Spring 2020

Rings and tunnel junctions: Quantum mechanics on a circle

Speaker(s): 
Arthur Davidson
Dates: 
Thursday, April 2, 2020 - 4:00pm

We show by standard quantum principles that two circuits, a small tunnel junction and a small metal loop with an electron, are related by a gauge transformation.  We show further that this same transform prevents momentum eigenfunctions from having gauge invariant de Broglie wave lengths around a ring. Thus persistent current on a metal ring and the Coulomb blockade on a small tunnel junction seem to be the same dynamical theory based on discontinuous Bloch waves on the perimeter of a circle. This is historically an area of simple quantum circuits where the principle of gauge invariance...

Move aside sliced bread, we've got a new phase of matter

  • By Jenny Stein
  • 18 February 2020

A research team led by professors from the University of Pittsburgh Department of Physics and Astronomy has announced the discovery of a new electronic state of matter. PQI members Jeremy Levy, Patrick Irvin, David Pekker, and Roger Mong are coauthors of the paper "Pascal conductance series in ballistic one-dimensional LaAIO3/SrTiO3 channels." The research focuses on measurements in one-dimensional conducting systems where electrons are found to travel without scattering in groups of two or more at a time, rather than individually. The study was published in Science on Feb. 14. Jeremy also breaks down the scientific concepts and guides the readers through their research in the following video.

Electron Dynamics in Materials from First Principles

Speaker(s): 
Marco Bernardi
Dates: 
Tuesday, March 24, 2020 - 4:00pm

Recent progress in combining density functional theory and related methods with the Boltzmann transport equation are enabling spectacular advances in computing electron dynamics in materials from first principles. The interaction between electrons and lattice vibrations (phonons) plays a central role as it governs carrier dynamics near room temperature and at low energy. I will present our recently developed methods to compute electron-phonon scattering processes from first principles, and show how these advances enable calculations of electron dynamics in materials, including: 1) First-...

Hydrogen peroxide on the go

  • By Jenny Stein
  • 12 February 2020

The big brown bottle of hydrogen peroxide (H2O2) is a staple of the modern medicine cabinet, always on hand for first aid needs. Lesser known uses of hydrogen peroxide include disinfecting hospital equipment and fueling spacecraft. Yet as common and beneficial of a substance as it is, hydrogen peroxide is surprisingly hard to produce and transport. Currently, hydrogen peroxide is made through what’s known as the “anthraquinone process.” This method is energy-intense, requires large-scale production, and produces large quantities of carbon dioxide (CO2) as a byproduct. While directly reacting hydrogen and oxygen to make hydrogen peroxide would be ideal, thermodynamics prefers to form the more stable water (H2O) over hydrogen peroxide.

So the challenge becomes: does a material exist that can be used to selectively, reliably, and efficiently form hydrogen peroxide whenever and wherever it’s needed, so that transporting it isn’t necessary? A team of researchers from Carnegie Mellon University has set out to meet that difficult challenge. Associate Professors Venkat Viswanathan (mechanical engineering) and Tzahi Cohen-Karni (biomedical engineering/materials science and engineering) are leading an effort to develop a cheap, renewable, and sustainable method of creating hydrogen peroxide. The team has published a paper in ACS Catalysis on the work.

Fullerton and Hatridge named 2020 Sloan Research Fellows

  • By Jenny Stein
  • 12 February 2020

A hearty congratulations to both Prof. Susan Fullerton in Pitt Chemical Engineering and Prof. Michael Hatridge in Pitt Physics as recipients of 2020 Sloan Research Fellowships! Awarded annually since 1955, the fellowships honor scholars in the U.S. and Canada whose creativity, leadership, and independent research achievements make them some of the most promising researchers working today. Winners receive $75,000, which may be spent over a two-year term on any expense supportive of their research.

13th Elsevier Distinguished Lecture in Mechanics​​​​​​​: Quantum Information and Deep Learning for Turbulent Combustion Modeling & Simulation

Speaker(s): 
Peyman Givi
Dates: 
Thursday, April 2, 2020 - 10:00am

13th Elsevier Distinguished Lecture in Mechanics

Quantum Information Science (QIS) and Artificial Intelligence (AI) are having a dominant influence in many aspects of life in industrial societies. The importance of these fields to the global economy and security are very well recognized, promoting the rapid growth of the related technologies in the upcoming decades. This growth is fueled by very large investments by many governments and leading industries. An arena in which QIC and AI are being promoted to play a more significant role is combustion. The fact is that...

Studies of Natural and Artificial Photosynthesis

Speaker(s): 
Victor Batista
Dates: 
Thursday, February 27, 2020 - 2:30pm

Research statement: Our research is concerned with the development of rigorous and practical methods for simulations of quantum processes in complex systems as well as with applications studies of photochemical processes in proteins, semiconductor materials, and systems of environmental interest. We have recently made significant progress toward the establishment of rigorous quantum mechanical approaches for describing equilibrium and dynamical properties of complex quantum systems. We are currently investigating how to extend these calculations to investigate quantum mechanical processes...

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