New start date of Fall 2020 semester.

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.…

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. …

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.…

Progress in low energy nuclear reaction measurements

August Gula & Shahina
Physics Graduate Students
University of Notre Dame

Hosted by Prof. Wiescher

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