Talks

CMD SEMINARS: Hydrodynamics from a Holographic Perspective

Many physical systems admit a simplified description of their dynamics at macroscopic scales. This description—hydrodynamics—is governed by a small set of observables, such as conserved quantities. A central challenge in quantum many-body physics is to derive this behavior from microscopic dynamics. I will present a holography-inspired method for studying the dynamics of local operators in 1d spin chains using a (1+1)d auxiliary bulk circuit. The goal is to develop a generic approach to finding the equation of motion for local operators and to show that the appropriate truncation is not necessarily based on operator size. Instead, relaxation on the boundary spin chain sets a natural truncation depth in the bulk, leading to a finite transfer matrix formulation. This truncated transfer matrix provides both a linear equation of motion for bulk operators and a new method for extracting Ruelle–Pollicott resonances. Extracting diffusion constants remains a work in progress. I will present results for two case studies: the mixed-field Ising model and a Floquet circuit with U(1) symmetry.

Gutzwiller Colloquium

Tenure Trek: Navigating Academia Around the World

4:30 - 5:30 pm : colloquium "Search as (quantum) selforganized process" by Prof. Dr. Giovanna Morigi 5:30 - 6:00 pm : a coffee break 6:00 - 7:00 pm: Exploring academic systems, gender representation, and career strategies: insights from internationally experienced PIs, followed by a discussion. Abstract for the colloquium: Efficient retrieval of information is a core operation in the world wide web, is essential for the sustainance of living organism, and is a paradigm for optimization algorithms. Inspired by the food search dynamics of living organisms, we discuss a search on a graph with multiple constraints where the dynamics is a selforganized process resulting from the interplay of coherent dynamics and Gaussian noise. We show that Gaussian noise can be beneficial to the search dynamics leading to significantly faster convergence to the optimal solution. We then analyse how these concepts can be extended to quantum searches, cast in terms of spatial searches on a graph and discuss whether and when the efficiency of noise-assisted quantum searches can outperform the one of unitary protocols.

Colloquium

Colloquium

Tunable Matter -- Many More is More Different

In 1972 Phil Andersen articulated the motto of condensed matter physics as “More is different.” However, for most many-body systems the behavior of a trillion bodies is nearly the same as that of a thousand. Here I argue for a class of condensed matter, “tunable matter," in which many more is different. The ultimate example of tunable matter is the brain, whose cognitive capabilities increase as size increases from 302 neurons (C. Elegans) to a million neurons (honeybees) to 100 billion neurons (humans). I propose that tunable matter provides a unifying conceptual framework for understanding not only a wide range of systems that perform biological functions, but also physical systems capable of being trained to develop special collective behaviors without using a processor.