Dynamics of Critical Dirac Spin Liquids

Quantum fluctuations can inhibit long-range ordering in frustrated magnets and potentially lead to quantum spin liquid (QSL) phases. A prime example is the gapless Dirac quantum spin liquid (DSL) with an emergent U(1) gauge field, which can be described at low energies in terms of quantum electrodynamics in 2+1 dimension (QED₃). Despite the availability of several promising triangular lattice candidate materials and recent advances in numerical methods the description of their dynamical response is an outstanding challenge. In this talk I will discuss our recent theory for the dynamical spin structure factor of the triangular lattice J₁-J₂ model. We not only find good agreement between recent experiments and rigorous numerics but argue that our self-consistent parton mean field theory , which includes fluctuations leading to spinon bound states, is a powerful tool for understanding the response of other types of QSLs and their instabilities.