Quantum electrodynamic phases in triangular magnetic systems
Christina Zhou (email@example.com)
*All are welcome to this event!
Quantum electrodynamics in (2+1) D (QED_3) consists of relativistic Dirac fermions strongly interacting with photons. Quantum magnets and electron systems under magnetic fields, meanwhile, represent 2 correlated paradigms in magnetism. We show that from symmetry reasoning, QED_3 emerges as a robust, critical phase both in triangular spin-1/2 magnets (called Dirac spin liquid), and half-filled Chern bands of electrons under periodic magnetic fields.
First triangular lattice Dirac spin liquid is shown to be stable as relevant monopole events are forbidden by symmetries. Furthermore, it is proximate to a plethora of symmetry breaking phases, furnishing a unifying framework for 2d frustrated magnets. Numerical and experimental signatures are discussed.
Next, I will show that QED_3 with 3 Dirac fermion species arises in a simple setup of Dirac materials under periodic magnetic fields with triangular lattice structure. Tuning chemical potential that breaks particle-hole symmetry will drive a transition among exotic incompressible states called fractional Chern insulators. Physical observables, numerical and potential experimental prospects are discussed.
Xue-Yang Song obtained her PhD in theoretical condensed matter in 2021 and is currently a Moore postdoctoral fellow at MIT. She studies strongly correlated matter that shows emergent quantum phenomena like fractional excitations and high-temperature superconductivity. She is interested in both developing formal theories and making concrete connections to realistic solid state or synthetic systems. Besides physics, she enjoys cycling and playing with her cat.