News

Our work on electronic bound states in the continuum in Pd₅AlI₂ is now published in Science. Destructive quantum interference traps electron waves around atomic defects—even inside a metal.

Ellen Neff’s Columbia Quantum Initiative feature, “Quantum Interference Is Key to Catching Electron Waves,” tells the story behind our Science paper on electronic bound states in the continuum in Pd₅AlI₂. Read the feature for the experiments, the quantum-interference mechanism, and the people behind the work.

Peter’s new preprint with Raquel, Vacancy-driven topological transition of a Chern insulator, is on arXiv. Ring states bound to individual vacancies overlap and hybridize into an impurity band, providing a microscopic picture of how strong disorder destroys a Chern phase. Figure 1 illustrates the ring-state percolation picture.

Our new preprint with Gabrielle Carrel, Nishchhal Verma, Fatmagül Katmer, and Leslie M. Schoop connects chemical bonding to the quantum geometry of electronic bands. It identifies noncollinear three-center bonds as a source of Berry curvature and relates bond fluctuations to electromagnetic response. Read The quantum geometry of the chemical bond on arXiv.

Our work with Roni Ilan, Zhida Song, Andrei Bernevig, and Ady Stern is now published in Newton, article 100699 (2026). Ring states in topological materials explores impurity-bound states as a real-space probe of band topology.

The Air Force Office of Scientific Research has awarded funding for “Theoretical Framework for Locally Probing Quantum Geometry and Entanglement in Quantum Materials.” The project will connect electronic wavefunctions to local measurements of geometry, topology, and entanglement.

Harshitra, Nish, and Dani develop Cell Natural Orbitals into a systematic local basis for quantum-material bands. Applied to twisted bilayer WSe₂, the construction identifies the orbitals needed to reproduce symmetry, charge density, and quantum geometry across twist angle.

Nish, Harshitra, and Dani introduce Cell Natural Orbitals, a local basis that organizes interactions in topological bands through the geometry of their wavefunctions. The construction exposes a hierarchy of interaction channels and connects band topology to real-space correlations.

Nish’s manuscript develops a geometric description of metallic response across long and short times and is now on arXiv.

The NSF has renewed Columbia’s Materials Research Science and Engineering Center for six years. Our group is part of IRG2 on nonequilibrium quantum metamaterials, developing theory for driven topological phases and quantum geometry in materials coupled to cavities.

The Army Research Office has funded our project, “Quantum Geometry as a Knob of Collective Phenomena in 2D Superlattices.” The project will develop moiré models that retain spatial orbital embedding and use them to predict geometric signatures in collective modes and superconductivity.

Julian’s manuscript connects symmetry-enforced wavefunction zeros to real-space measurements of band topology and is now on arXiv.