Benjamin Lev [Stanford]

Abstract: Spin glasses are canonical examples of complex matter and form a basis for describing artificial neural networks.  Repeatable control over microscopic degrees of freedom might open a new window into their structure and dynamics.  I will present how we achieved this at the atomic level using a quantum-optical system comprised of ultracold gases of atoms coupled via photons resonating within multimode cavities.  The controllability provided by this new spin glass system has allowed us to directly measure replica symmetry breaking, yielding the first direct observation of ultrametricity in a physical system.  We use this spin glass to realize an associative memory with a capacity exceeding that of the Hopfield model. Recently, we have upgraded our system to enable the imaging of real-time spin dynamics. I will present some of our first spin glass movies showing the emergence of ultrametric landscape fragmenting.