JILA X317

Abstract

Abstract: Gauge theories form the foundation of modern physics, with applications ranging from early-universe cosmology and heavy-ion collisions to condensed matter systems. However, simulating the real-time dynamics of such quantum many-body systems on classical computers is fraught with difficulties, motivating the pursuit of alternative venues. I will present recent experiments where we employ a large-scale Bose-Hubbard quantum simulator to emulate a U(1) lattice gauge theory, which couples charged matter fields through dynamical gauge fields.

Seeing small things takes bright lights and great optics. But you still have to see something. This talk will discuss detectors for electron and X-ray microscopies: how they work, what are they challenges, and where are the opportunities. The competition is intense: the human eye has ~108 ‘pixels’ and a dynamic range of ~104 (and has a direct connection to a built-in neural processor). No camera today can match these specs (although we are getting close).

As a follow-up to Seminar I, I will discuss specific examples of fs UPS and photovoltage experiments on industrially relevant materials and stacks. Aside from single crystal Si wafers, virtually all materials found in MOS devices, photovoltaics, oxides, organic films (OLEDs, resists) and phase change materials, are polycrystalline or amorphous. Angle integrated UPS provides high count rates that increase sensitivity useful for identifying defect state densities in materials.

CU Boulder · JILA X317 | UC Berkeley · Birge 468 Critical to the design and development of present and future semiconductor and quantum devices is the full understanding of the electronic structure of the materials that comprise the complex functional stacks in a non-destructive way. In Seminars I and II, I will describe the application of femtosecond ultraviolet photoelectron and photovoltage spectroscopy (fs UPPS) to fully characterize the electronic structure of industrially important materials and devices.

Abstract: In this talk I present a method to solve the equations of motion of open quantum many-body systems. It is based on a combination of generalized wave function trajectories and matrix product states. More specifically, we developed an adaptive quantum stochastic propagator, which minimizes the expected entanglement in the many-body quantum state, thus minimizing the computational cost of the matrix product state representation of quantum trajectories.