title: Entanglement and composite bosons.
abstract: We build upon work by C. K. Law [Phys. Rev. A 71, 034306 (2005)10.1103/PhysRevA.71.034306] to show in general that the entanglement between two fermions largely determines the extent to which the pair behaves like an elementary boson. Specifically, we derive upper and lower bounds on a quantity chi{N+1}/chi{N} that governs the bosonic character of a pair of fermions when N such pairs approximately share the same wave function. Our bounds depend on the purity of the single-particle density matrix, an indicator of entanglement, and demonstrate that if the entanglement is sufficiently strong, the quantity chi{N+1}/chi{N} approaches its ideal bosonic value.
authors.affiliation: Department of Physics, Williams College, Williamstown, Massachusetts 01267, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Chudzicki
authors.forename: Olufolajimi
authors.initials: O
authors.lastname: Oke
authors.forename: William K
authors.initials: WK
authors.lastname: Wootters