# News

## General and Physics GRE scores not required for 2020/21 academic year graduate school applicants

### July 15, 2020 • Categories: News

General and subject specific (physics) GRE tests will not be required for graduate student applications for the 2020/21 academic year. This decision was made in light of the ongoing COVID-19 pandemic, and the associated difficulties taking these test, in particular for international applicants.

The department will also review possible permanent changes to the GRE requirements. Recently, the value of the subject GRE test has been called into questions, and many programs have dropped the requirement altogether (see for example the recent article in Physics Today

## Aprahamian appointed to JINR Scientific Council

### July 06, 2020 • Categories: News

The Committee of Plenipotentiaries of the Governments of the Member States of the Joint Institute for Nuclear Research (JINR) has appointed Freimann Professor of Physics Ani Aprahamian as a new member of the JINR Scientific Council. Her appointment runs through the end of its mandate in March 2023.…

## Gear treated with ‘forever chemicals’ poses risk to firefighters

### June 24, 2020 • Categories: News

Graham Peaslee’s team tested more than 30 samples of used and unused PPE from six specialty textile manufacturers in the United States and found them to be treated extensively with PFAS or constructed with fluoropolymers, a type of PFAS used to make textiles oil and water resistant.

## Physics graduate student recognized with 2020 CRC Award for Computational Science and Visualization

### June 15, 2020 • Categories: News

The Department of Physics is proud to announce that graduate student Trevor Sprouse has been recognized with a 2020 Center for Research Computing (CRC) Award for Computational Sciences and Visualization. This award recognizes outstanding contributions in the areas of computational sciences and visualization. Such contributions may include, but are not limited to: 1) applications of high performance computation and/or visualization technology; 2) development of algorithms, codes, software environments or other tools for better using high performance computing and/or visualization.…

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# Events

## 2020 Fall Semester begins

### All Day

New start date of Fall 2020 semester.

## Astrophysics Seminar: Prof. Grant J. Mathews, Center for Astrophysics, University of Notre Dame

### 12:30 PM - 1:30 PM zoom

Cosmic relic supernova neutrinos

Prof. Grant J. Mathews
Center for Astrophysics
University of Notre Dame

The universe is permeated with a diffuse background of cosmic relic neutrinos that records the history of  every supernova that has occurred since the beginning of star formation.  As such this background is a valuable probe of both cosmic history and the physics of supernova explosions.  This talk will  review the computation of and associated uncertainties in the current understanding of the relic neutrino background due to core-collapse supernovae, black hole formation and neutron-star merger events. We consider the current status of uncertainties due to the nuclear equation of state (EoS), the progenitor masses, the source supernova neutrino spectrum, the cosmological star formation rate, the stellar initial mass function, neutrino oscillations, and neutrino self-interactions. We summarize the current viability of future neutrino detectors to distinguish the physics of supernovae via the detected relic supernova neutrino spectrum.…

## Physics Colloquium: Prof. Stacy McGaugh, Case Western Reserve University

### 4:00 PM - 5:00 PM Online streaming

The Acceleration Scale in Galaxy Dynamics

Prof. Stacy McGaugh
Department of Astronomy
Case Western Reserve University

The flat rotation curves of spiral galaxies played an essential role in establishing the dark matter paradigm. There is more to the story: the amplitude of the flat rotation speed correlates with the mass that is observed in stars and gas (the Baryonic Tully-Fisher Relation). The dynamical surface density (including all mass) correlates with that of the stars alone (the Central Density Relation). The total radial force correlates with that predicted by the observed distribution of baryons (the Radial Acceleration Relation). These empirical relations are all connected by a common acceleration scale that is of order 1 Angstrom/s/s. Understanding the origin of this scale is central to solving the missing mass problem. …

## Condensed Matter Seminar: Dr. Manohar Kumar, Aalto University, Finland

### 4:00 PM - 5:00 PM Online streaming

Dr. Manohar Kumar
Research Fellow
Department of Applied Physics
Aalto University, Finland

Particle collider in condensed matter physics for Anyons

Two-dimensional systems at low temperatures and at high magnetic field, can host exotic particles with elementary excitations carrying fractional charge e* = e/q such as in fractional quantum Hall effect 1 . These exotic particles are called anyons, whose quantum statistics are neither bosonic nor fermionic; instead they are predicted to obey fractional statistics 2 . The fractional charge of these anyons has been studied successfully using low frequency shot noise measurement 3,4 . However, no universal method for sensing them unambiguously exists 5 . Also, clear signature of the fractional statistics remains elusive. Here we exploited the Josephson relation of these anyonic states to determine the fractional charge of excited quasiparticles. The microwave photons emitted by voltage biased anyonic system obey the Josephson relation, like superconducting Josephson junction but with the charge q = e* rather than 2e. This provides    direct evidence of fractional charge in fractional quantum Hall effect 6 . Lastly, we also probed the fractional statistics in mesoscopic anyonic collider 7 . Our collision results explicitly extract the quantum phase of \phi = pi/3 for exchange of two anyonic quasiparticles with q = e/3. This is very first smoking gun result on fractional statistics of anyon. This collider geometry could be extended to perform ultimate braiding experiment to realized full potential of special kind of anyon called non-Abelian anyons in topological quantum computation.…

## Nuclear Physics Seminar: August Gula & Shahina, University of Notre Dame

### 4:00 PM - 5:00 PM Bond Hall G09 and zoom

Progress in low energy nuclear reaction measurements

August Gula & Shahina