Speaker
Description
Recently, there has been intense research activity on the interplay between symmetries and entanglement, exploiting the block-diagonal structure of the reduced density matrix (RDM) in each charge sector. The goal of this talk is to study how the presence of a global U(1) charge affects the modular operator, a central object in the algebraic description of quantum field theory (QFT). Roughly speaking, the modular operator generalizes the RDM and remains well-defined even in cut-off-free QFTs. I will discuss the symmetry resolution of the modular operator and of the modular correlation functions of U(1)-invariant operators. This will be achieved by decomposing the entire algebra of observables into subalgebras corresponding to distinct charge sectors. Interestingly, in the explicit example of the 1+1-dimensional free massless Dirac QFT, the symmetry-resolved modular correlation functions are independent of the charge sector. Based on ArXiv:2305.02343 and ArXiv:2510.02441.