לוח שנה משולב

In this talk, I will present theoretical and computational chemistry approaches to describe excited-states in quantum matter, and predicting emergent states created by external drives. Understanding the role of such light-matter interactions in the regime of correlated electronic systems is of paramount importance to fields of study across chemical and condensed matter physics, and ultrafast dynamics1. The simultaneous contribution of processes that occur on many time and length-scales have remained elusive for state-of-the-art calculations and model Hamiltonian approaches alike, necessitating the development of new methods in computational chemistry. I will discuss our work at the intersection of ab initio cavity quantum-electrodynamics and electronic structure methods to treat electrons, photons and phonons on the same quantized footing, accessing new observables in strong light-matter coupling. Current approximations in the field almost exclusively focus on electronic excitations, neglecting electron-photon effects, for example, thereby limiting the applicability of conventional methods in the study of polaritonic systems, which requires understanding the coupled dynamics of electronic spins, nuclei, phonons and photons. With our approach we can access correlated electron-photon and photon-phonon dynamics2–7, essential to our latest work on driving quantum materials far out-of-equilibrium to control the coupled electronic and vibrational degrees-of-freedom 8–19. In the second part of my talk, I will demonstrate how the same approach can be generalized in the context of control of molecular quantum matter and quantum transduction. As a first example, I will discuss a cavity-mediated approach to break the inversion symmetry allowing for highly tunable even-order harmonic generation (e.g. second- and fourth-harmonic generation) naturally forbidden in such systems. This relies on a quantized treatment of the coupled light-matter system, similar to the driven case, where the molecular matter is confined within an electromagnetic environment and the incident (pump) field is treated as a quantized field in a coherent state. When the light-molecule system is strongly coupled, it leads to two important features: (i) a controllable strong-coupling-induced symmetry breaking, and (ii) a tunable and highly efficient nonlinear conversion efficiency of the harmonic generation processes 20–22. Both of these have implications for molecular quantum architectures. Being able to control molecules at a quantum level gives us access to degrees of freedom such as the vibrational or rotational degrees to the internal state structure. Finally, I will give an outlook on connecting ideas in cavity control of molecules with quantum information science.

Larval zebrafish can navigate their environment and seek conditions that meet their physiological needs. We refer to this process as homeostatic navigation. We use careful behavioral analysis, whole-brain imaging, and neuronal perturbations to identify the behavioral strategy and the neuronal circuitry that underlie this important behavior. In addition, I will recap recent studies from our lab, involving perceptual decision making and the identification of a heading direction network, that all together, provide insights into how the brain of this small vertebrate controls behavior across these various paradigms.

Proteins are the fundamental building blocks of life. They form high performance materials and carry out cellular functions. They are able to fulfil these roles by assembling together to form sophisticated structures and architectures, which in many cases extend to mesoscopic liquid or solid phases. This talk focuses on understanding the transitions between these phases, their fundamental material properties and the way that the modulate biological function and malfunction. I will then discuss two areas opened up by the control of protein assembly. I will first focus on the understanding of the mechanism of protein aggregation and the discovery of molecules that can ameliorate malfunctioning protein self-assembly in a range of age-associated disease states. I will then outline some of our efforts to control protein self-assembly to form silk-inspired sustainable materials

Statistical physics has a bad track record in describing large-N gravitational systems.
It has become clear over the last several years that there is a remarkable exception
to this rule. Resonant relaxation due to orbit-averaged secular dynamics in galactic nuclei
drives them to states of thermal and rotational equilibria on an astronomically short timescale.

There are fun applications: phase transitions leading to lopsided precessing equilibria (similar-looking to the nucleus of Andromeda), and strong clustering in eccentricity and inclination of stellar-mass black holes. Following Rauch and Tremaine, I will use statistical physics to argue that secular-dynamical "resonant friction" must exist and
that moreover, it likely plays a huge role in galactic nuclei. It controls the dynamics of Intermediate-Mass Black Holes as well
as that of stellar and accretion discs. The young stellar disc at the center of our Galaxy presents a good case study for this effect.