Spring 2020

POSTPONED: Einstein’s Light Quanta : From Millikan to Circuit QED

Douglas Stone
Monday, March 23, 2020 - 4:00pm

Einstein is well known for his rejection of quantum mechanics in the form it emerged from the work of Heisenberg, Born and Schrodinger in 1926.  Much less appreciated are the many seminal contributions he made to quantum theory prior to his final scientific verdict: that the theory was at best incomplete.   His many key conceptual innovations leading to the emergence of modern quantum theory place him as arguably its central figure [1].  In this talk I will focus on his introduction of the idea of quanta of light in 1905, the beginning of the photon concept in physics.  Einstein recognized...

ONLINE: New Surprises in High Tc Tunnel Junctions

Douglas Natelson
Monday, April 13, 2020 - 4:00pm

Abstract: High temperature superconductivity remains one of the major open problems in physics.  It also is connected to another open question:  what is the right way to think about “strange metals”, for which our standard fermi liquid model of metals doesn’t seem to apply?  Atomically precise, epitaxial tunnel junctions are a means to examine these materials in a nominally simple configuration that minimizes disorder and surface effects.  We use c-axis epitaxial junctions to examine tunneling between La(2-x)Sr(x)CuO4 source and drain electrodes separated by a 2 nm barrier...

Revealing the Scaling Properties of Matter Through Low-Dimensional Crystals

Thomas Kempa
Friday, February 28, 2020 - 11:30am

The physical properties of matter change dramatically as atoms assemble into extended solids. Low dimensional crystals could be used to reveal the intricate evolution of material properties across extremes of scale. However, overcoming profound challenges to progress will require methods for systematic and precise control over the size, shape, and structure of these crystals. To this end, we have developed strategies for controlled crystallization of low-dimensional materials and have identified that even subtle tuning of their dimensionality and morphology yields substantial property...

Shining Light on Magnetism: Controlled Magnetic Switching With Ultrafast Optical Pulses

Eric Fullerton
Friday, February 7, 2020 - 11:30am

The possibilities of manipulating magnetization without applied magnetic fields have attracted growing attention over the last two decades. The low-power manipulation of magnetization, preferably at ultra-short time scales, has become a fundamental challenge with implications for future magnetic information storage and memory technologies. I will discuss recent experiments on the optical manipulation of the magnetization of engineered materials and devices using 50-5000 fs optical pulses. We demonstrate that all optical switching can be observed in a broad range of materials and not...

QM simulations to identify improved photovoltaic materials

  • By Jenny Stein
  • 15 January 2020

Noa Marom leads a Carnegie Mellon University team in an Argonne Early Science Project with plans to use Aurora, Argonne's exascale supercomputer, to find materials that can increase the efficiency of solar cells. They use machine learning tools extensively in their research and are working with the developers of BerkeleyGW, SISSO, and Dragonfly software to prepare to run on the Aurora system.

According to Marom, “The goal of our research is to find new materials that make photovoltaic solar cells more efficient. The quest for any new materials that can enable new technologies is challenging. The materials we are researching have unique properties that make them suitable for use in solar cells, and these properties are very rare and difficult to find out of the wide array of possible materials. We are trying to accelerate the process of material discovery through computer simulation on high-performance computers (HPC) using sophisticated quantum-mechanical simulation software and machine learning (ML) tools. We are excited that our project has been accepted as one of the projects that will run on the future Aurora supercomputer as part of the Argonne ESP program. Our multi-institution team is currently modifying algorithms and workflows so they will be able to run on Aurora.”

Conference for Undergraduate Women in Physics

Multiple Speakers
Friday, January 17, 2020 - 12:00pm to Sunday, January 19, 2020 - 3:00pm

APS Conferences for Undergraduate Women in Physics (CUWiP) are three-day regional conferences for undergraduate physics majors held simultaneously around the US and Canada. Their goal is to empower undergraduate women and gender minorities in their pursuits and aspirations in the field of physics by providing them with an opportunity to connect with peers and leaders, learn strategies for success, and be inspired by experts.

The 2020 program in Pittsburgh will include research talks, panel discussions...