PQI Seminar: Dr. David Wallace

Dr. Dave Wallace from the University of Pittsburgh gave a talk titled "What is 'Orthodox' Quantum Mechanics?" in the Pittsburgh Quantum Institute Fall Seminar series on Nov. 12th, 2020.

Abstract: What is called "orthodox'' quantum mechanics, as presented in standard foundational discussions, relies on two substantive assumptions --- the projection postulate and the eigenvalue-eigenvector link --- that do not in fact play any part in practical applications of quantum mechanics. I argue for this conclusion on a number of grounds, but primarily on the grounds that the projection postulate fails correctly to account for repeated, continuous and unsharp measurements (all of which are standard in contemporary physics) and that the eigenvalue-eigenvector link implies that virtually all interesting properties are maximally indefinite pretty much always. I present an alternative way of conceptualizing quantum mechanics that does a better job of representing quantum mechanics as it is actually used, and in particular that eliminates use of either the projection postulate or the eigenvalue-eigenvector link, and I reformulate the quantum measurement problem within this new presentation of orthodoxy.

PQI Seminar: Dr. Chris Lirakis

Dr. Chris Lirakis from IBM-Q gave a talk titled "What does it Take to Build a Quantum Computer" in the Pittsburgh Quantum Institute Fall Seminar series on Oct. 1st, 2020.

Abstract: IBM has been working on realizing a quantum computer since the idea first surfaced in 1982. Early instantiations were photon-based and proved that indeed bit like information could be stored in a quantum state. Since then many different modalities have sprung up, Trapped Ions and Superconducting qubits being the most popular. The IBM systems are on the path to error correction. However, we still have a long way to go. The path to success will be paved by wide scale acceptance and training in these using this new computational paradigm. All manner of expertise will be important on the road to success. Beyond the need for experts in quantum computation, the nation will need experts in mechanical engineering, electrical engineering, computer science and other disciplines. During this talk I will show how IBM is using superconducting technology as quantum bits (qubits) and all of the ancillary technology along with notions of the types of problems we wish to solve. The goal is to show how each of this disciplines can help on the path to large scale system.

PQI Profiles: Hideo Mabuchi

Professor Hideo Mabuchi from Stanford University talks about joining the Caltech faculty straight out of graduate school, coherent Ising machines, and learning to take oneself seriously.

Hideo Mabuchi received an AB in Physics from Princeton and a PhD in Physics from Caltech.  He served as Chair of the Department of Applied Physics at Stanford from 2010-2016.  His early scientific research was focused on understanding open quantum systems, quantum measurement, and the quantum-to-classical transition.  In recent years his research group has turned towards fundamental issues of quantum engineering, such as quantum nonlinear dynamics, quantum feedback control and quantum model reduction.  Along the way his group has also worked substantially on single-molecule biophysics, quantum information science, and quantum materials.  In parallel with directing his group's sponsored research, Hideo has developed a deep personal interest in exploring the interfaces of modern science with traditional craft, aesthetic philosophy and new materialism.  He has been experimenting with novel teaching initiatives to help resurrect the ideals of liberal education in the modern university.

How to Dress a Metal

  • By Jenny Stein
  • 6 May 2020

Research describing how an optical field can modify the electronic properties of a solid was recently published in Nature Communications titled "Coherent multidimensional photoelectron spectroscopy of ultrafast quasiparticle dressing by light", coauthored by Dr. Marcel Reutzel, Hrvoje Petek, and Petek's students Andi Li and Zehua Wang.

Applying intense ultrafast light pulses, which provide a time-periodic electronic potential acting together with the lattice ions, defines the forces experienced by electrons in solids, such as metals and semiconductors, Petek and his coworkers demonstrated that an optical field can transiently, on the 10-14 second time scale, modify (dress) the electronic bands in a metal, potentially changing them from an electron to a hole condition. 

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.