News & Events

Colloquium: Jos Uffink, Philosphy, UMN

Abstract:

Thermodynamics, a venerable physical theory from the 19th century,  is nowadays often regarded as just a limiting case of the various theories in statistical physics in the “thermodynamical limit”;  not as a physical theory on its own.  Nevertheless, there are arguments to take the approach of the 19th century founders of this theory  (Clausius, Kelvin, and Planck a.o.)  seriously even today as thermodynamics is being applied to more exotic objects like black holes. 

I will in this talk review the foundational assumptions of classical thermodynamics and problems and the disputes surrounding them until today.

Colloquium: Raffaella Margutti, U of CA, Berkeley


Abstract: Astronomical transients are signposts of catastrophic events in space, including the most extreme stellar deaths, stellar tidal disruptions by supermassive black holes, and mergers of compact objects. Thanks to new and improved observational facilities we can now sample the night sky with unprecedented temporal cadence and sensitivity across the electromagnetic spectrum and beyond. This effort has led to the discovery of new types of astronomical transients, revolutionized our understanding of phenomena that we thought we already knew, and enabled the first insights into the physics of neutron star mergers with gravitational waves and light. In this talk I will review some very recent developments that resulted from our capability to acquire a truly panchromatic view of transient astrophysical phenomena. I will focus on two key areas of ignorance in the field: (i) What are the progenitors of stellar explosions and what happens in the last centuries before death? (ii) What is the nature of the compact objects produced by these explosions and what happens when compact objects merge? The unique combination of Discovery Power (guaranteed by planned transient surveys across the electromagnetic spectrum, combined with efforts in the realm of artificial intelligence) and Understanding (enabled by multi-messenger observations) is what positions time-domain astrophysics for major advances in the near future.

Colloquium: Irfan Siddiqi, UC Berkley

Abstract:  Quantum mechanics describes the physical world around us with exquisite precision, with no known violations of the theory. Ironically, this precision comes with some additional baggage: the theory permits the existence of a host of complex, delicate entangled states of the physical world, many of which have yet to be produced or observed. The debate of whether their quantum entanglement really captures the fundamental nature of the physical world and is an engineering resource is reaching a critical moment.  Quantum processors with of order 100 qubits based on superconducting circuitry have recently demonstrated computing power on par with the most advanced classical supercomputers for select problems. Current hardware is, however, prone to errors from materials defects, imperfect control systems, and the leakage of quantum information into unwanted modes in the solid-state. I will describe the major decoherence pathways present in state-of-the-art superconducting quantum processors, illustrate techniques to maximize the computing power of imperfect qubits, and highlight recent quantum computations for determining chemical energies, solutions to the transverse-field Ising model, scrambling dynamics in black holes, and nuclear scattering.

Irfan Siddiqi is the Director, Quantum Nanoelectronics Laboratory (QNL) U of CA, Berkeley

Colloquium: Katrin Heitmann, Argonne National Laboratory

Abstract:  Three decades of surveying the sky have culminated in the celebrated cosmological standard model, yet 95% of the mass-energy of the Universe is still a mystery, residing in dark matter and dark energy. To address these mysteries, major cosmological surveys are ongoing and new ones will soon start. There are tremendous modeling and simulation challenges posed by these observations in order to enable the full interpretation of the associated cosmological measurements. In this talk I will discuss recent advances in large-scale simulations on the way to prepare for the arrival of the first exascale supercomputers. I will describe an ambitious end-to-end simulation project that attempts to provide a faithful view of the Universe as seen through the Rubin Observatory's Legacy Survey of Space and Time (LSST). This resulting synthetic sky provides many opportunities for exploring new ways to optimize the science return of LSST.

Colloquium: Pat Kelly, University of Minnesota

Abstract: Massive stars drive the evolution of galaxies through their winds, ionizing radiation, and energetic explosions as supernovae (SNe). We have lacked a means, however, to study massive stars in detail beyond the very nearby universe, because it has not been possible to resolve individual stars in distant galaxies.  Using the Hubble and, very recently, the James Webb Space Telescopes, we have discovered the first set of individual, highly magnified stars at cosmological distances. These become visible due to their extreme magnification by foreground galaxy-cluster gravitational lenses, with additional time-varying contributions from individual objects in the cluster. The fluctuation of their magnification depends upon the constituents of the foreground galaxy cluster, including of its dark matter, which will allow the use of these stars as powerful probes. I will next describe the measurement of a new, independent estimate of the Hubble constant from a multiply imaged, gravitationally lensed supernova (SN), and novel constraints on the radius of an individual red supergiant star at a lookback time of 11.5 Gyrs. Using the current sample of SNe multiply imaged by galaxy clusters, we have inferred a rate of core-collapse SNe at lookback times of 10-12 Gyrs that is in tension with existing constraints. Finally, I will describe the Total-Coverage Ultrafast Response to Binary Mergers Observatory (TURBO), which will enable insights into SN explosions and the mergers of their compact remnants in the nearby universe.

Public Telescope Viewing

Presenter: Derek Perera, John Miller

Topic: Gravitational Lensing

Join us on Friday night for rooftop observing through our historic telescope in the dome of Tate Hall. There will be a presentation followed by outdoor observing (weather-permitting). You will have the chance to observe some of the same celestial objects that have inspired sky-gazers throughout history!

Colloquium: Robert Socolow, Princeton

Abstract: Physics simplifies, often productively. I report on small personal and collaborative contributions to planetary thinking that have a physics style. Among the topics discussed are global stocks and flows of energy and carbon, geophysically closed carbon cycling, global distributions of individual emissions, project-level committed emissions, linkages between nuclear power and nuclear weapons, and energy-efficient buildings. The goal is to persuade physicists to contribute to the creation of a sustainable world through their research and teaching.

 

Public Telescope Viewing

Presenter: Daniel Warshofsky

Topic: A Star's Life

Join us on Friday night for rooftop observing through our historic telescope in the dome of Tate Hall. There will be a presentation followed by outdoor observing (weather-permitting). You will have the chance to observe some of the same celestial objects that have inspired sky-gazers throughout history!

Misel Colloquium: Carlos Frenk

The “Lambda cold dark matter'' (LCDM) cosmological model is one of the great achievements in Physics of the past thirty years. Theoretical predictions formulated in the 1980s turned out to agree remarkably well with measurements, performed decades later, of the galaxy distribution and the temperature structure of the cosmic microwave background radiation. Yet, these successes do not inform us directly about the nature of the dark matter.  This manifests itself most clearly on subgalactic scales, including the dwarf satellite galaxies of the Milky Way and especially less massive dark matter halos, too small to have made a galaxy.  Apparent contradictions between the predictions from cosmological simulations and observations have led to the perception of a “small-scale crisis” for LCDM. I will argue that this perception stems from an inappropriate application of the simulations and that, in fact, the theory is entirely consistent with available data. I will contrast the predictions of LCDM with those of the interesting alternative of warm dark matter and show how forthcoming gravitational lensing and gamma-ray data can conclusively distinguish between the two.

 

2022 Misel Family Lecture: Carlos Frenk

Research: Professor Frenk is Director of the Institute for Computational Cosmology and the Ogden Professor in the Department of Physics at Durham University. His research is focused on extragalactic astronomy and cosmology, fluid dynamics, mathematical modeling, and supercomputer simulations.

The William I. Fine Theoretical Physics Institute is proud to host the 15th Annual Misel Family Lecture. This lecture is FREE AND OPEN TO THE PUBLIC. Questions? Please contact us at ftpi@umn.edu or 612-625-6055. We look forward to seeing you there!

Abstract: This lecture is about a future technology, quantum computing, which uses known laws of quantum physics to compute in new ways. Within this technology challenge are at least two profound questions in basic science: which problems can be sped up with a quantum computer, and how can inadvertent measurement be avoided. After a few introductory comments about the first question, this lecture will concern mostly the second question, and will explore some options and the challenges of each.

Read more about Professor Frenk on his Durham University profile and Wikipedia page.

Registration for the lecture is encouraged but not required

School News

John Broadhurst

John Broadhurst, 1935 - 2023

Professor Emeritus John Broadhurst of the School of Physics and Astronomy passed away on October 17 th , 2023. He was 88 years old. John was born in England in 1935 and received all of his degrees
Fiona Burnell

Burnell elected APS Fellow

Associate Professor Fiona Burnell of the School of Physics and Astronomy has been elected a Fellow of the American Physical Society. 
Michael Wilking

Moving Target: New Faculty member does neutrino research with a twist

Professor Michael Wilking is a new faculty member in high energy physics. Wilking’s research is focused on neutrinos and he is a member of several international neutrino collaborations, including
Professor Lindsay Glesener presenting a lecture

Three faculty positions open at the School

The School of Physics and Astronomy invites applications for three tenure track or tenured faculty positions in Experimental Particle Physics, Theoretical Condensed Matter Physics, and Experimental
On the left a snapshot of a lion taken at night, on the  right a head and shoulders picture of Sarah Huebner

Huebner receives Innovation Award

Dr. Sarah Huebner of the School of Physics and Astronomy has received the Innovation Impact Case Award for her project “Citizen Science and Artificial Intelligence Combined to Conserve Earth’s
Ben Margalit

Catching lightning in a bottle: new faculty member studies the physics of transient events

Ben Margalit is a new faculty member in the School and a theoretical astrophysicist who studies the fundamental physics of star explosions, collisions and other examples of intergalactic violence
Raymond Co, Zhen Liu and Kun-Feng Lyu

Liu group helps expand the search for new particle

A team led by Assistant Professor Zhen Liu of the School of Physics and Astronomy has discovered a new way to search for axions, hypothetical particles that could help solve some of nature’s most
Computer chip in Professor Pribiag's lab

Pribiag group creates new superconducting diode that could improve performance of quantum computers and artificial intelligence

Professor Vlad Pribiag of the School of Physics and Astronomy led a team that developed a more energy-efficient, tunable superconducting diode—a promising component for future electronic devices—that
Supernova telescope image

Kelly leads first-of-its-kind measurement of the Universe’s expansion rate

Assistant Professor Patrick Kelly of the School of Physics and Astronomy led a team which used a first-of-its-kind technique to measure the expansion rate of the Universe, providing insight that
Fellowship and awards title

2023 Graduate Awards and Fellowships

There are 14 graduate award and fellowship recipients in the School for 2021.

School of Physics and Astronomy Seminar Calendar