Events List for the Academic Year
Event Time:
Thursday, October 17, 2024 | 10:00 am - 11:00 am
Event Location:
AMPEL 311
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2024-10-17T10:00:00
2024-10-17T11:00:00
Quantum Sensation: a journey through arts and quantum physics
Event Information:
After a presentation of her artistic path and research, the painter Caroline Delétoille will share some insights about the "quantum sensation" art-science project embedded at the core of her upcoming residency. This research-creation based exhibition has been developed since the end of 2023 in close collaboration with a physicist and a philosopher. Its artistic creation and exploration will continue during the residency at the QMI laboratories.
Event Location:
AMPEL 311
Event Time:
Thursday, October 10, 2024 | 4:00 pm - 5:00 pm
Event Location:
HENN 201
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2024-10-10T16:00:00
2024-10-10T17:00:00
Teaching & Learning Quantum Computing
Event Information:
Abstract:
As quantum information science and engineering continues to gain momentum, more courses dedicated to teaching these ideas are being offered at every instructional level. As new courses, programs, and certificates are being developed, there is a unique opportunity for research-based instruction to be embedded into the curriculum. Our work focuses on the introduction of quantum computing content in advanced undergraduate and early graduate courses. At this level, students have taken a significant number of technical courses. At the same time, students enroll in these courses from a variety of majors, including math, engineering, computer science, and physics. We focus on understanding student thinking as they learn foundational quantum information topics from these diverse backgrounds. I will present results on where quantum computing courses are being offered, what content is taught, the development of a conceptual survey on quantum computing, and research into student understanding.
Bio:
I am a physics professor at California State University, Fullerton. My research field is Physics Education Research, with a focus on the teaching and learning of quantum mechanics and quantum information science. My Ph.D. is from the University of Waterloo, where I studied quantum computing. I transitioned to the field of Physics Education Research with a postdoctoral position at the University of Washington. My research group studies how students learn quantum mechanical ideas and develop research-based instructional materials to improve student learning.
Learn More:
See her faculty page from California State University Department of Physics faculty profiles: https://physics.fullerton.edu/people/faculty-and-staff/?itemID=40b6-ae61-d31e536
View some of her presentations on student understanding of quantum mechanics and quantum information science here: https://underline.io/speakers/8808-gina-passante
Read her interview/Physicist profile from the American Physical Society (APS) Careers page: https://www.aps.org/careers/profiles/gina-passante
Event Location:
HENN 201
Event Time:
Thursday, October 10, 2024 | 10:00 am - 11:00 am
Event Location:
AMPEL 311
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2024-10-10T10:00:00
2024-10-10T11:00:00
Atomic Cluster Expansion for "Learning" Many-Body Interaction
Event Information:
The integration of machine learning (ML) into the traditional modeling workflows is replacing decades-old - often ad hoc - approximations (e.g., in constitutive laws) leading to new models that far outstrip their predecessors in accuracy and transferability. ”Pure” ML approaches are rarely successful but remarkable results can be achieved when integrated with domain knowledge. I will introduce a general formalism, the Atomic Cluster Expansion, for parameterizing many-body interaction and how it can be used for reduced-order modelling. Examples are taken from interatomic potentials, coarse-grained MD, and VMC.
Event Location:
AMPEL 311
Event Time:
Wednesday, October 9, 2024 | 5:30 pm - 7:30 pm
Event Location:
HEBB 100
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2024-10-09T17:30:00
2024-10-09T19:30:00
Fall 2024 Undergrad Science Slam!
Event Information:
Join us for this thrilling and educational science communication contest, showcasing six undergraduate student presenters explaining complex physics and astronomy topics without the use of academic or technical language/slides.
Clear science communication is the bridge that brings science to the world. Be inspired by our students as they share their knowledge of physics and astronomy with you!
High school student, parents and families welcome. PHAS undergrads, come cheer on your peers!
Faculty and staff advisors will be in attendance for questions after the event.
Registration is on Eventbrite here, or via the QR code below:
See you there!
Event Location:
HEBB 100
Event Time:
Monday, October 7, 2024 | 4:00 pm - 5:00 pm
Event Location:
HENN 318
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2024-10-07T16:00:00
2024-10-07T17:00:00
The Dusty Side of Star Formation
Event Information:
Abstract:
The majority of light from cosmic star formation is absorbed by dust and reradiated into the far-infrared (FIR). Since their discovery in the late 1990s, the most luminous high-redshift FIR galaxies have been heavily studied using single-dish submillimeter telescopes, but the bulk of the FIR light is in galaxies that are too faint to be seen this way. I will discuss why mapping the FIR emission in fainter galaxies has been a difficult problem and then talk about how, with the combination of JWST, ALMA, and single-dish submillimeter telescopes, we may be coming closer to a solution. Finally, I will discuss other issues, such as finding the redshifts of the galaxies, that still need to be addressed.
Bio:
Amy J. Barger is an American astronomer and Henrietta Leavitt Professor of Astronomy at the University of Wisconsin–Madison. She is considered a pioneer in combining data from multiple telescopes to monitor multiple wavelengths and in discovering distant galaxies and supermassive black holes, which are outside of the visible spectrum. Barger is an active member of the International Astronomical Union (Bio from Wikipedia here).
Learn More:
View her Faculty webpage from the University of Wisconsin-Madison: https://www.astro.wisc.edu/staff/barger-amy/
See her personal webpage here: http://user.astro.wisc.edu/~barger/
Check the NASA pages for information on Star Basics: https://science.nasa.gov/universe/stars/ and the Formation of Stars: https://www.nasa.gov/image-article/formation-of-stars/
Links & Resources:
Chapters and articles from Science Direct on the subject of 'High Redshift galaxies': https://www.sciencedirect.com/topics/physics-and-astronomy/high-redshift-galaxy
Article from Astrobites: "JWST smashes the record for the earliest galaxy": https://astrobites.org/2022/12/16/jwst-jades/
Event Location:
HENN 318
Event Time:
Monday, October 7, 2024 | 2:30 pm - 3:30 pm
Event Location:
HENN 318
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2024-10-07T14:30:00
2024-10-07T15:30:00
PHAS Monday Tea
Event Information:
Welcome everyone to Monday Tea!
This is a weekly event for students, staff and faculty to meet new-to-you colleagues, catch up with your community and to learn about what's happening in the PHAS Department.
Meet your hosts in the EDI Community Building Working Group:
Jess McIver
Adele Ruosi
Megan Bingham
Evan Goetz
Mona Berciu
Howard Li
Mandana Amiri
See you there!
Event Location:
HENN 318
Event Time:
Thursday, October 3, 2024 | 4:00 pm - 5:00 pm
Event Location:
HENN 201
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2024-10-03T16:00:00
2024-10-03T17:00:00
New twists on topology in moiré quantum matter
Event Information:
Abstract:
Over the past two decades, condensed matter physicists have steadily mastered the isolation and control of two-dimensional van der Waals materials. These systems host a broad range of intriguing new quantum phases, enabling studies of unconventional superconductivity and strongly correlated states. Much of this progress has been driven by moiré superlattices, formed by stacking and twisting atomically thin crystalline sheets. These materials can feature flat electronic bands with strong Coulomb interactions, often giving rise to emergent collective states with exotic topological properties. I will first discuss scanning tunneling microscopy experiments that probe the microscopic origins of topological states in twisted 2D semiconductors. Then, I will present electrical transport measurements in various graphene-based moiré systems revealing topological crystals of electrons and their interplay with competing states featuring fractionally charged quasiparticles. These systems are poised to become a focus of intensive study in the coming years due to their wealth of correlation-driven topological physics and their potential applications in future quantum devices.
Bio:
Matthew Yankowitz is an Associate Professor of Physics and Materials Science & Engineering at the University of Washington. His research in experimental condensed matter physics focuses on the investigation and control of strong correlations, magnetism, superconductivity, and topology in two-dimensional van der Waals heterostructures, probed using a combination of electrical transport and scanning tunneling microscopy. Prior to joining the University of Washington, he was a postdoctoral researcher at Columbia University and received his Ph.D. in Physics from the University of Arizona. He is the recipient of an ARO Young Investigator Award (2020), an NSF CAREER Award (2021), the Lee Osheroff Richardson Science Prize from Oxford Instruments (2021), and the IUPAP Young Scientist Prize in Low Temperature Physics (2022).
Learn More:
See Matthew's lab here
View his University of Washington faculty page: Matthew Yankowitz | Department of Physics | University of Washington
Event Location:
HENN 201
Event Time:
Thursday, October 3, 2024 | 10:00 am - 11:00 am
Event Location:
AMPEL 311
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2024-10-03T10:00:00
2024-10-03T11:00:00
Introducing the Ramaniton: The quasiparticle for Raman scattering
Event Information:
In Raman scatering, pump photons that are incident on a material are able to emit or absorb materials' excitations such as phonons and orbital transitions. This process generates red-shifted (Stokes) and blue-shifted (antiStokes) photons that are usually uncorrelated with each other. When real or virtual excitations emitted by a Stokes photon are coherently absorbed by another pump photon, an entangled Stokes-antiStokes photon pair is created, in a process analogous to the formation of Cooper pairs in superconductors [1].In this talk we will show that this mechanism provides the microscopic underpinning for the phenomena of four-wave mixing in quantum optics, one of the main methods to generate squeezed states of light that are key to proposals of quantum computing, sensing, and communication with photons. We will argue that it's fruitful to take a "condensed matter physics approach" and treat Raman-interacting photons and phonons as a hybrid excitation, the Ramaniton quasiparticle [2]. The Ramaniton enables nonperturbative theories for the evolution of photons in waveguides formed by group IV semiconductors such as silicon and diamond, enabling the design of photonic devices that exploit optical phonons for optimal generation of two-mode squeezed states of light. [1] A. Saraiva, F.S.D.A. Júnior, R. De Melo E Souza, A.P. Pena, C.H. Monken, M.F. Santos, B. Koiller, and A. Jorio, Photonic Counterparts of Cooper Pairs, Phys. Rev. Lett. 119, 193603 (2017).[2] S. Timsina, T. Hammadia, S.G. Milani, F.S.D.A. Júnior, A. Brolo, and R. de Sousa, Resonant squeezed light from photonic Cooper pairs, Phys. Rev. Res. 6, 033067 (2024).
Event Location:
AMPEL 311
Event Time:
Thursday, September 26, 2024 | 4:00 pm - 5:00 pm
Event Location:
HENN 201
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2024-09-26T16:00:00
2024-09-26T17:00:00
Queering Physics: A History of the Queer Rights in the USA and LGBT+ Advocacy in Physics
Event Information:
Abstract:
Queer civil rights in the USA have been hard won from direct activism and organization of a diverse coalition of people, including trans women and men, People of Color, and members of the LGBT+ community more broadly. This talk will explore this history and take an in-depth look at how principles from this history were applied to physics to make significant policy changes. The data presented will uncover a concerning climate for LGBT+ physicists, which can be even more challenging for trans persons and People of Color. The talk will conclude with concrete actions that everyone can take to become more informed about Queer Studies and implement impactful best practices in their own lives.
Bio:
Ramón Barthelemy is an associate professor of physics and astronomy at the University of Utah and a fellow of the American Physical Society. Previous to his faculty position Ramón was a Fulbright Scholar in Finland, a Science Policy Fellow in the U.S. Department of Education and a private sector consultant. His work focuses on the lives, educational experiences, and career paths of marginalized students in physics and STEM. This has included work on LGBT+ people, graduate Students of Color, and women in physics. Through this work he has become a global leader on LGBT+ inclusion in STEM with dozens of publications and over $5M in National Science Foundation funding. Ramón was the 2020 recipient of the Fulbright Finland Alumni Award, the 2021 recipient of the AAPT Doc Brown Futures award, the 2022 WEPAN Research award recipient, the 2023 Out to Innovate LGBTQ+ Educator of the Year, and a 2023 awardee for the APS 5 Sigma award for science advocacy.
Learn More:
View Ramón Barthelemy's faculty page: RAMON BARTHELEMY - Home - Faculty Profile - The University of Utah
Read University of Utah Department of Physics & Astronomy article on Ramón here: Ramón Barthelemy – Department of Physics & Astronomy (utah.edu)
Read University of Utah College of Science article on Ramón here: Humans of the U: Ramón Barthelemy | College of Science (utah.edu) and article "Ramón Barthelemy wins 2023 LGBTQ+ Educator of the Year" here: Ramón Barthelemy Out to Innovate | College of Science (utah.edu)
Event Location:
HENN 201
Event Time:
Thursday, September 26, 2024 | 10:00 am - 11:00 am
Event Location:
AMPEL Rm 311
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2024-09-26T10:00:00
2024-09-26T11:00:00
Impact of Josephson junction materials on the performance of superconducting qubits
Event Information:
Superconducting qubits are a leading modality for quantum computing, offering a favorable balance between coherence, gate times, scalability, and fidelity. I will explore the interplay between materials science and qubit performance, with a particular focus on how the materials used in Josephson junctions (JJs) affect qubit behavior. The frequency of a qubit is largely determined by the properties of JJs, which typically consist of amorphous oxide tunnel barriers. These barriers are also the likely location of most two-level systems (TLS) defects. Recently, we discovered an Alternating-Bias Assisted Annealing (ABAA) process that enables us to fine-tune JJs to achieve the desired frequency. Characterizing these ABAA post-processed JJs provides insight into the structural and chemical bonding uniformity of the amorphous oxides after ABAA processing, as well as the impact on qubit performance and TLS density.
Event Location:
AMPEL Rm 311
Event Time:
Wednesday, September 25, 2024 | 12:00 pm - 2:00 pm
Event Location:
Zoom https://ubc.zoom.us/j/69727529419?pwd=8tzHM4QhGjNpV26SgpqRhuEfAqLfyb.1
Meeting ID: 697 2752 9419
Passcode: 501860
Meeting ID: 697 2752 9419
Passcode: 501860
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2024-09-25T12:00:00
2024-09-25T14:00:00
Predictive Metrics for Moist Desquamation in Treatment Planning for Breast Radiotherapy
Event Information:
Abstract: The objective of this thesis was to establish techniques for predicting and modelling moist desquamation (MD). The work in this thesis is based on the clinical studies of the novel Carbon Fibre Adjustable Reusable Accessory (CARA) breast support device. The epidermal dose measurements, treatment plans, and skin assessments from clinical studies of the CARA device were used to develop models to be applied during treatment planning to reduce the occurrence of MD in breast radiotherapy.
In the first study of this thesis, in vivo film dosimetry was used to establish a relationship between the epidermal surface area receiving various levels of radiation dose and the corresponding skin reactions.
The results of this study indicated potential dose-area based constraints on the skin for use during treatment planning.
For the second study, the in vivo film dosimetry was compared against the Eclipse(Varian Medical Systems) treatment planning system’s Analytical Anisotropic Algorithm (AAA) and AcurosXB (AXB) dose calculation algorithms. This study produced recommendations for skin rind definitions for the two dose calculation algorithms to improve consistency in epidermal dose reporting.
In the final study, a metric was developed to predict MD based on the spatial distribution of dose across the skin. This metric maps the risk of MD across the skin’s surface based on the treatment planning system’s skin dose calculations. The predictive model was validated against a second dataset, and showed promise in its performance.
Event Location:
Zoom https://ubc.zoom.us/j/69727529419?pwd=8tzHM4QhGjNpV26SgpqRhuEfAqLfyb.1
Meeting ID: 697 2752 9419
Passcode: 501860
Event Time:
Tuesday, September 24, 2024 | 4:00 pm - 5:00 pm
Event Location:
HENN 318
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2024-09-24T16:00:00
2024-09-24T17:00:00
Constraints on Quantum Gravity
Event Information:
We welcome you to our new Pioneers in Theoretical Physics Colloqium Series, starting this Fall, 2024.
On September 24th, we present Hirosi Ooguri, Fred Kavli Professor of Theoretical Physics & Mathematics, founding Director of the Walter Burke Institute for Theoretical Physics at the California Institute of Technology, and University Professor at the University of Tokyo.
Abstract:
Superstring theory is the best candidate for the ultimate unification of general relativity and quantum mechanics. Although predictions of the theory are typically made at extremely high energies and beyond the reach of current experiments and observations, several non-trivial constraints have been found on its low-energy effective theory. Because of the unusual ultraviolet behavior of gravitational theory, the standard argument for the separation of scales does not work for gravity, leading to robust low-energy predictions of consistency requirements at high energy. For gravitational theories in asymptotically anti-de Sitter spacetimes, we can formulate such constraints and aim to prove or falsify them using the AdS/CFT correspondence. I will review recent progress in this approach. In particular, I will prove the absence of global symmetry in quantum gravity (based on my work with Daniel Harlow) and a part of the distance conjecture in three dimensions (based on my work with Yifan Wang) and discuss the consequences of these constraints.
Bio:
Ooguri studies quantum field theory, quantum gravity, and string theory. He explores mathematical structures in these theories and uses them to develop new theoretical tools for solving fundamental questions in physics. His work in physics has also inspired progress in mathematics.
Links:
Ooguri's Caltech faculty page
Youtube playlist for Hirosi Ooguri's lectures on Topological String Theory (3 lectures)
Youtube playlist for Hirosi Ooguri science lectures
Event Location:
HENN 318
Event Time:
Monday, September 23, 2024 | 4:00 pm - 5:00 pm
Event Location:
HENN 318
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2024-09-23T16:00:00
2024-09-23T17:00:00
Probing the Limits of Black Hole Feedback in the Most Massive Galaxies
Event Information:
Abstract:
In the past several decades it has become clear that mechanical (radio-mode) feedback from supermassive blackholes is necessary to moderate the growth of the most massive galaxies in which they reside. In particular, in the cores of galaxy clusters, the evolution of giant elliptical galaxies appear to be primarily governed by black hole feedback. Despite its apparent importance, our understanding of how feedback works is woefully incomplete, particularly when it comes to mechanical or radio-mode feedback. In this talk I will discuss two directions that we are pursuing to understand the balance between cooling and feedback in galaxy cluster cores: (i) identifying systems for which feedback appears to not work, in an effort to understand the limitations and failure modes of the feedback/cooling cycle, and (ii) searching for evidence of AGN feedback in the cores of the most distant galaxy clusters. All of these efforts require the use of data from a variety of X-ray, optical, mm-wave, and radio telescopes, including Chandra, Hubble, James Webb, and the South Pole Telescope.
Bio:
Michael McDonald is an Associate Professor of Physics at the Massachusetts Institute for Technology's Kavli Institute for Astrophysics and Space Research. He obtained his BScH and MSc degrees in Physics at Queen's University in Canada, and his PhD in Astronomy at the University of Maryland in College Park, MD. Michael spent three years as a Hubble Fellow at MIT, before being hired as an Assistant Professor in July 2015.
His research focuses on the co-evolution of massive galaxies and their super-massive black holes in the rich cluster environment. This research involves the discovery and study of the most distant assemblies of galaxies alongside detailed analyses of the complex interplay between gas, galaxies, and blackholes in the closest, most massive systems. He uses of a wide variety of ground- and space-based observatories, including (but not limited to) the Hubble and Chandra space telescopes, and the Magellan and ALMA telescopes located in Chile.
Learn More:
View Michael's MIT faculty webpage here: Michael A. McDonald » MIT Physics and personal website here: Michael McDonald - Associate Professor - MIT Kavli Institute for Astrophysics and Space Research
See Michael's Kavli Institute faculty page here: Michael McDonald - MIT Kavli Institute
MIT News: Research pulled Michael McDonald in and it won’t let go | MIT News | Massachusetts Institute of Technology
What is a supermassive black hole? Supermassive black holes: Characteristics and formation | Space
NASA animation on black holes: NASA Animation Sizes Up the Universe’s Biggest Black Holes - NASA
Event Location:
HENN 318
Event Time:
Monday, September 23, 2024 | 2:30 pm - 3:30 pm
Event Location:
HENN318
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2024-09-23T14:30:00
2024-09-23T15:30:00
PHAS Monday Tea
Event Information:
Welcome everyone to Monday Tea!
This is a weekly event for students, staff and faculty to meet new-to-you colleagues, catch up with your community and to learn about what's happening in the PHAS Department.
Meet your hosts in the EDI Community Building Working Group:
Jess McIver
Adele Ruosi
Megan Bingham
Evan Goetz
Mona Berciu
Howard Li
Mandana Amiri
See you there!
Event Location:
HENN318
Event Time:
Thursday, September 19, 2024 | 4:00 pm - 5:00 pm
Event Location:
HENN 201
Add to Calendar
2024-09-19T16:00:00
2024-09-19T17:00:00
Polarized Radiation from X-Ray Pulsars
Event Information:
Abstract:
With the launch of the Imaging X-ray Polarimetry Explorer (IXPE) at the end of 2021, we have entered the era of X-ray polarization. IXPE is more than one thousand times more sensitive that previous observatories giving us "first (polarized) light" images of hundreds of X-ray sources. Looking as these objects in an essentially new way for the very first time has been exhilarating. After highlighting many of the key observations of IXPE, I will focus in particular on the observations of accreting X-ray pulsars which despite complicated magnetic field and emission geometries exhibit very simple changes in the polarization direction as the stars rotate. This straightforward evolution with spin results from the first (yet still unverified) prediction of QED that a magnetic field even in vacuum induces an index of refraction: vacuum birefringence.
Bio:
I am currently acting PHAS Department Head, professor at the University of British Columbia and a Canada Research Chair in Neutron Stars and Black Holes. My recent research has focused on compact objects: white dwarfs, neutron stars and black holes. These are the most extreme objects in the universe since the Big Bang. Astrophysicists think that they provide the power behind quasars and gamma-ray bursts, the brightest objects in the recent universe.
To put it concisely I study stars, white dwarfs neutron stars and black holes from an astrophysical perspective. Because I am a theorist I focus what these objects can tell us about fundamental physics and how our current knowledge or speculation about fundamental physics can help us understand these phenomena.
The areas of physics that my research sometimes covers include:
* High-energy astrophysics* Nuclear physics* High-energy physics (particle physics)* General relativity* Cosmology* Condensed matter physics* Atomic physics* Classical dynamics
Education
Doctoral Degree University of California at Santa Cruz, 1998Employment HistoryHead, Department of Physics and Astronomy, University of British Columbia, January 2024-Professor, Department of Physics and Astronomy, University of British Columbia, July 2013-Associate Professor, Department of Physics and Astronomy, University of British Columbia, July 2008-June 2013Assistant Professor, Department of Physics and Astronomy, University of British Columbia, July 2003-June 2008Chandra Fellow, Theoretical Astrophysics Division, Harvard-Smithsonian Center for Astrophysics, September 2000-July 2003Lee A. DuBridge Postdoctoral Fellow in Theoretical Astrophysics, California Institute of Technology, January 1998-August 2000Visiting Researcher, The Central Astronomical Observatory at Pulkovo, Saint Petersburg, Russia, June 1992-September 1992Research Assistant, National Astronomical and Ionospheric Center, Arecibo, Puerto Rico, June 1991-August 1991Research Assistant, Princeton University Observatory, Princeton, New Jersey, June 1989-September 1989
Learn More:
See Jeremy's homepage on the Stellar and High-Energy Astrophysics at UBC website: Jeremy Heyl (coolpulsars.org)
See Jeremy's faculty homepage: heyl | UBC Physics & Astronomy
UBC News: Dr. Jeremy Heyl appointed head, Physics and Astronomy | UBC Science
UBC Expert profiles: Jeremy Heyl, AB (Princeton), MSc (Cambridge), PhD (UCSC) (ubc.ca)
See NASA's webpage on the Imagining X-ray Polarimetry Explorer (IXPE): Imaging X-ray Polarimetry Explorer (IXPE) - NASA
Find NASA articles on pulsars here: 428 Search Results for "pulsar" (nasa.gov)
Event Location:
HENN 201
Event Time:
Thursday, September 19, 2024 | 10:00 am - 11:00 am
Event Location:
AMPEL 311
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2024-09-19T10:00:00
2024-09-19T11:00:00
Quantum Anomalous Hall Effects in Rhombohedral Graphene Moiré Structures
Event Information:
Abstract:
A recent series of experiments in two-dimensional moiré materials have discovered the physics of quantum Hall effect in the absence of an external magnetic field. These so-called “(Integer/Fractional) Quantum Anomalous Hall” phases have been observed in twisted transition metal dichalcogenide MoTe2 moiré heterostructure, as well as more recently in pentalayer rhombohedral graphene aligned with a hexagonal Boron-Nitride (hBN) substrate. Unlike the standard theoretical framework of the quantum Hall effect, where one has a flat band at the single-particle level, these discoveries provide a fertile ground for exploring the minimal conditions that are required to realize and stabilize such exotic phases of matter. In this talk, I will examine the microscopic origin of both the integer and fractional QAH phases in N-layer graphene aligned with hBN through a combination of Hartree-Fock methods and Exact Diagonalization. I will also discuss the delicate role of the moiré superlattice potential in determining the ultimate ground state in strongly-correlated two-dimensional moiré materials. Time-permitting, I will also briefly touch on the phenomenology of the recently observed extended quantum anomalous Hall effect in pentalayer graphene aligned with hBN.
Bio:
Adarsh completed his undergraduate degree at the University of Waterloo, and his PhD at the University of Toronto under the supervision of Yong-Baek Kim in 2021. He was a postdoctoral research associate from 2021—2024 at the Massachusetts Institute of Technology working with Senthil Todadri.
Event Location:
AMPEL 311
Event Time:
Wednesday, September 18, 2024 | 1:30 pm - 3:30 pm
Event Location:
Henn 318
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2024-09-18T13:30:00
2024-09-18T15:30:00
Electrodynamics of Non-topological Solitons
Event Information:
In this thesis, we study a class of non-topological solitons known as "Q-balls" which arise in complex scalar field theories with U(1) symmetry. We focus on the case where the U(1) symmetry is gauged and the theory admits a coupling to electromagnetism; the corresponding solitons are known as "gauged Q-balls". Using numerical simulations, we examine the dynamical behaviour of these objects in various scenarios. First, we investigate the classical stability of gauged Q-balls under assumptions of axial symmetry. Considering two different forms for the scalar field potential, we find evidence for gauged Q-ball configurations which remain stable with respect to axisymmetric perturbations of the fields. We also find evidence for unstable configurations which are quickly destroyed in response to the perturbations (for example, through dispersal of the fields or via fragmentation into smaller structures). Next, we investigate head-on collisions of gauged Q-balls at relativistic velocities. We test the effects of the electromagnetic coupling strength, initial velocity, relative phase, and relative charge of the colliding binary on the outcome of the collision. Depending on the values of these parameters, we observe a variety of distinct phenomena such as gauged Q-ball mergers, fragmentation, charge transfer, charge annihilation, Q-ring formation, and electromagnetic radiation production. Finally, we investigate the dynamics of gauged Q-balls using fully three-dimensional numerical simulations. Extending the previous analyses, we find evidence for configurations which remain classically stable against generic perturbations in three spatial dimensions. We also consider off-axis collisions of gauged Q-balls and find that the impact parameter can play a significant role in determining the outcome of the collision. Together, these results address several key questions about the dynamics of non-topological solitons in general and the stability of gauged Q-balls in particular.
Event Location:
Henn 318
Event Time:
Wednesday, September 18, 2024 | 10:00 am - 12:00 pm
Event Location:
Henn 309
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2024-09-18T10:00:00
2024-09-18T12:00:00
New Tricks for Old Stars: Studying Compact Objects Through Novel Methodologies in Timing, Energy and Imaging
Event Information:
To understand astronomical objects and their environments, it is essential to study their behavior across time, energy and space. For compact objects, these analyses provide a unique window into physics in extreme environments, probing transient behavior, accretion processes, and tests of spacetime and gravity in the high field regime. In this thesis, I present novel approaches to revolutionize timing and spectral analysis and imaging with polarimetry in astronomy. I first present two novel methodologies for astronomical timing analysis: 1) Wiener Deconvolution to resolve the response function generating time lags across different energy bands and 2) Mutual Information as a powerful tool to identify time lags without assuming underlying linearity. I establish methodological framework and demonstrate efficacy of methodologies through toy models for generalized utilization of astronomical timing and lag analysis. I then present the results of novel methodologies applied to radio data from the black hole binary MAXI J1820+070. These approaches not only help in identifying time lags with much higher accuracy and precision, but also reveal numerous previously undetected lags, offering new insights into how the compact jet in MAXI J1820+070 behaves across different energies. I then extend the astronomical application of Wiener Deconvolution to 2D, enabling estimates of the first ever high resolution X-ray polarimetry images, and present preliminary results for the Supernova Remnant Cas A. Finally, I explore magnetar spectral line analysis and modeling, and show how we can learn about the behaviour of magnetic fields at their most intense through spectral lines detected from magnetars with current and future detectors.
Event Location:
Henn 309
Event Time:
Monday, September 16, 2024 | 4:00 pm - 5:00 pm
Event Location:
HENN 318
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2024-09-16T16:00:00
2024-09-16T17:00:00
Roadmap to a compendium of supermassive black hole images
Event Information:
Abstract:
Following the transformational science enabled by the Event Horizon Telescope, we now focus on expanding the parameter space in terms of mass, spin and the role of magnetic field in extreme gravitational environment. It is thus imperative that imaging the silhouette of several black holes, beyond SgrA* and M87*, will provide vital constraints that will also probe the nature of (non-) General Relativity on a cosmological scale. I will present an overview of the fundamental physics that goes into this study from a multiwavelength perspective while also referring to an ongoing study with the EHT to image the photon rings and accretion flows of more AGNs in the nearby Universe. I will also show how the next generation EHT observations both from ground and space can be fundamental in this endeavour.
Bio:
Postdoctoral Researcher Venkatessh Ramakrishnan works at both the Finnish Centre for Astronomy with ESO and Aalto University’s Metsähovi Radio Observatory.
Links:
View his LinkedIn profile page
Aalto University Researchers' bio: Researchers from Aalto University, University of Turku, and Finnish Centre for Astronomy with ESO participated in the project taking a photo of the black hole at the centre of our galaxy
University of Turku (Finland) publications page for Venkatessh Ramakrishnan
Article: University of Turku (Finland): Scientists reveal new images of a black hole - Proof of a persistent black hole shadow
Article: Recognition from the Senate of Chile and the University of Concepción for Dr. Ramakrishnan's work on black holes
Event Location:
HENN 318
Event Time:
Monday, September 16, 2024 | 2:30 pm - 3:30 pm
Event Location:
HENN 318
Add to Calendar
2024-09-16T14:30:00
2024-09-16T15:30:00
PHAS EDI Committee Monday Tea
Event Information:
Welcome everyone to Monday Tea!
This is a weekly event for students, staff and faculty to meet new-to-you colleagues, catch up with your community and to learn about what's happening in the PHAS Department.
Meet your hosts in the EDI Community Building Working Group:
Jess McIver
Adele Ruosi
Megan Bingham
Evan Goetz
Mona Berciu
Howard Li
Mandana Amiri
Pedro Villalba Gonzalez
See you there!
Event Location:
HENN 318