QUANTUM SPIN DYNAMICS, COHERENCE, AND DISORDER IN DENSE MAGNETIC SYSTEMS
Abstract
The behavior of individual objects such as atoms has been well understood since the early days of quantum mechanics. However, once these objects begin to interact with each other, a broad range of new physical effects emerge that are of interest for both pure research and technology development. A common approach to studying these effects is to adopt a “bottom up” strategy, where experiments begin by taking a set of simple, isolated quantum objects – individual “spins” – letting them interact, and measuring the states of all of the individual elements in order to obtain insights into the collective behavior. This approach allows for very precise measurement and control, but is limited in scale to ensembles of hundreds or perhaps thousands of elements. Here, we instead adopt a “top down” strategy. We start with a large system and, by controllably introducing disorder, enable the system to self-assemble into a collection of interacting elements. The challenges with this approach lie predominately in manipulation and addressability. As there are far too many spins to handle individually, we need overall tuning knobs that tie into the small-scale dynamics and local disorder of sets of spins, as well as high resolution probes sensitive to their collective behavior. We choose a family of magnetic crystals that permit us to take advantage of the ability to tune quantum tunneling via a magnetic field applied perpendicular to the ordering directions of the spins. These materials, with random distribution of spins, naturally provide a wide range of size scales and hence a diverse set of collective behaviors. By driving the systems out of equilibrium, we propose to study the fundamental nature of the spin dynamics, the stability of these driven states, and the interactions of quantum-mechanically coherent clusters of spins with their environment.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 12, 2021
- Source ID
- FA95502010263
Entities
People
- Daniel Silevitch
Organizations
- Air Force Office of Scientific Research
- California Institute of Technology
- United States Air Force