# Minimal energy cost of entanglement extraction. (arXiv:1904.06246v1 [quant-ph])

We compute the minimal energy cost for extracting entanglement from the
ground state of a bosonic or fermionic quadratic system. Specifically, we find
the minimal energy increase in the system resulting from replacing an entangled
pair of modes, sharing entanglement entropy $\Delta S$, by a product state, and
we show how to construct modes achieving this minimal energy cost. Thus, we
obtain a protocol independent lower bound on the extraction of pure state
entanglement from quadratic systems. Due to their generality, our results apply
to a large range of physical systems, as we discuss with examples.