The talk has been rescheduled for April 22


Prof. Jordy de Vries, University of
Massachusetts Amherst

Neutrinoless double beta decay in effective field theory

Next-generation neutrinoless double-beta decay (0nu2beta) experiments aim to discover lepton number violation in order to shed light on the nature of neutrino masses. A non-zero signal would have profound implications by demonstrating the existence of elementary Majorana particles and possibly pointing towards a solution of matter-antimatter asymmetry in the universe. However, the interpretation of the experimental signal (or lack thereof) requires care as complicated hadronic and nuclear input is required to connect the experimental data to a fundamental description of lepton-number violation. In this talk, I use effective field theories to connect 0nu2beta measurements to the fundamental lepton-number-violating source. In particular, I will argue that interpretation in terms of a light Majorana neutrino mass is more complicated than normally considered, and a new leading contributions must be included.

Dr. Andrew Millis, Center for Computational Quantum Physics, The Flatiron Institute and Department of Physics, Columbia University

Meeting Dirac's Challenge:
From Quantum Entanglement to Materials Theory


About 90 years ago, P. A. M. Dirac established the foundations of many-body quantum mechanics. Summarizing, he wrote ``The underlying physical laws necessary for the mathematical theory of a large part of physics and the whole of chemistry are thus completely known, and the difficulty is only that the exact application of these laws leads to equations much too complicated to be soluble. It therefore becomes desirable that approximate practical methods of applying quantum mechanics should be developed, which can lead to an explanation of the main features of complex atomic systems without too much computation.'' Meeting Dirac's challenge, in other words developing approximate practical methods of determining the properties of interacting many-electron systems, so as to predict e.g. which materials will be novel magnets or high transition temperature superconductors, is one of the grand challenges of modern science. Recent progress has been enabled by remarkable developments in ideas, algorithms and computational power. The interplay between theoretical materials science and research into the fundamental phenomenon of quantum mechanical entanglement, has been crucial to progress in both fields. In this talk I will give an overview of modern quantum many-body theory, outlining the difficulties, describing some recent successes, and presenting a vision for the future.


Friday, March 15, 2019
3:30 p.m.
Gant Science Complex
Physics, Room GW-38

Refreshments will be served prior to the talk at 2:30 in room GW-103

Prof. Alan Wuosmaa, Department of Physics, University of Connecticut

The Structure of "Exotic" Nuclei

Atoms you can't dig out of the ground, and why you should care about them.

Nuclear physicists developed a basic understanding of the properties of atomic nuclei many decades ago, and that understanding has evolved to the point where the structure of stable or near-stable nuclei is reasonably well understood through a combination of modeling, theory and experiment. The theories used to explain stable and near-stable radioactive nuclei, however, are not well tested for nuclei that possess a large imbalance in the numbers of protons and neutrons that makes them behave very differently than stable nuclei. Such unstable nuclei are not typically present on Earth, however play a very significant role in violent astrophysical events that are responsible for the formation of many of the elements that are found in nature. I will describe some of the characteristics that make such nuclei "exotic," and present some new experimental methods that are being used to provide data that can help understand the properties of these systems that can be used to guide new, modern theories of nuclear structure.

Dr. Adam Summers, Department of Physics, Kansas State University


Ultrafast, Strong-Field Investigation of Nanosystems


Here I present work investigating the evolution of various nanosystems in extremely intense, ultrafast laser pulses. We study the dynamical processes initiated in these nanosystems over five order of magnitude of peak laser intensity, from 10^10 W/cm2 to 10^15 W/cm2. Specific processes include: thermal evolution and damage of nanowires under irradiation of a train of intense pulses, photoelectron reqscattering on the surface of nanoparticles, plasmonic enhancements of photoionization and the ultrafast formation of nanoplasmas from nanoparticles.

Multimodal Spectroscopies of Correlated Materials"
Dr Ilya Drozdov,
Brookhaven National Laboratory


In this talk Ilya will present the ongoing work, plans and past results on spectroscopy of correlated oxides. Ilya is a part of the BNL team building a unique capability mergin ARPES, local spectroscopy and MBE growth at BNL. The talk will highlight the past work and present new directions.

Dr. Catherine Kealhofer,
Department of Physics,
Williams College

Generating and controlling ultrafast electron pulses for time-resolved electron diffraction


Ultrafast electron diffraction (UED) is a powerful technique that lets us measure the positions of atoms in a crystal as they evolve during chemical and physical transformations. These measurements can give insight into how materials work on a microscopic level as well as guide the design of devices that respond on fast timescales. For some time, the best-available time resolution in UED has hovered around 100 fs (1 fs =10-15 s), just shy of the 10 fs resolution required to see the fastest atomic motions. In my talk, I'll explain how ultrafast electron diffraction works and why it's challenging to break the 100-fs resolution barrier. I'll show experimental results on a recent technique that uses terahertz electromagnetic fields to compress electron pulses in time. This technique has the potential to improve the resolution of UED below 100 fs and maybe even below ~1 fs, into the regime of electronic dynamics. The talk will also introduce ultrafast electron sources based on laser-triggered electron emission from nanometrically sharp metal tips. Not only is the physics of ultrafast electron emission in this system very rich, but the extraordinarily small source size in comparison with typical ultrafast flat photocathode sources can dramatically improve the beam quality, leading to smaller probe sizes, higher quality diffraction patterns, and enabling new techniques like ultrafast electron holography.

Prof. Stephen Pate,
New Mexico State University

Exploring the Axial Structure of the Nucleon

Modern electron-scattering facilities, such as CEBAF at Jefferson Lab and MAMI at Mainz, have made possible a deep exploration of the electric and magnetic distributions in the nucleon, via measurement of the so-called "vector form factors" accessible via elastic electron scattering experiments. Our knowledge of the "axial form factor", on the other hand, has lagged behind because this sector, related to angular momentum, is suppressed in electron scattering and is more easily explored in elastic and quasi-elastic neutrino scattering. Of particular interest is the isolation of the strange quark contribution to the nucleon axial form factor, as this is related to the strange quark contribution to the nucleon spin, a quantity which has so far resisted a definitive determination. The MicroBooNE experiment at Fermilab is uniquely suited to explore the axial form factor through both neutral-current and charge-current neutrino interactions. I'll present an overview of the general MicroBooNE physics program and an in-depth look at our current status with respect to the axial form factor determination.

Prof. Robin Cote, Department of Physics, University of Connecticut

AMO Theory at UConn: Ultracold Physics

Whenever a new window of parameters open up in Science, new discoveries follow. Examples range from ultrafast physics with atto-second lasers probing the time scale of electrons' motion, or the Kepler space telescope which allows the discovery of thousands of exo-planets. Another such new regime arises from ultracold temperatures, where the slow motion of particles allow to probe new behaviors, such as Bose-Einstein condensation of atoms or molecules, degenerate Fermi gases, and much more. In this presentation, I will introduce what ultracold AMO physics is, and describe the current research in my group on ultracold Rydberg physics and ultracold chemistry, and their applications to quantum information science and astrophysics.