Talks

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.

Ordered phases of matter have close connections to computation. Two prominent examples are spin glass order, with wide-ranging applications in machine learning and optimization, and topological order, closely related to quantum error correction. Here, we introduce the concept of topological quantum spin glass (TQSG) order which marries these two notions, exhibiting both the complex energy landscapes of spin glasses, and the quantum memory and long-range entanglement characteristic of topologically ordered systems. Our work introduces a topological analog of spin glasses that preserves quantum information and displays robust many-body entanglement even at finite temperatures, opening new avenues for both statistical mechanics and quantum computer science.

Microbial communities assemble and thrive in strongly fluctuating boom-and-bust environments by adopting distinct metabolic strategies to consume resources. While much attention has been given to understanding these strategies in isolated species, their ecological implications in complex communities remain poorly understood. Here, we combine theoretical and computational frameworks to investigate the assembly and ecological properties of microbial communities with diauxic (sequential) and co-utilization strategies.
We show that diauxic microbial communities, where species sequentially utilize resources, spontaneously develop complementary resource preferences during assembly. This complementarity arises because sequential utilization disproportionately relies on the top-choice resource for growth, leading to intuitive ecological partitioning. A geometric approach to analyzing these serially diluted communities further explains emergent patterns, such as the absence of species preferring suboptimal resources for growth.
Comparing sequential and co-utilization strategies, we find that sequential utilizers dominate in species-rich, high-competition communities, leveraging their resilience to fluctuating resource ratios. Their ecological advantage lies in growth rate distributions characterized by wider upper tails, despite lower averages, enabling efficient niche packing and structural stability. Conversely, co-utilizers thrive in low-diversity communities, benefiting from consistently higher average growth rates.
Our work provides a unified explanation for the coexistence of sequential and co-utilizing strategies in natural ecosystems and predicts patterns of community assembly shaped by metabolic strategies. These findings offer testable hypotheses for understanding the dynamics of microbial communities in natural and synthetic environments.