Operationally accessible entanglement in bipartite systems of indistinguishable particles could be reduced due to restrictions on the allowed local operations as a result of particle number conservation. In order to quantify such effects, Wiseman and Vaccaro [Phys. Rev. Lett. 91, 097902 (2003)] introduced an operational measure of the accessible von Neumann entanglement entropy. Motivated by advances in measuring Rényi entropies in quantum many-body systems subject to conservation laws, we introduce a generalization of the accessible entanglement that is computationally and experimentally accessible. Using the Widom theorem, we investigate its scaling with the size of a spatial subregion for free fermions and find a logarithmically violated area law scaling, similar to the spatial entanglement entropy, with at most, a double-log leading-order correction. A modification of the correlation matrix method confirms our findings in systems of up to 10^5 particles.
This repository includes code, scripts and data to generate the figures in H. Barghathi, C. M. Herdman and A. Del Maestro (arXiv:1804.01114). which was published in 2018 as Phys. Rev. Lett., 121, 150501 (2018).
The creation of these materials was supported in part by the National Science Foundation under Award No. DMR-1553991.
