The Role of Geometry and Topology in Quantum Light-matter

 

Theory projects in the Srivastava lab seek to relate non-trivial Bloch band geometry to observable responses of solid state systems, particularly transition metal dichalcogenides and Dirac materials such as Weyl semimetals.  A non-trivial geometry of electronic bands in a solid can result in effective electromagnetic fields in the reciprocal space. Can we use light to tune such fields? Is it possible to induce non-trivial geometry and topological states of light/matter using light-matter interactions? Our research hopes to address these questions.

Current projects explore the role Berry curvature and the quantum Fubini-Study metric beyond the single-particle paradigm, in interacting systems such as excitons and other low energy excitations [1].  We are also investigating the role of the quantum metric and Berry curvature in the dynamics of localized Bloch electrons via the semiclassical wave packet formulation of electron dynamics.

TF.png

Berry curvature and QGT modify exciton spectrum [1]

 

1. “Signatures of Bloch-band geometry on excitons: Nonhydrogenic spectra in transition-metal dichalcogenides,” A. Srivastava and A. Imamoglu, Phys. Rev. Lett. 115, 166802 (2015).