Entanglement of disjoint intervals in CFT: entropies and negativity Seminar

Entanglement of quantum states and its measures play an important role in many areas of theoretical physics. The entanglement entropy is a good measure for pure states, while the negativity allows to measure entanglement for mixed states.

We first discuss the computation of the Renyi entropies for a generic number of disjoint intervals in CFT, providing analytic results for the free compactified boson and the Ising model. The analysis involves a special class of higher genus Riemann surfaces. This allows us to describe a method to compute negativity in QFT through the replica trick, giving formulas for the case of two adjacent intervals and two disjoint ones. The analytic results have been checked using various methods like exact diagonalization for the harmonic chains and tensor networks techniques for the Ising model.