin, and self-reported math ability. We find

that content sequencing has a significant impact on learning outcome; specifically, students presented with conceptual

content first perform significantly better on our assessment than those first learning from a theoretical approach.

Additionally, we find that instructors’ preferences for content sequencing differ significantly from students’. We also

explore the interconnections among environmental factors, and their impact on performance. We will discuss how

this information can be used to improve course instruction and student learning.

Ksenia Kolosova McGill University

Yi-Hsuan "Cindy" Lin SNOLAB

The SNO+ experiment is a multi-purpose neutrino physics detector located 2 km underground in SNOLAB

(Sudbury, Ontario). The centerpiece of SNO+ is a 12-m diameter acrylic vessel, containing the detection medium

liquid. The acrylic vessel is surrounded by 7 kilotonnes of ultrapure water shielding and about 9500 photomultiplier

tubes. SNO+ will operate in three phases: water, scintillator, and scintillator with Te-130 loading. To understand the

detector response and performance, a variety of calibration techniques are employed. An AmBe source, originally

used by the SNO experiment, is used for neutron calibrations. A new scintillator-compatible encapsulation needs to

be designed for upcoming phases to ensure material compatibility and to shield the low energy xrays originating from

the source. SNO+ detects reactor antineutrinos and geo-antineutrinos via inverse beta decay. Neutron calibration

will inform physics analyses such as the antineutrino search. Both the design for the new encapsulation and the po-

tential for antineutrino search will be discussed.

ANTINEUTRINO SEARCH IN SNO+

CONTENT SEQUENCING AND ENVIRONMENTAL FACTORS FOR IMPROVING

LEARNING IN LARGE FIRST-YEAR PHYSICS CLASSES

SUBMITTED POSTERS


By combining analysis conducted using simplified toy models, full blown GCMs, and ultimately real data, we aim to

explore the limits of what atmospheric conditions are detectable in the spectra of hot Jupiters. Given that multiple

molecular species, including H2O and CO (Brogi et al. 2013), have already been robustly detected using high resolu-

tion spectroscopy (Birkby 2018), we seek to push these detections further by using high resolution spectra taken

during secondary eclipses to infer how these spectral lines may have been altered by the conditions under which they

were produced (e.g. their shape, depth) and use that to inform us about atmospheric characteristics. To do this, we

combine simplified toy models that demonstrate the scale of the effects of atmospheric conditions on spectral lines

with full blown GCMs capable of creating a more realistically complex portrait of what these effects might look like

in the resulting spectra we observe. This will inform our target selection and observational strategy to conduct fu-

ture observations using the SPIRou spectopolarimeter on the Canada-France-Hawaii telescope, as well as our ulti-

mate handling of the data to enable us to extract as much information as possible.

Melissa Marquette McGill University

Deniz Ölçek McGill University

I will give a brief update on the status of the Hydrogen Intensity and Real-time analysis eXperiment (HIRAX) which is

a 1024 element radio array currently under development in the Karoo desert, in South Africa, aiming to map 21-cm

intensity in the Southern Sky. The primary science goal of this experiment is to investigate one of the greatest puz-

zles facing the contemporary cosmology, namely the dark energy, which occupies 70% of the universe’s content and

is responsible for the accelerated expansion of the universe. Currently the commissioning of the 8-element pathfind-

er is continuing and the construction of HIRAX-128 will start late this year. The instrument will operate between

400-800 MHz and will be CHIME’s “southern sister experiment”, sharing essentially the similar science goals.

STATUS OF THE HIRAX ARRAY

CHARACTERIZING EXOPLANETS WITH HIGH RESOLUTION SPECTROSCOPY ECLIPSE

MAPPING

SUBMITTED POSTERS


In physics, the Lagrangian constitutes a simple, all-encompassing tool that allows us to describe and analyze any sys-

tem’s mechanics. However, it is quite abstract and hard to visualize, unlike the classical Newtonian method. My talk

will focus on a possible solution to this. Namely, I will propose to advance our physical intuition of this quantity, and

its evolution in time, through dance. More specifically, I will introduce a framework in which it would be possible to

translate any system’s Lagrangian into human motion. The first step is to quantify human movement. To do so, I plan

on presenting algorithms recently developed by a team at the University of Waterloo quantifying the four character-

istics of motion as defined by Rudolf von Laban in his well-known taxonomy of dance. The next step is to solve for a

dimensionally correct vector that, when multiplied by the matrix composed of the motion algorithms, gives us the

kinetic and potential energies of the motion, as it is defined by the matrix. My talk will thus guide the audience

through a rather simple reasoning process that connects human motion to the dynamics of any system in the Uni-

verse. If made possible by the space, a dancer would then demonstrate the human motion of a system with a simple

Lagrangian time-wise evolution. I would thereafter invite the audience to take a step back and consider how we can

use dance to not only contribute to our understanding of physics but also make it more accessible. These two com-

munities, both rather misunderstood by the public, share an overarching goal of studying motion and time: we can

use that. I wish to leave attendees more aware of the power of an interdisciplinary collaboration such as this one,

and possibly inspired to create one of their own.

Mathilde Papillon McGill University

Stefan Pelletier Université de Montréal

Characterising the atmosphere of a planet outside of our Solar System is something that humans only dreamed of

barely two decades ago. Today, mostly through pioneer advancements by the Spitzer and Hubble Space Telescopes,

this has not only become a reality, but a booming and prominent field of research. Although not having to observe

through the Earth’s atmosphere is great, one caveat of space-based observatories is the intrinsic low spectral resolu-

tion of the instruments they cary. For exoplanet atmosphere characterisation, this unfortunately means that detect-

ing molecules can only be done from broad molecular bands which often yield highly degenerate solutions. Over the

last decade, the development of ground-based much higher resolution infrared detectors has allowed us to circum-

vent this problem and provide strong unambiguous detections of molecules in exoplanet atmospheres.

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SPIROU & NIRPS: CANADA’S ENTRANCE TO THE STAGE OF EXOPLANET

ATMOSPHERES CHARACTERISATION USING HIGH-RESOLUTION INSTRUMENTS

DANCING THE LAGRANGIAN:

UNDERSTANDING MECHANICS THROUGH HUMAN MOTION

SUBMITTED POSTERS


Now with the arrival of SPIRou at the Canada France Hawaii Telescope and soon NIRPS at the La Silla Observatory,

Canada will be entering the very promising ground-based near-infrared high-resolution stage with two of the most

powerful instruments currently available in the world. In this talk I will present some of the very first results obtained

with SPIRou as well as discuss the many things we hope to achieve in the next few years with these instruments.

Stefan Pelletier, cont. Université de Montréal

Myriam Prasow-Émond Université de Montréal

Le taux de formation d'étoiles dans les amas de galaxies (de type "cool core") les plus extrêmes est censé atteindre

plusieurs milliers de masses solaires par année. Toutefois, il est maintenant connu que l'AGN (Active Galactic Nucle-

us) réchauffe le milieu intergalactique, ce qui abaisse considérablement le taux de formation d'étoiles. L'énergie est

injectée via des jets relativistes qui créent de géantes cavités visibles dans les rayons X. Dans cette présentation, on

introduit MACS J1447.4 + 0827, l'un des amas "cool core" les plus extrêmes et puissants jamais découverts et récem-

ment observé par Chandra, HST et JVLA. Nous allons présenter ces nouvelles données ainsi que les structures fas-

cinantes de l'amas, telles que les jets relativistes, les mini-halos, les filaments ainsi que la plume.

SPIROU & NIRPS: CANADA’S ENTRANCE TO THE STAGE OF EXOPLANET

ATMOSPHERES CHARACTERISATION USING HIGH-RESOLUTION INSTRUMENTS.

L'EFFET FASCINANT DU TROU NOIR SUPERMASSIF AU CENTRE DE L'AMAS MACS

J1447.4 + 0827

SUBMITTED POSTERS


Machine learning algorithms are sensitive to meaningless (or "adversarial") perturbations. This is reminiscent of cellu-

lar decision-making where ligands (called "antagonists") prevent correct signaling, like in early immune recognition. In

this talk, I will draw a formal analogy between neural networks used in machine learning and models of cellular deci-

sion-making (adaptive proofreading). I will highlight how robust adaptive proofreading models have evolved, and how

the absence and presence of a critical point allows us to distinguish between regimes of robust and nonrobust classi-

fication. With this, we can set conditions that neural networks robust to adversarial perturbations should satisfy, i.e.

by having shallow decision boundary around the classes, and steep decision boundaries between the classes.

Thomas Rademaker McGill University

Annabelle Richard-Laferrière Université de Montréal

Massive black holes play an important role in the formation of galaxies, likely modulating the growth of the stellar

component. Indeed, there is an observed correlation between the mass of the central black hole (MBH) and the

bulge stellar velocity dispersion (σ) in a galaxy. Our understanding of this fundamental relation is still incomplete,

even if it is extensively used to support models of the linked formation of galaxies and black holes. Furthermore,

there is a deviation from the relation at low-mass and a lack of experimental data at the high-mass end. Indeed, there

are only four black holes with masses exceeding 1010 Mʘ (solar masses) known so far. Finding new black holes of

more than 1010 Mʘ is therefore the only way forward to understand the details of the MBH-σ relation and confirm

or infirm the deviation at high-mass. We have identified an exceptional galaxy, PKS 0745-BCG (z=0.1028), which

should be at least 2.5 × 1010 Mʘ, but could be the first 1011 Mʘ black hole ever measured. By targeting the most

massive black hole in the Universe, the deviation of the MBH-σ relation should be most evident and allow to draw

more conclusions on the curve of the relation. I will explain why we think this black hole could be the most massive

one in the Universe and how we are trying to find its mass using new Hubble Space Telescope data of the gas around

the black hole. Furthermore, I will explain how this method is now confirmed thanks to the new image of M87 taken

by the Event Horizon Telescope Collaboration.

ATTACK AND DEFENCE IN CELLULAR DECISION-MAKING:

LESSONS FROM MACHINE LEARNING

MEASURING THE MASS OF PKS 0745-191, ONE OF THE MOST MASSIVE BLACK

HOLES IN THE UNIVERSE USING HUBBLE SPACE TELESCOPE DATA

SUBMITTED POSTERS


Spin qubits are a promising architecture for quantum computers due to their long coherence time and compatibility

with industrial fabrication techniques. However, scalability issues arise when trying to create a system with many

qubits. The more qubits there are, the more time it takes to initialize the system in the desired configuration and the

more equipment is needed to control each quantum dot. Therefore, a scalable qubit control system addressing both

these issues is presented. By using a Field Programmable Gate Array (FPGA) based system, it is possible to greatly

accelerate device characterization while being relatively compact. The FPGA system can be several orders of magni-

tude faster than typical apparatus allowing for real-time measurements.

Marc-Antoine Roux Université de Sherbrooke

Laura Saunders University of Toronto

The Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) is a Canadian satellite instru-

ment that measures over 40 trace gases in the Earth’s atmosphere using infrared spectroscopy. It has taken up to 30

measurements per day since 2004, compiling a global data set that contains tens of thousands of profiles from the

cloud-tops to the lower thermosphere. ACE-FTS data are therefore extremely useful for detecting trends in atmos-

pheric composition so that they can be more directly linked to anthropogenic activity. One of the gases that it

measures is CFC-11, an ozone-depleting substance whose concentrations have been decreasing since the early 1990s

due to the 1987 Montreal Protocol and its subsequent amendments. Recently, however, ground-based measure-

ments found that CFC-11 was no longer declining as quickly as expected near the Earth’s surface. In this work, we

used ACE-FTS data and chemical transport model output to examine whether this change could be detected in the

stratosphere, where the ozone layer is located.

FAST TUNING OF QUANTUM DOTS USING FPGAS

DETECTING CHANGES IN CFC-11 TRENDS NEAR THE OZONE LAYER

SUBMITTED POSTERS


I will be discussing some phenomena that arise when we consider Spin-Orbit (S-O) coupling (of two kinds - Kane-

Mele and Rashba) in Graphene. Such a system has robust chiral edge modes. Adding a periodic array of potential bar-

riers modifies the spectrum of S-O coupled graphene. I will talk about the combined effect of S-O couplings and peri-

odic potentials on the propagation of wave packets, focusing on the special case when the strengths of the Kane-

Mele and Rashba S-O couplings are equal. The propagation of wave packet in presence of periodic potentials will also

be discussed.

Ranjani Seshadri McGill University

Meri Zaimi Université de Montréal

Qubits, which may be described as two-level systems, are the fundamental building blocks of quantum computers. An

undesired effect that occurs in realistic quantum systems is the loss of quantum information. This is a consequence of

the decoherence of quantum states due to the interaction with the environment. Topological states have properties

that protect them from noise and disorder, which makes them interesting for quantum computers. However, these

states are experimentally difficult to detect. We consider here the dynamics of a two-level system coupled to a finite

chain described by the Su-Schrieffer-Heeger (SSH) model. In the SSH model, only nearest neighbors are coupled, and

the hopping amplitudes alternate periodically between two values. This model has 0, 1 or 2 edge states, depending on

whether the number of sites of the chain is even or odd, and depending on the ratio of the hopping parameters. The

decoherence rate of the qubit has a strong dependence on the parity of the chain length. Thus, it should be possible

to detect topological edge states using the dynamics of a qubit.

SPIN-ORBIT COUPLING IN GRAPHENE - WAVE PACKET DYNAMICS

DETECTING TOPOLOGICAL EDGE STATES WITH THE DYNAMICS OF A QUBIT

SUBMITTED POSTERS


Printable electronics (PE) allow for the low-cost fabrication and high-volume production of customized electronic

devices; this makes PE appealing to a broad range of industries. Nowadays, the conductivity of PE devices is

generally controlled by destructive methods, e.g. four-point probes.

Therefore, the development of a fast, non-destructive, and contactless characterization tool is highly anticipated.

Since the spatial resolution of typical PE fabrication techniques is on the order of a few micrometers, resonant met-

amaterial structures with resonant frequencies in the terahertz range can be readily printed. Terahertz time-domain

spectroscopy (THz-TDS) is a powerful non-contact technique with sub-picosecond time resolution that provides

unprecedented insight into the nature of charge carrier dynamics in semiconductors. We designed and printed a set

of quality control patterns (QCP) with a frequency response of 0.22 THz and changed their conductivities by varying

the sintering parameters. To characterize resonance response of QCPs, we utilized standard THz-TDS. We experi-

mentally demonstrated, with appropriated calibration, that the transmission response of QCP as a function of the ink

conductivity is consistent with conventional conductivity measurements. Moreover, we show that THz-TDS has bet-

ter repeatability and precision; to follow the ink conductivity variability, than the conventional contact methods. Our

results show that THz-TDS is a suitable method for non-destructive and non-contact evaluation of PE devices, and

opens the door for in-situ quality control of PE manufacturing.

Mariia Zhuldybina École de Technologie Supérieure

QUALITY CONTROL OF PRINTED ELECTRONIC DEVICES

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SUBMITTED POSTERS Rajni Bagga - McGill Physics · 2019-08-09 · SUBMITTED POSTERS June 25-28, 2019 McGill University, Montréal, QC In the last decade, extremely efficient first-principles