[Seminar] Dr. Weslei Fontana "Dualities among quantum many body scars"

Speaker

Dr. Weslei / National Tsing Hua University

Title

Dualities among quantum many body scars

Abstract

Dualities have long been a powerful way to understand quantum many-body systems, especially when perturbative methods fail. Recently, they have even been reinterpreted as generalized symmetries, which can strongly constrain the low-energy description and guarantee that the ground state is non-trivial. In this talk, I’ll discuss how duality can also play a role in non-equilibrium setups, focusing on quantum many-body scars (QMBS) — special eigenstates of chaotic Hamiltonians that refuse to thermalize. The duality gives us two things: first, a way to generate new examples of QMBS, and second, it give us insight on their robustness -- some QMBS states are more robust than others due to a stronger non-thermal behavior, measured by their matrix elements distribution. To make these ideas concrete, I’ll walk through a simple 1+1D spin chain related by Kramers–Wannier duality, and show that while QMBS may show up at first, their behavior can change completely once we introduce a dual perturbation.

Profile of Speaker

Dr. Weslei Fontana began his academic career at the Universidade Estadual de Londrina in Brazil, where he first explored the thermodynamic properties of black holes during his master’s studies. During his PhD, he made a significant shift toward condensed matter physics, applying his background in high-energy theory to develop methods for deriving effective quantum field theory descriptions of fractional quantum Hall systems.

While pursuing his PhD, he spent a period as a visiting scholar at Boston University, collaborating with Prof. Claudio Chamon on projects involving fracton physics, UV-IR mixing, and generalized symmetries. Together, they developed a general framework to identify the Chern–Simons–like topological field theories that capture the universal features of certain fracton models. This approach provided a more transparent understanding of these systems, simplifying analyses that would not be so obvious from direct lattice computations.

After returning to Brazil to complete his PhD, Dr. Fontana joined the International Institute of Physics (IIP) in Natal, Brazil, as a postdoctoral researcher in the Quantum Matter and Quantum Information group led by Prof. Rodrigo Pereira. His research there spanned several directions, including fracton physics (both theoretical and Rydberg implementations), stabilizer codes, parton constructions, and chiral spin liquids.

He is currently a postdoctoral researcher at National Tsing Hua University (NTHU) in Taiwan, in the group of Prof. Yi-Ping Huang. His current work leverages his experience in strongly correlated and topological systems to investigate non-equilibrium dynamics, with a particular focus on quantum many-body scars.

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Meeting ID: 989 7620 7708
Passcode: 435188