Very recently, we have demonstrated femtosecond electron emission from metal nanotips when illuminated by THz light pulses, where electron bursts are ejected by sub-cycle light field emission. In the new CFI-funded Quantum Dynamics Laboratory, we are now building a new type of time-resolved electron microscope using these electrons based on the principle of point-projection. Central to this effort is the design and assembly of a new ultra-high vacuum (UHV) system, testing of its components and integration into the optical system providing intense THz pulses.

The student will be responsible for the assembly and testing of the custom-built ultra-high vacuum system, supervised by the professor and working in a team of graduate students and research technicians. Detailed technical documentation will be required for the assembly and testing of the UHV system. The student will be fully integrated into the group, with weekly one-on-one meetings, weekly group meetings with graduate students, and technical workshops related to ultrafast THz research and other career building workshops as part of an NSERC CREATE program TrUST.

The quality of research training provided in this project will be world class. The student will be involved in the building of a state-of-the-art instrument pushing the limits of spatial and temporal resolution. They will be heavily involved in the commissioning of a $6.4M research facility from the ground up, providing a truly unique training experience that only a handful of students will ever experience.

For more information contact: David Cooke (dave dot cooke at mcgill dot ca).

Posted on 2025/01/18

Recent years have seen the development at McGill of an exciting class of models coined phase field crystal (PFC) models that couple the thermodynamics that drive the formation of solids during non-equilibrium phase transformations to atomic-scale elasticity and plasticity that gives rise to complex defect microstructures that control the emergent properties of most materials. This is particularly prevalent during rapid solidification of critical metals such as tungsten and aluminum under rapid laser heating, a process at the heart of modern 3D metal printing. The Intern will work with a PhD student in the Computational Materials Science Group of Professor Provatas to use a PFC model for solidification to elucidate how the competition of kinetic and surface energy anisotropy and thermodynamic driving forces affect transitions between cellular to dendritic to hyper-branched morphologies in crystallized microstructures during rapid solidification. Select morphologies that emerge from simulations will also be examined analytically to determine the stability space of the PFC model’s parameter space

The student will learn to simulate numerical models with high performing computing and use it to simulate crystal structure data over a range of material parameter and cooling rates. They will then use both numerical and mathematical analysis to characterize the phase space of morphological patterns that emerge. Student will gain knowledge in computational physics, thermal physics, linear stability analysis, and materials science. They will be supervised by N. Provatas, mentored and one of Prof. Provatas’ senior PhD students, and co-supervised by Professor Jason Bramburger, in the Department of Mathematics and Statistics at Concordia University.

For more information contact: Nikolas Provatas (provatas at physics dot mcgill dot ca).

Posted on 2025/02/08

Single molecule nanofluidic technologies would benefit greatly from increased capacity to gain in situ control of confined analytes and allow rapid time modulation of confinement.  We have recently demonstrated a new type of nanofluidic technology (“electrokinetic confinement”) that performs single molecule capture, confinement and manipulation using free energy landscapes derived from nanopatterned AC electric fields via the electrokinetic forces induced on charged analytes. This approach enables on/off modulation of the confinement, so analytes can be repeatedly captured from solution, confined and released for high throughout and repeatable measurement.  In detail, in this project the student will use the technique to confine nanostructures made through DNA self-assembly (DNA nanotubes), perform measurement of molecular properties of trapped tubes and ultimately perform directed self-assembly within the electrokinetic traps.

The student will learn how to perform electrokinetic confinement experiments on Reisner lab fluorescence microscopy platforms.  This training includes chain staining protocols, nanofluidic device and microscope operation.  The student will then develop automated analysis routines in either Matlab or python to extract key qualities from the videomicroscopy data.  The student will be supervised in the lab by a PhD student and meet with Prof. Reisner on a weekly basis.

For more information contact: Walter Reisner (reisner at physics dot mcgill dot ca).

Posted on 2025/01/28

Cosmic Dawn (the period in our cosmic history when first-generation stars and galaxies were formed) remains a mystery. In the next few years, we may make the first direct observations of Cosmic Dawn through faint 21 cm wavelength radio waves. Making sense of these observations requires the existence of theoretical models to compare to. Unfortunately, these models often require computationally heavy simulations, which makes parameter space explorations difficult. In this project, we will run a set of reference simulations and extract observable quantities. We will then find parametric fits to these quantities using automated symbolic regression packages from the machine learning community. This will provide a handy set of formulae that can be used to speed up theoretical work for future parameter space explorations.

For this work, the plan is to use the semi-numerical code 21cmFAST. The student will first go through the code and run it to produce a library of predictions for observable power spectra. The student will then set up a symbolic regression package to fit the resulting library, delivering a set of analytical formulae to capture the behaviour of 21cmFAST.

The student will be a full member of our research group led by Dr. Adrian Liu and will therefore experience the full cycle of scientific research. They will attend weekly group meetings, 1-on-1 meetings, and weekly hack sessions with other group members. They will report back bi-weekly about the progress. They will be able to participate in the Trottier Space Institute Summer Program, where there will be weekly workshops on professional development and research skills.

For more information contact: Adrian Liu (acliu at physics dot mcgill dot ca).

Posted on 2025/01/28

In the next few years, the Canadian Hydrogen Observatory and Radio-transient Detector (CHORD) will individually identify a large number of hydrogen-rich galaxies. These galaxies will be primarily identified through their radio emission at 21cm wavelength. In detail, though, one finds that the radio emission is not precisely at 21cm wavelength. Instead, it has a narrow (but measurable) profile. In this project, we will correlate the properties of known galaxies with their emission profiles. Using techniques from both traditional statistics and machine learning, we will attempt to find relationships between various profile shapes and interesting galaxy properties. This will aid future categorizations of CHORD-detected galaxies, guiding decision-making for follow-up observations.

The student will first familiarize themselves with typical radio emission profiles from catalogs of hydrogen-rich galaxies. They will then experiment with ways to discretize the profiles. Next, we will attempt to fit linear models to the relation between profiles and galaxies before proceeding to fully non-linear models drawn from the statistics and machine learning literature.

The student will be a full member of our research group led by Dr. Adrian Liu and will therefore experience the full cycle of scientific research. They will attend weekly group meetings, 1-on-1 meetings, and weekly hack sessions with other group members. They will report back bi-weekly about the progress. They will be able to participate in the Trottier Space Institute Summer Program, where there will be weekly workshops on professional development and research skills.

For more information contact: Adrian Liu (acliu at physics dot mcgill dot ca).

Posted on 2025/01/28

Large arrays of radio telescope (such as the Hydrogen Epoch of Reionization Array, HERA, or the Canadian Hydrogen Observatory and Radio transient Detector, CHORD) are currently attempting to map our Universe using sensitive measurements of faint radio waves. Unfortunately, there exist strong sources of radio frequency interference (RFI) that contaminate our measurements. Examples of RFI include radio stations, digital TV, and other radio transmitters. Because RFI signals are so strong, the traditional approach has been to simply discard data that is RFI-contaminated. This project targets a more ambitious goal: to try to mathematically model the probability distributions that govern RFI. We will begin by looking at empirical RFI data from the Murchison Widefield Array (MWA). This will provide a first look at the probability distributions that we will then characterize mathematically. Time-permitting, we will explore how this knowledge can be folded into statistically disciplined analyses that incorporate automatic outlier analysis, or whether machine learning techniques can provide a more efficient way to model the probability distributions.

The student will be trained in handling observational data products from modern radio telescopes. They will gain intuition for these data by making diagnostic plots and computing summary statistics. For the automatic outlier analysis and the machine learning analyses, the student will learn to use state-of-the-art processing codes and apply them to our simulations and real data.

The student will be a full member of our research group led by Dr. Adrian Liu and will therefore experience the full cycle of scientific research. They will attend weekly group meetings, 1-on-1 meetings, and weekly hack sessions with other group members. They will report back bi-weekly about the progress. They will be able to participate in the Trottier Space Institute Summer Program, where there will be weekly workshops on professional development and research skills.

For more information contact: Adrian Liu (acliu at physics dot mcgill dot ca).

Posted on 2025/01/28

Defect centers in diamond have become a workhorse for quantum information science and quantum sensing thanks to their long-lived quantized spin states that can be prepared and detected optically, and manipulated with near-resonant microwaves. In particular, the spin of the nitrogen-vacancy (NV) center in diamond permits exquisitely sensitive quantum magnetometry both at the nanoscale and in macroscopic ensembles. Such experiments are typically realized in a bias field to isolate the different spin transitions and different defect orientations, which introduces an important source of inaccuracy associated with undetectable drifts in the bias field. Our research team seeks to get rid of the need for a bias field by instead isolating the different spin transitions and orientations using optimal control of the microwaves driving the defect spin. Initial experiments will be performed on individual defect centers to allow more detailed comparison with theory, requiring a setup capable of resolving single NV centers. This USRA project will build the confocal microscope needed to isolate and address individual NV centers, laying the groundwork for future optimal control experiments.

Individual atomic-scale defect centers can be isolated and addressed using confocal microscopy, which effectively rejects background fluorescence from other sources by imaging the emitted fluorescence onto an aperture. The USRA student will build a confocal microscope from scratch, including spatial and temporal control of the excitation laser, scanning capabilities, and single-photon-counting detection. Initially, they will model the propagation of the laser beam through the optical system, learning about Gaussian beam propagation in the paraxial limit, and identify appropriate components. They will set up and characterize a double-pass AOM system to modulate the laser on ~10 ns timescales and align a spatial filter to clean up the laser spatial mode. They will set up a scanning system using either a piezoelectric stage or a scanning mirror, learn to align a high-NA objective, and align the excitation and detection paths with few micro-radian precision. In addition to this extensive training in optics, they will update and potentially develop new features for control software to enable imaging with the confocal microscope. With the completed apparatus, they will characterize the images with test targets, and ultimately test their ability to resolve single defects in high purity diamond samples. If time allows, the student will incorporate MW excitation of the sample and use the confocal microscope to observe resonant driving of the NV spin transitions.

The student should have a taste for carrying out hands-on experimental work in a lab. To ensure hands-on supervision given PI travel constraints, this project will run from the end of April or very beginning of May ending no later than July 25th.

For more information contact: Lily Childress (childress at physics dot mcgill dot ca).

Posted on 2025/02/04

Genetically encodable fluorescent proteins such as green fluorescent protein (GFP) have revolutionized live cell biophysics and cell biology. However, the red fluorescent proteins (RFPs) have been more problematic, often lacking photostability and having lower brightness than their green counterparts. Moreover, the fluorescent proteins have generally been very poor fluorophores for Stimulated Emission Depletion (STED) super-resolution imaging methods. Bindels et al. (Nat. Methods 2017) reported the development of a new red fluorescent protein mScarlet that is brighter than other RFPs and can be used for STED super-resolution imaging.

In this project, the student will test a third generation mScarlet RFP for its imaging and photophysical properties in both standard resolution confocal laser scanning microscopy (CLSM) and super-resolution STED imaging. The mScarlet will be expressed with a surface protein (Lyn tyrosine kinase-mScarlet) in chemically fixed human embryonic kidney cells. The cells will be prepared by a graduate student. The USRA student will be trained to image the fixed cells on an Abberior STED system which can operate either in CLSM or STED imaging modes and trained in quantitative image analysis methods. The USRA student will systematically compare CLSM and STED optical resolution, photostability (via time series measurements of photobleaching), determine if there is emission blinking under a range of collection conditions (laser power for excitation and/or depletion, pixel dwell time, etc.). The goal will be to optimize the measurement conditions for super-resolution imaging of mScarlet in fixed cells. The student can expect to be trained in state of the art super-resolution imaging (nanoscopy), fluorescence methods, and quantitative image analysis and will have daily contact with Prof. Wiseman and a Physics PhD student.

For more information contact: Paul Wiseman (wiseman at physics dot mcgill dot ca).

Posted on 2025/02/04

What do climate change research and radio astronomy share in common?  Permafrost, or soil that remains frozen for at least two years, experiences increased thawing as global temperatures rise, threatening northern ecology and infrastructure.  The MIST radio astronomy experiment studies the first stars and galaxies from the high Arctic, and MIST's ground-based antenna is highly sensitive to the electromagnetic properties of the local soil environment, including permafrost.  We are seeking a student interested in fostering teamwork between geophysics and radio astronomy to develop a prototype of a non-invasive device for studying the dynamics of permafrost, involving instrument design, field testing, and data analysis.

The student who takes on this project will design and build a prototype of a permafrost monitoring system.  The instrument development, guided by lessons learned from MIST, will involve a combination of mechanical and electronics design.  The work may also involve developing logging software, and prototype testing and validation in the lab and at local field sites.  The work will be performed in a collaborative and interdisciplinary environment, with opportunities to interact with researchers from other institutions.

For more information contact: Cynthia Chiang (chiang at physics dot mcgill dot ca).

Posted on 2025/02/06

Measurements of the radio sky at ~100 MHz and below have the potential to open a new observational window in the universe's history.  At the lowest frequencies (tens of MHz), future observations may allow us to one day probe the cosmic "dark ages," an epoch that is unexplored to date.  Measurements at these frequencies are extremely challenging because of radio-frequency interference and ionospheric effects.  The state of the art among ground-based measurements dates from the 1960s, when Grote Reber caught brief glimpses of the ~2 MHz sky at low resolution.  The Array of Long Baseline Antennas for Taking Radio Observations from the Seventy-ninth parallel (ALBATROS) is a new experiment that aims to map the low-frequency sky using an array of autonomous antenna stations.  These antenna stations will observe independently, over long baselines, and will be interferometrically combined offline.  The array is under construction at the McGill Arctic Research Station on Axel Heiberg Island, a location that is exceptionally radio-quiet and has reduced ionospheric interference relative to lower-latitude sites.

The student who takes on this project will develop the hardware, electronics, and/or software that are needed for the autonomous antenna stations.  Possible areas of work include developing and testing calibration electronics, testing and integrating an upgraded readout system, improving remote communications with the antenna stations via Starlink, developing quicklook analysis tools, and field testing the antenna stations at Uapishka Station.  In addition to developing a broad spectrum of experimental skills, the student will also gain exposure to working within a multi-institution collaborative setting.

For more information contact: Cynthia Chiang (chiang at physics dot mcgill dot ca).

Posted on 2025/02/06

This project will focus on the development of a flexible drone-based calibration system that will be used for characterizing radio astronomy instruments.  Many radio astronomy experiments employ stationary telescopes (dishes or antennas) that are sited in remote locations.  One of the most important aspects of radio telescope characterization is the measurement of the spatial response on the sky, or the "beam pattern."  One solution to this measurement problem is flying a drone-mounted transmitting source over the telescope, and mapping the telescope's response.  Drones are also a promising platform for ground-penetrating radar (GPR) measurements, which characterize the electromagnetic properties of the ground that sits beneath radio telescopes.  These properties subtly impact on-sky telescope responses.

The student who takes on this project will have the opportunity to work on a variety of tasks related to the development of drone-based transmitters and GPR prototypes.  Possible areas of work include designing new antennas/transmitters for low-frequency operation, subsystem development and testing for a custom-built GPR, developing software tools for analyzing drone flight data, and participating in drone test flight campaigns both locally and at field sites (e.g., Uapishka Station and DRAO).

For more information contact: Cynthia Chiang (chiang at physics dot mcgill dot ca).

Posted on 2025/02/06

Upcoming radio telescopes such as the Canadian Hydrogen Observatory and Radio-Transient Detector (CHORD) and the Hydrogen Intensity and Real-time Analysis eXperiment (HIRAX) will be massively redundant arrays that will study cosmology. They will map out the evolution of dark energy when the universe was half its current age using the 21-cm line of neutral hydrogen. This signal is incredibly faint and may only be teased out of the noise after a great deal of averaging. In order to enable this averaging, the raw data must first be calibrated to remove the effects of the various electronics that the signal encounters as it propagates through the signal chain. Correlation Calibration, or CorrCal, is a novel calibration technique that simultaneously leverages the strengths and mitigates the shortcomings of commonly employed calibration techniques.

While the dishes in the arrays are all supposed to be exactly the same, in practice that is never true. In this project, the student will use CorrCal to measure imperfections in the arrays as part of the calibration process using simulated data. CorrCal should enable measuring where antennas actually are and where they are pointing, and provide quantitative error estimates of those positions. Calibrating large interferometric data sets is a rich and complex challenge, so the student should be prepared to learn a great deal of new material. The project will require working with and building on the CorrCal software stack, so some familiarity with Linux and a strong familiarity with Python are required.

The student will learn the relevant fundamentals of radio interferometry and calibration, and will have opportunities to learn about 21-cm cosmology. They will further develop their scientific programming skills and gain experience working with, and possibly developing, version controlled software in a collaborative setting. They will also develop skills pertaining to visualizing data and communicating research results.

For more information contact: Jonathan Sievers (sievers at physics dot mcgill dot ca).

Posted on 2025/02/07

ALBATROS is an array of independent radio antennas located at the McGill Arctic Research Station (MARS) that will, for the first time, image the sky below 10 MHz at high resolution. Each ALBATROS station operates autonomously and saves the radio signals through the arctic winter. The data is then brought back and processed offline. To obtain images of the sky, data from individual antennas must first be compensated for clock-drifts, and combined with nanosecond-level precision. The output of this step is transformed into a preliminary map of the sky, which needs to be corrected for ionospheric refraction. These steps constitute respectively the correlation, calibration, and imaging components of the ALBATROS analysis pipeline.

In this project, the student will test, enhance, and finally integrate each component of the analysis tools into one seamless software pipeline that can process several days of data. The student will be responsible for creating the code to test various components of the pipeline and analyze the quality of results. Ideally they would benchmark the throughput performance by imaging archival data from MARS. As each component of this pipeline is an active area of research, this project will introduce the student to computational and mathematical techniques at the forefront of low-frequency radio interferometry. The student will also gain exposure to high-performance computing on large CPU and GPU clusters, and working in a collaborative environment.

For more information contact: Jonathan Sievers (sievers at physics dot mcgill dot ca).

Posted on 2025/02/07

We are in the midst of a new generation of revolutionary materials that belong to the class of stacked two-dimensional crystals. These new materials have shown fascinating new properties, including superconductivity in twisted graphene bilayers and the observation of the fractional anomalous Hall effect, to name a couple. Most of these properties are electronic, however, vibrational properties are also expected to show fascinating new phenomena. The goal in this project is to synthesize large-scale twisted bilayers and to investigate their vibrational and thermal properties. This is a very hands-on project, which requires some patience, consistency, and the ability to learn and operate new technologies. The student will be involved in all aspects of the project and will work in the lab to synthesize, fabricate, characterize these new materials and the student will also be participate in the data analysis and contribute to the paper writing.

For more information contact: Michael Hilke (hilke at physics dot mcgill dot ca).

Posted on 2025/02/10

Thousands of extrasolar planets, or exoplanets, have been discovered, but most of them are completely different from the solar system worlds. Short period exoplanets exhibit phase variations as they orbit their star due to temperature contrasts of hundreds to thousands of K from day to night.  Infrared space telescopes can measure the thermal phase variations of an exoplanet, revealing the atmospheric temperature of the planet at different longitudes.  The Spitzer Space Telescope performed an extensive survey of thermal phase curve surveys for hot Jupiters, and more ambitious survey is planned for the European Space Agency’s Ariel mission. In the meantime, the James Webb Space Telescope (JWST) is measuring the phase-resolved emission spectra for a handful of hot exoplanets. This project entails adapting existing Python tools to analyze a recently-published uniform Spitzer survey of hot Jupiters and on recently obtained JWST observations of a hot Neptune.

The summer researcher will join the McGill Exoplanet Characterization Alliance and will work with Professor Cowan and senior PhD student Jared Splinter.  The intern will adapt Python code to convert the space-based infrared observations into quantitative constraints on the energy budgets of the target planets, e.g., their Bond albedo and day-to-night heat transport efficiency. For the Spitzer data, which include dozens of planets, the student will quantify trends in the inferred atmospheric properties, as a function of incident stellar flux, orbital period, surface gravity, etc. For the JWST data, the student will reconstruct spatially-resolved energy budgets for different regions of the planet to quantify local heat transport.

The student will join weekly group meetings and 1-on-1 meetings with Professor Cowan. They will make weekly progress reports and post their next research objectives on the group Slack. The student will learn about scientific programming, atmospheric science, and exoplanet observations. They will develop their scientific writing and visualization skills to present results succinctly and elegantly. They will learn how to solve problems independently, how to ask more experienced researchers for help, and how to adapt strategies when facing seemingly intractable problems. Prior programming experience in Python is a requirement. Astronomy coursework and research experience are a plus.

For more information contact: Nicolas Cowan (cowan at physics dot mcgill dot ca).

Posted on 2025/02/11

Thousands of extrasolar planets, or exoplanets, have been discovered, but most of them are completely different from the solar system worlds. Lava planets are rocky exoplanets that orbit so close their host star as to have a molten dayside.  The resulting atmosphere of vaporized rock flows supersonically to the planet’s nightside.  The extreme incident flux and fast winds lend themselves to atmospheric escape.  The student will quantify this process, in paying close attention to oxygen, which is one of the principal constituents of the bulk silicate Earth.

The summer researcher will join the McGill Exoplanet Characterization Alliance and will work with Professor Cowan and postdoc Dr. Giang Nguyen. The student will write or adapt Python code to estimate the mass of the dayside magma ocean on a handful of known lava planets.  The student will then estimate the atmospheric loss rate for these planets in the energy-limited regime, and will compare these estimates to hydrodynamical simulations in the literature. They will then quantify the impact of this loss on the chemistry of the magma ocean, and the entire planetary mantle. These inferences will have implications for near-term observations of lava planets with the James Webb Space Telescope.

The student will join weekly group meetings and 1-on-1 meetings with Professor Cowan. They will make weekly progress reports and post their next research objectives on the group Slack. The student will learn about scientific programming, atmospheric science, and exoplanet observations. They will develop their scientific writing and visualization skills to present results succinctly and elegantly. They will learn how to solve problems independently, how to ask more experienced researchers for help, and how to adapt strategies when facing seemingly intractable problems. Prior programming experience in Python is a requirement. Astronomy coursework and research experience are a plus.

For more information contact: Nicolas Cowan (cowan at physics dot mcgill dot ca).

Posted on 2025/02/11

Thousands of extrasolar planets, or exoplanets, have been discovered, but most of them are completely different from the solar system worlds. The European Space Agency’s Ariel mission is a space telescope launching in 2029 to complete a survey of exoplanet atmospheres.  The student will develop and use Python software tools to simulate Ariel observations of exoplanets. This will entail predicting the signal and noise for thousands of known exoplanets and planetary candidates, quantifying the diversity of potential targets, parameterizing possible exoplanet trends, and estimating observational time required to detect these trends.

The summer researcher will join the McGill Exoplanet Characterization Alliance and will work with Professor Cowan and postdoc Dr. Giang Nguyen. The student will write or adapt Python code to estimate the mass of the dayside magma ocean on a handful of known lava planets.  The student will then estimate the atmospheric loss rate for these planets in the energy-limited regime, and will compare these estimates to hydrodynamical simulations in the literature. They will then quantify the impact of this loss on the chemistry of the magma ocean, and the entire planetary mantle. These inferences will have implications for near-term observations of lava planets with the James Webb Space Telescope.

The student will join weekly group meetings and 1-on-1 meetings with Professor Cowan. They will make weekly progress reports and post their next research objectives on the group Slack. The student will learn about scientific programming, atmospheric science, and exoplanet observations. They will develop their scientific writing and visualization skills to present results succinctly and elegantly. They will learn how to solve problems independently, how to ask more experienced researchers for help, and how to adapt strategies when facing seemingly intractable problems. Prior programming experience in Python is a requirement. Astronomy coursework and research experience are a plus.

For more information contact: Nicolas Cowan (cowan at physics dot mcgill dot ca).

Posted on 2025/02/11

The nitrogen-vacancy (NV) center in diamond has become a leading platform for quantum sensing using the optically addressable spin states of the defect. Most notably, these spin states are sensitive to magnetic fields, offering the possibility for precision measurements based on the well-understood Zeeman interaction. However, interactions with other degrees of freedom in the diamond can also affect the spins, introducing inaccuracy into magnetic field estimation. Given the current state-of-the-art understanding of spin physics in diamond, our team is interested to explore the limits to absolute NV magnetometry -- how accurately can we reconstruct the magnetic field from physical constants, without relying on calibration with a reference magnetometer? This USRA project will fit into such a research direction by exploring a new consideration that has recently been identified: local electric fields associated with nearby ionized donors. To date, no one has studied how this interaction will impact the accuracy of NV magnetometry. By developing a model that predicts the magnetometer signals expected in the presence of local electric fields and fitting it to data, the USRA student will provide insight into the inaccuracy associated with this mechanism - and perhaps an approach to combat it.

The student will begin by understanding the existing models for the random distribution of local electric fields from ionized dopants, and how they impact the spin transition frequencies of the NV center. They will build a model for the asymmetric line-shape of the magnetometer signal that emerges and fit it to data from a commercial NV magnetometer. Given the sophistication of the model, care will need to be taken to enable fast execution; these efforts will be supported by collaborator Yves Bérubé-Lauzière at the Université de Sherbrooke, who has expertise in numerics. The USRA student will also explore the accuracy of analytic models using Monte-Carlo simulations of the random electric field distribution, and explore the inaccuracy associated with fitting to an analytic model. As time allows, the USRA student may participate in building more sophisticated models (including their electric field model) that will be used to fit data acquired in calibrated magnetic fields to benchmark the absolute accuracy of the magnetic field inversion.

An early schedule for the project (ending July 25th or before) is preferred.

For more information contact: Lily Childress (childress at physics dot mcgill dot ca).

Posted on 2025/02/11

Fast Radio Bursts are a new and mysterious astrophysical phenomenon in which short (few ms) radio bursts appear randomly in the sky. FRBs are thought to be extragalactic due to their dispersion measures that are far higher than the maximum amount available in our Milky Way. With FRB event rates of ~1000 /sky/day, they raise an interesting puzzle regarding their origin, which lie at cosmological distances. Radio pulsars are rapidly rotating, highly magnetized neutron stars. As compact objects, they embody physical extremes of gravity, density and magnetic field. Thanks to their amazing clock-like properties, radio pulsars can be used as cosmic laboratories for a variety of experiments ranging from tests of relativistic gravity to studies of the interstellar medium.

The Canadian Hydrogen Intensity Mapping Experiment (CHIME) is a new radio telescope recently built in Penticton, BC. CHIME's great sensitivity and large field-of-view (250 sq deg) enable the detection of many FRBs per day — in contrast to the fewer than 2 dozen discovered since 2007. CHIME is also an excellent pulsar observatory, able to detect hundreds of pulsars every day and enabling novel experiments using these high cadence observations.

Here are proposed several possible research projects involving data from CHIME. Possibilities include improving FRB characterization, studying repeating FRBs, localizing FRBs, monitoring radio pulsars, and developing software tools to search for pulsars with CHIME.

The student, who should have experience and familiarity with programming in the Linux environment, will be given astrophysical data sets from CHIME to first familiarize themselves with source properties. Then, depending on exact interest, will analyze existing data obtained in order to understand FRBs or the radio pulsar population, or help develop and test new algorithms for our new pulsar searching pipeline.

For more information contact: Victoria Kaspi (vkaspi at physics dot mcgill dot ca).

Posted on 2025/02/11

Supervisors: Dr. Lauren Rhodes, Prof. Daryl Haggard

Gamma-ray bursts (GRB) are ~seconds-long flashes of gamma-ray radiation emitted when the most massive stars die. It is thought that when the stars reach the end of their lifetimes, a black hole or neutron star forms in the centre and material accreting onto central object launches a highly relativistic jet which produces the GRB. When the jet interacts with the circumburst environment a synchrotron afterglow is produced. Studies of this afterglow inform us of the energy present in the jet, the properties of the progenitor star’s wind and particle acceleration. The AMI-LA radio interferometer in the UK has been searching for and studying the radio emission from GRB afterglows.

In this project the student will use data collected with AMI-LA and combine it with public X-ray and (where available) optical data to study at least one of the afterglows that we have detected. They will compare the light curve and spectral information to theoretical models to better understand the jet physics and extract physical parameters of the systems. This work will contribute a journal article being written on the population of GRBs afterglows detected with AMI-LA. Depending on the progress of the student there is possibility for examining these events at a population level. For this project, it is expected that the student has taken a course on astrophysics – or related – and has experience of coding in python.

The student will receive excellent training from several PhD-level scientists and in the Haggard research group and the Trottier Space Institute. This will take the form of weekly meetings and more frequent informal interactions with the group in the form of hack sessions, seminars, and networking events.

For more information contact: Daryl Haggard (dhaggard at physics dot mcgill dot ca).

Posted on 2025/02/11

Supervisors: Dr. Sophia Waddell, Prof. Daryl Haggard

Active Galactic Nuclei, or AGN, are powered by supermassive black holes which are actively accreting material. With masses of millions to billions of times that of the Sun and emitting over a broad range of wavelengths from radio to X-rays and Gamma rays, they are responsible for some of the most extreme and energetic phenomena in the Universe. By studying these objects using X-ray data, we can probe the heart of the supermassive black hole, in the final moments before material is sucked in and where extreme general relativistic effects occur.

For this project, the student will use pre-processed, public X-ray data from one or more X-ray telescopes (NuSTAR, Swift, Suzaku) in order to study the X-ray corona; a cloud of hot electrons located close to the supermassive black hole which is so hot, it shines in X-rays. Data from the nearby black hole MCG+04-22-042 will be used,  a source which shows interesting variability patterns when studying the long term behaviour, where small flares in very high energy X-rays have been found. The student(s) will model the data to search for variations in the properties of the X-ray corona, specifically the optical depth and temperature. This work will then be published in an astronomical journal. The work could later be expanded to include other sources which show similar behaviour. For this project, it is expected that the student has taken a course on astrophysics or similar, and has experience of coding and basic plotting in python.

The student will receive excellent training from several PhD-level scientists and in the Haggard research group and the Trottier Space Institute. This will take the form of weekly meetings and more frequent informal interactions with the group in the form of hack sessions, seminars, and networking events.

For more information contact: Daryl Haggard (dhaggard at physics dot mcgill dot ca).

Posted on 2025/02/11

Supervisors: Nicole Ford (PhD Candidate), Prof. Daryl Haggard

The Event Horizon Telescope observes a sample of non-horizon "low luminosity" active galactic nuclei known as the ETHER sample. The project with utilize light curves, basic time domain photometric observations, from the TESS and/or eROSITA telescopes to study the variability of these active nuclei. The project will involve both literature and archival searches to offer the longest time baseline study of these targets and to model their accretion flows and jet emission properties.

For this project, the student will use pre-processed, public time domain data from the Transiting Exoplanets Survey Satellite (TESS) and/or the eROSITA X-ray instrument to study accretion onto growing supermassive black holes. These archival data will complement observations from the Event Horizon Telescope of the same sources, allowing the student to model their broadband spectral energy distributions. The student will model the data spectrally and temporally to study mass inflow and outflow. This work will then be published in an astronomical journal. For this project, it is expected that the student has taken a course on astrophysics or similar, and has experience of coding and basic plotting in python.

The student will receive excellent training from an upper level PhD student and a Professor of Physics, as well as in the Haggard research group and the Trottier Space Institute. This will take the form of weekly meetings and more frequent informal interactions with the group in the form of hack sessions, seminars, and networking events.

For more information contact: Daryl Haggard (dhaggard at physics dot mcgill dot ca).

Posted on 2025/02/11

New windows on the cosmos that can revolutionize our understanding of fundamental physics are ushered in with new technology. We are developing the CHORD telescope that is now under construction near Penticton, BC. It will be the largest and most powerful telescope ever built on Canadian soil.

This project will involve the testing and characterization of new instrumentation for the CHORD telescope.

The student will engage in both software development for instrumentation and lab measurements. Detailed documentation and reporting will be required.

The student will join the Cosmology Instrumentation Laboratory and participate in the full cycle of scientific research, attending group meetings, team work sessions, and 1-on-1 meetings with other group members. They will be able to participate in the Trottier Space Institute Summer Program, where there will be weekly workshops on professional development and research skills.

For more information contact: Matt Dobbs (matt dot dobbs at mcgill dot ca).

Posted on 2025/02/11

Squeezed states constitute an important class of quantum states of light, underpinning a wide range of applications from gravitational detection to quantum sensing. Generating squeezed states in optical frequencies based on an optical cavity with more than one mode and nonlinear crystals faces many challenges in finding optimal parameters. Using neural networks to help the experiments of optical parametric oscillators (OPOs) holds great promise in improving OPO's performance, e.g., in the degree of squeezing and generation of novel states.

The student's role is to develop a numerical code that implements a customized neural network for finding optimal parameters in an OPO setup and achieve the training of the neural network using theoretically generated data. With the help of a postdoc, the student will have access to the lab to acquire experimental data and adapt the neural network to realistic lab settings. If time permits, the student may explore more intricate quantum state generation, such as non-Gaussian states.

For more information contact: Kai Wang (wkai at physics dot mcgill dot ca).

Posted on 2025/02/11

In quantum nonlinear integrated photonics, such as on-chip squeezed light generation [1], which promises many applications such as quantum computing [2], it is crucial to phase lock multiple continuous-wave pump lasers. While there are many existing approaches to actively lock lasers at a single frequency, it is much more difficult to lock lasers at different frequencies, especially if the frequency difference is large. This project aims to experimentally achieve the locking of at least two lasers with a couple of hundred gigahertz difference in frequency. It will be based primarily on beating a laser to the higher-order side bands of an electro-optically modulated laser, with the possibility of using four-wave-mixing in a highly nonlinear fiber [3] to further extend the bandwidth of the frequency comb for the locking.

The student will build the setup for this laser locking system with the help of a PhD student or postdoc. Such a locking system includes optical aspects (primarily laser and fiber optics), electronics (FPGA and some analog electronics), as well as programming.

[1] Zhang, Y., Menotti, M., Tan, K. et al. Squeezed light from a nanophotonic molecule. Nat Commun 12, 2233 (2021).
[2] Aghaee Rad, H., Ainsworth, T., Alexander, R.N. et al. Scaling and networking a modular photonic quantum computer. Nature (2025)
[3] Flavio C. Cruz, “Optical frequency combs generated by four-wave mixing in optical fibers for astrophysical spectrometer calibration and metrology,” Opt. Express 16, 13267-13275 (2008)

For more information contact: Kai Wang (wkai at physics dot mcgill dot ca).

Posted on 2025/02/11

Photons encoded in the discrete-time degree of freedom constitute a promising platform for quantum computing with the advantage of compactness and operation at room temperature [1]. However, the design of such optical-fiber-loop-based devices for quantum machine learning tasks remains lacking. Judiciously designed optical setups can potentially realize a variety of quantum machine learning algorithms, such as quantum reservoir computing in the time domain [2] and quantum self-learning machines [3].

The student working on this project will theoretically design an optical fiber-loop-based setup for quantum machine learning that is suitable for running at least one type of algorithm. After the design is achieved, the student might have a hands-on opportunity to build a simple part of the proposed fiber setup.

[1] B. Bartlett, A. Dutt, and S. Fan, Deterministic Photonic Quantum Computation in a Synthetic Time Dimension, Optica 8, 1515 (2021).
[2] J. Chen, H. I. Nurdin, and N. Yamamoto, Temporal Information Processing on Noisy Quantum Computers, Phys. Rev. Appl. 14, 1 (2020).
[3] V. Lopez-Pastor and F. Marquardt, Self-Learning Machines Based on Hamiltonian Echo Backpropagation arXiv:2103.04992 (2021).

For more information contact: Kai Wang (wkai at physics dot mcgill dot ca).

Posted on 2025/02/11

Meta-optics, primarily metasurfaces made from a layer of nanostructures, is an emerging new type of optical element that has great flexibility in manipulating light in all degrees of freedom, from spatial to polarization to frequencies. An essential task after a meta-optics element is fabricated is the characterization of its linear transformations in these degrees of freedom. In particular, it is highly desirable to characterize a metasurface's spatial impulsive response, which is known as the point spread function (PSF). This is even more intriguing if the characterization is combined with a spectral measurement, i.e., measuring a spatial-spectral PSF.

The student will adapt an existing setup designed for characterizing metasurfaces to include the capabilities of measuring their spatial and spectral impulsive responses through a white-light point-like source illumination (or structured light illumination) and hyperspectral imaging through a spectrograph. The student, with the help of a more experienced student or postdoc, will need to design and implement the modified setup and program its automation and data processing.

For more information contact: Kai Wang (wkai at physics dot mcgill dot ca).

Posted on 2025/02/11

Quantum estimation theory has been shown to be a powerful theoretical framework for superresolution imaging, e.g., in resolving the separation between two incoherent point sources beyond Rayleigh's criterion [1]. Meta-optics, primarily metasurfaces made from a layer of nanostructures, is an emerging new type of optical element that has great flexibility in manipulating light in all degrees of freedom. This project aims to inversely design a metasurface that optimizes the classical Fisher information of estimating a simple imaging parameter that can saturate or approach the fundamental limit predicted by the quantum Fisher information.

The student will learn the theoretical framework of quantum estimation theory and metasurface simulation method and write a code to optimize the metasurface based on classical Fisher information of a certain estimation problem.

[1] M. Tsang, et al. Quantum theory of superresolution for two incoherent optical point sources. Phys. Rev. X 6, 031033(2016).

For more information contact: Kai Wang (wkai at physics dot mcgill dot ca).

Posted on 2025/02/11

Colliding heavy nuclei at relativistic energies (Relativistic Heavy Ion Collisions) is the only way we can re-create the conditions of the very early Universe when the temperature was so high quarks and gluons could not yet form ordinary nuclear matter. To study this primordial form of matter (Quark-Gluon Plasma), full-scale simulations of relativistic heavy ion collisions are essential. An integral part of the simulation is the modeling of the colliding nuclei in terms of the gluon field, and how the gluon fields from the projectile and the target nuclei interact and evolve after the collision. The nuclear theory group has its own model called IP-Glasma based on many-body QCD in both the 2D mode and the 3D mode.

For this project, the student will work on generating theoretical data for a few different models and parameter sets of the 3D initial conditions. Specifically, the student will run the 3D IP-Glasma code with various modifications of the rapidity structure of the model to find a way to systematically improve the model to describe the experimental rapidity distributions observed at the LHC. By carrying out this project, the student will learn the basics of quantum chromodynamics, relativistic heavy ion phenomenology, and numerical methods. The student will be supervised by S. Jeon and mentored by the postdoctoral fellow, Dr. Xiang-Yu Wu

For more information contact: Sangyong Jeon (sangyong dot jeon at mcgill dot ca).

Posted on 2025/02/13

The sky is buzzing with flashes of radio waves coming from both mysterious sources within our Milky Way Galaxy and from deep extragalactic space. These fast radio transients are associated with extreme astrophysical environments where high energy density and huge magnetic field can accelerate charged particles and lead to laser-like coherent emission. The nature of fast radio transients remains a highly topical astrophysical puzzle: what types of extreme objects, like neutron stars and black holes, might be responsible and how do they create these radio flashes? At the same time, impulsive radio signals are a great way to probe the otherwise invisible ionised medium and magnetic field between stars and galaxies. Fast radio transients are thus of great scientific benefit, but identifying them with radio telescopes is a major challenge - because of their ephemeral nature, rare occurrence, and the large number of false positives created by artificial interfering signals. In this summer project, the student will help develop a methodology that includes the use of polarimetry to identify astrophysical signals in radio telescope data. Compared to an approach that uses only the total intensity of the signal, using the full set of Stokes parameters can potentially identify astrophysical transients that are currently being missed in ongoing searches. We will use data from the CHIME/FRB system, a premier Canadian telescope and the global leader in fast transient discovery.

The student will be a full member of the Canada Excellence Research Chair (CERC) in Transient Astrophysics research group led by Prof. Jason Hessels and will therefore experience the full cycle of scientific research. They will attend weekly group meetings and hack sessions with other group members. They will meet with supervisor Hessels, and other co-supervisors, once a week to discuss progress and open problems. They will also be able to participate in the Trottier Space Institute Summer Program, where there will be weekly workshops on professional development and research skills.

For more information contact: Jason Hessels (hessels at physics dot mcgill dot ca).

Posted on 2025/02/18

he EXO (Enriched Xenon Observatory) collaboration is searching for lepton-number violating neutrino-less double beta decays (0νββ) in Xe-136. A positive observation would require the neutrino to be its own anti-particle, i.e. the neutrino has to be a Majorana particle, and shed light on various open questions in neutrino physics. The EXO collaboration is pursuing the development of the next-generation experiment called nEXO. This advanced detector requires the development of new technologies as well as detailed knowledge of the underlying physical processes to reach a sensitivity goal to the 0νββ half-life of 10^{28<\sup> years.}

We have been developing the Light-only Liquid Xenon (LoLX) experiment at our lab at McGill which aims to measure the emission of Cherenkov light in liquid xenon (LXe), investigate crosstalk between silicon photomultiplier devices, and deepen our understanding of light emission in LXe. These measurements will help constrain our simulation models for nEXO. LoLX may also improve event identification and suppress backgrounds by separating events where one or two electrons are emitted. This summer, we plan to perform several measurements with SiPMs installed in our upgraded LoLX cryostat. In addition, we plan to characterize the performance of these devices under intense UV light irradiation.

Your main task will be to simulate the expected response function of SiPMs in LoLX using the ray-tracing package CHROMA (GPU-based). You will also support the operation of the cryostat, participate in data taking campaigns and compare simulation results to recorded data. You will be embedded within the local neutrino group at McGill and learn about particle physics, the use of liquid xenon as a radiation detector, and how to read cryogenic temperatures using thermocouples and RTDs.

This project is aimed at undergraduate students at all levels. All you need is an interest in nuclear/particle physics and a strong willingness to learn. Programming knowledge in any language (C or Python preferred) would be beneficial but is not necessary, as we have local experts who will be happy to teach you. You will apply your knowledge of thermodynamics in a real life experiment, and take part in the operation of the upgraded LoLX cryostat.

For more information contact: Thomas Brunner (thomas dot brunner at mcgill dot ca).

Posted on 2025/02/20

The EXO (Enriched Xenon Observatory) collaboration is searching for lepton-number violating neutrino-less double beta decays (0νββ) in Xe-136. A positive observation would require the neutrino to be its own anti-particle, i.e. the neutrino has to be a Majorana particle, and shed light on various open questions in neutrino physics. The collaboration is pursuing the development of the next-generation experiment called nEXO. This advanced detector requires the development of new technologies as well as detailed knowledge of the underlying physical processes to reach a sensitivity goal to the 0νββ half-life of 10^{28<\sup> years. nEXO intends to use 5 tonnes of liquid Xe enriched to 90% in the double-beta decaying isotope Xe-136.}

One of the challenges to realize nEXO is the procurement of Xe-136. While conventional methods of extracting natural Xe from air and subsequently enriching the gas in the isotope Xe-136 are feasible, they are exposed to large price fluctuations in the Xe market. A significant amount of Xe-136 is actually present as fission product in spent nuclear fuels. If one could extract this Xe, it could reduce the cost and risk of the nEXO experiment. The goal of this summer project is to search literature on extracting noble gasses from spent nuclear fuel and to estimate the amount of Xe gas that is currently present in spent nuclear fuel in Canada. Based on these studies, you will estimate if sufficient Xe-136 can be extracted from nuclear fuel to fill the nEXO detector.

This project consists of literature search and calculations. You will be supported by Thomas Brunner and researchers at CNL. You are expected to visit the facilities at Chalk River in Ontario at least once over the summer. At the end of the summer you will submit a report that will outline whether is it feasible to consider spent nuclear fuel as a source for Xe for rare-event searches with nEXO.

For more information contact: Thomas Brunner (thomas dot brunner at mcgill dot ca).

Posted on 2025/02/20

This research aims to further understand current techniques in the fabrication and characterization of atomically thin 2D materials and their use in the stacking process for heterostructures, composed of two (or more) 2D flakes of materials held together by Van der Waals (vdW) forces. These structures are of interest due to their many interesting properties and variety in composition.

Mechanical exfoliation, a simple process utilizing adhesive tape to peel layers off bulk crystals, is performed to obtain atomically thin samples of materials such as hexagonal boron nitride (hBN) and Molybdenum disulfide (MS2). This process is possible due to the weak interlayer vdW forces in hBN and MS2. Using adhesive tape potentially leaves residues on the surface of the 2D sample. The aim of this project is to understand how to create residue free surfaces.

To achieve this, the student will learn how to

1. Mechanically exfoliate a thin layer of a 2D sample.
2. Characterize the chemistry of the surface using Raman spectroscopy. The Raman spectrum ‘fingerprints’ molecules.
3. Perform AFM measurements to evaluate surface roughness and contamination using tapping mode AFM. Tapping mode and phase imaging allow the identification of heterogeneous materials on surfaces – a 2D material without adhesive contaminants will be atomically smooth and not show variations in the phase channel. The phase channel in tapping mode AFM is sensitive to local adhesion properties.
4. Expose sample to ozon/UV cleaning, O2 plasma, heat in vacuum or ultra high vacuum and use ‘nanobrooming’ by contact mode AFM to evaluate effectiveness of cleaning procedures. The effectiveness will be evaluate by tapping mode AFM imaging as well as Raman spectroscopy on the same sample before/after the cleaning procedure.

The student will be supervised on a daily basis by a PhD student in the Grütter group and have weekly progress meetings with the supervising faculty. It is expected that this systematic study will lead to a scientific publication.

For more information contact: Peter Grütter (peter dot grutter at mcgill dot ca).

Posted on 2025/02/20

We aim to model the electrostatics of atomically precise manufactured structures in Silicon. In particular, we want to know the electrostatics of a single, atomically precise manufactured quantum dot. This quantum dot is connected to an in-plane gate electrode (‘the ‘source’) and scanned by an atomic force microscopy (AFM) tip with an applied voltage bias.

This will allow us to determine the voltage dropped across this quantum dot as a function of device geometry. Furthermore, it will enable the investigation of single electron charging of the quantum dot using the AFM tip as an electrostatic gate and simultaneously a charge sensor with single electron sensitivity.

In this project, the student will learn how to

1. Model the electrostatics of this system using commercial software
2. Determine the sensitivity of the potential drop across the quantum dot as a function of the atomic scale device geometry
3. Calculate the quantomechanical energy eigenstates of an individual As or P atom
4. Calculate the bias needed to ionize this single atom dopant by the source and tip as a function of their atomic scale position.

The student will be supervised on a daily basis by a PhD student in the Grütter group and have weekly progress meetings with the co-supervising faculty. It is expected that this systematic study will lead to a scientific publication.

For more information contact: Peter Grütter (peter dot grutter at mcgill dot ca).

Posted on 2025/02/20

Single-photon emitters (SPEs) have emerged as essential components for advancing quantum technologies, including quantum communication, computing, and secure cryptography. Hexagonal boron nitride (hBN), a two-dimensional material capable of single-photon emission (SPE) at room temperature, offers unique advantages due to its optical properties and potential for reliably engineering SPE defects into the material.

These defects can be generated by annealing hBN in vacuum or mechanically by atomic force microscopy (AFM)

In this project, the student will learn how to

1. exfoliation of hBN samples
2. operate an AFM for morphological mapping and generation of defects
3. anneal these samples in a vacuum furnace
4. measure the photoluminescent responses of the generated defects

The student will be supervised on a daily basis by a PhD student in the Grütter group and have weekly progress meetings with the supervising faculty. It is expected that this systematic study will lead to a scientific publication.

For more information contact: Peter Grütter (peter dot grutter at mcgill dot ca).

Posted on 2025/02/20

https://www.physics.mcgill.ca/siwicklab/

Combining ultrafast lasers and electron microscopes in novel ways makes it possible to directly `watch' the time-evolving structure of condensed matter and interrogate couplings between carrier and lattice degrees of freedom on the fastest timescales open to atomic motion [1-5]. By combining such measurements with complementary (and more conventional) spectroscopic techniques we can now develop structure-property relationships for materials under even very far from equilibrium conditions, explore how we can use light to control the properties of materials [2,3] and unravel the complex interplay between charge, spin, orbital and lattice-structural degrees of freedom that gives rise to the emergent macroscopic properties of materials.

SnSe is a remarkable thermoelectric material [5], and has been predicted to host a number of non-equilibrium, light-induced phases [6]. The Siwick group plans to investigate these photoinduced phases with ultrafast electron scattering techniques. This requires the development of high-temperature sample holder that can be easily attached to the existing instrument and operated with the other equipment in the lab.

This project will involve the design, simulation (using COMSOL), manufacturing and implementation of a high-temperature sample stage for these and other experiments. The goal will be to take temperature dependent electron scattering data through the Pnma -> Cmcm phase transition in SnSe with this stage by the end of the summer.

This project is suitable for a U2 or U3 student in any of the undergraduate physics programs

[1] D. Filippetto et al., Reviews of Modern Physics 94 (2022) 045004.
[2] Morrison et al. Science 346 (2014) 445
[2] Otto et al., PNAS, 116 (2019) 450
[3] Stern et al., Phys. Rev. B 97 (2018) 165416
[4] Rene de Cotret et al., Phys. Rev. B 100 (2019) 214115
[5] Rene de Cotret et al., PNAS, 119 (2022) e2113967119
[6] S. Mocatti et al., J. Phys. Chem. Lett. (2023), 14, 41, 9329­9334

For more information contact: Brad Siwick (siwick at physics dot mcgill dot ca).

Posted on 2025/02/20

https://www.physics.mcgill.ca/siwicklab/

Combining ultrafast lasers and electron microscopes in novel ways makes it possible to directly `watch' the time-evolving structure of condensed matter and interrogate couplings between carrier and lattice degrees of freedom on the fastest timescales open to atomic motion [1-5]. By combining such measurements with complementary (and more conventional) spectroscopic techniques we can now develop structure-property relationships for materials under even very far from equilibrium conditions, explore how we can use light to control the properties of materials [2,3] and unravel the complex interplay between charge, spin, orbital and lattice-structural degrees of freedom that gives rise to the emergent macroscopic properties of materials.

RF cavities have many important applications in electron beam applications. The ultrafast electron scattering instruments in the Siwick lab uses RF cavities to perform electron pulse compression [6] and electron beam deflection operations. To optimize electron pulse compression and to explore new applications for RF cavities we need to design two new cavities; a ~9GHz TM₀₁₀ mode compression cavity and another ~3GHz TM₁₁₀ cavity. We have 2 computational electromagnetics packages with which to perform this design work (SuperFish and HFSS). The performance of these cavities in our instrument can also be simulated using the General Particle Tracer (GPT) code.

This project will involve the design, simulation and manufacturing and of the cavities.

This project is most suitable for a U3 student that has taken PHYS 340/PHYS 342 and PHYS 350/PHYS 352 in any of the undergraduate physics programs.

[1] D. Filippetto et al., Reviews of Modern Physics 94(2022) 045004.
[2] Morrison et al. Science 346(2014) 445
[2] Otto et al., PNAS, 116(2019) 450
[3] Stern et al., Phys. Rev. B 97(2018) 165416
[4] Rene de Cotret et al., Phys. Rev. B 100(2019) 214115
[5] Rene de Cotret et al., PNAS, 119(2022) e2113967119
[6] M. R. Otto et al., Structural Dynamics 4(2017) 051101; R. P Chatelain Appl. Phys. Lett. 101(2012) 081901; T. van Oudhesden et al. J. Appl. Phys. 102(2007), Art. No. 093501

For more information contact: Brad Siwick (siwick at physics dot mcgill dot ca).

Posted on 2025/02/20