Abstract: Fracton phases represent an exotic form of quantum order characterized by restricted-mobility excitations and UV/IR mixing. Studying their boundaries may provide an unusually direct probe of the underlying bulk order. However, continuum theories permit stable gapless boundary phases, whereas exactly solvable lattice models naturally produce only gapped ones. In this talk, I will focus on this mismatch between continuum and lattice descriptions and discuss a possible way to reconcile them using the boundary theory of the Chamon model. In particular, by rewriting the lattice model in a representation where the original and dual spin variables appear simultaneously, we can systematically derive the corresponding field theory and recover previous continuum predictions. This construction also suggests how to engineer microscopic interactions that may realize other exotic gapless fracton phases.

Speaker Bio: Dr. Weslei Fontana is a postdoctoral researcher in the Theory of Quantum Matter Unit at OIST, working on strongly correlated and topological quantum systems. He received his PhD in Brazil, where he developed field-theoretic approaches to fractional quantum Hall systems, and was a visiting scholar at Boston University working with Prof. Claudio Chamon on fracton physics. He subsequently held postdoctoral positions at the International Institute of Physics in Brazil and National Tsing Hua University in Taiwan. He joined OIST in July 2026.