Talks

Astrophysics and cosmology grew, symbiotically, alongside quantum mechanics, over the past hundred years. The developing fields of atomic, nuclear and particle physics found motivation and application to central problems in astrophysics. These included the elucidation of stellar and interstellar spectra, the powering of stars and supernovae, the origin of the chemical elements, the properties of neutron stars and the interpretation of cosmic rays.  This relationship continues and is expressed in some of the most pressing problems today, notably the nature and consequences of dark matter, the provenance of cosmic structure and baryon asymmetry, the properties of magnetars, the acceleration of the highest energy cosmic rays and the origin of life.

Achieving precise control over microbial community composition is critical for applications ranging from bioremediation to human health but remains challenging due to the complexity of microbial interactions and resource variability. This work presents a framework for the bottom-up engineering of microbial communities by leveraging resource dynamics and temporal niches in fluctuating environments.
This approach assembles and maintains microbial "dream teams" - small, defined communities with desired properties—using serial dilution experiments. By treating resource concentrations as dynamic "control knobs," it enables stable coexistence and precise tuning of species abundances. Theoretical models, informed by experimental data from natural and synthetic microcosms, incorporate ecological and metabolic parameters, including species-specific time lags and dilution factors, to identify resource combinations that maximize community stability and diversity.
I will also describe how to engineer a multi-cycle resource strategy to overcome resource limitations and dramatically increase microbial diversity. By systematically varying resource ratios across growth-dilution cycles, this strategy creates additional temporal niches that allow for the coexistence of a larger number of species than traditional methods. Numerical simulations demonstrate that multi-cycle strategies significantly enhance species diversity, approaching the theoretical upper bound of 2^n-1 species coexisting on n resources.

According to general relativity, the remnant of a binary black hole merger is a perturbed Kerr black hole. Perturbed Kerr black holes emit "ringdown" radiation which is well described by a superposition of damped exponentials ("quasinormal modes”), with frequencies and damping times that depend only on the mass and spin of the remnant. The observation of gravitational radiation emitted by black hole mergers might finally provide direct evidence of black holes, just like the 21 cm line identifies interstellar hydrogen. I will review the current status of this "black hole spectroscopy" program. I will focus on: (1) the role of nonlinearities in ringdown modeling, (2) the current observational status of black hole spectroscopy, and (3) future prospects for the observability of modified gravity effects and nonlinear modes.

The correspondence of AGT sets up, in part, a connection between six-dimensional superconformal theories and 2d CFT. We will give a mathematical construction of 2d CFT from 6d SCFT which involves recent progress in our understanding of the holomorphic twist 6d superconformal symmetry. We then turn to the question of enhancement of familiar structures in 2d CFT to 6d including the well-known Segal—Sugawara construction. Finally, I will set up a Dolbeault enhancement of the AGT correspondence which is expected to probe coherent cohomology of the moduli space of instantons.

Starting in the mid-1980s with the quantum control and detection of individual atoms/ions, we now have access to a variety of controllable quantum systems. One particular platform which has emerged as a popular choice is superconducting electrical circuits operating at ultra-low temperatures. These are micro to nanoscale electrical circuits that can be engineered to show quantum mechanical phenomena like superposition and entanglement. In this talk, I will introduce the concept of a quantum electrical circuit and how one can use superconducting materials to build them. The flexibility in circuit design allows one to create near ideal custom Hamiltonians which can be used to implement textbook measurements and explore various phenomena in previously unexplored regimes. The same flexibility also enables the possibility of large-scale chips for quantum computing applications. I will discuss some examples to illustrate the versatility of this platform and also highlight the various challenges in building a practical quantum computer.

On a microscopic scale, our world is governed by quantum physics. Beyond the fundamental questions and 'mysteries' of quantum mechanics, the ability to control this microscopic realm opens up exciting opportunities for new applications and quantum technologies—potentially more powerful than their classical counterparts. As we celebrate 2025 as the International Year of Quantum Science and Technology, marking 100 years since the formulation of quantum mechanics by Heisenberg and Schrödinger, we also commemorate three decades of progress in quantum information and quantum computing. This talk will provide an overview of quantum information from both conceptual and historical perspectives. We will explore the implementation and applications of quantum computers and simulators, quantum networks, and quantum metrology. Our primary focus will be on quantum optical systems, such as atoms and ions manipulated by laser light—prototypical examples of engineered quantum many-body systems. These systems can be controlled at the level of individual quanta, enabling precise manipulation, engineering, and distribution of quantum entanglement. Topics will include trapped ions as universal quantum processors, as well as digital and analog simulations of strongly correlated quantum matter using Rydberg atoms in tweezer arrays. We will highlight current research examples, such as quantum simulations of lattice gauge theories, the characterization and verification of quantum devices through Hamiltonian and Liouvillian learning, and the development of quantum algorithms for optimizing entanglement in quantum sensors.

This talk will go over the history, principles, development, and applications of inelastic light scattering, widely known as the Raman effect, concluding with some remarks on Raman and Mandelstam, the two major figures in the discovery.