Realistic protocol to measure entanglement at finite temperatures

Abstract

It is desirable to relate entanglement of many-body systems to measurable observables. In systems with a conserved charge, it was recently shown that the number entanglement entropy (NEE) - i.e. the entropy change due to an unselective subsystem charge measurement - is an entanglement monotone. Here we derive finite-temperature equilibrium relations between Renyi moments of the NEE, and multi-point charge correlations. These relations are exemplified in quantum dot systems where the desired charge correlations can be measured via a nearby quantum point contact. In quantum dots recently realizing the multi-channel Kondo effect we show that the NEE has a nontrivial universal temperature dependence which is now accessible using the proposed methods.