Sanchidrian-Vaca, CarlosLuis Aina, Alfredo2023-06-172023-06-172018-04-092469-992610.1103/PhysRevA.97.043810https://hdl.handle.net/20.500.14352/12084©2018 American Physical Society. A.L. acknowledges financial support from Spanish Ministerio de Economía y Competitividad Project No. FIS2016-75199-P, and from the Comunidad Autónoma de Madrid research consortium QUITEMAD+ Grant No. S2013/ICE-2801.We examine entanglement between number and polarization, or number and relative phase, in pair coherent states and two-mode squeezed vacuum via linear entropy and covariance criteria. We consider the embedding of the two-mode Hilbert space in a larger space to get a well-defined factorization of the number-phase variables. This can be regarded as a kind of protoentanglement that can be extracted and converted into real particle entanglement via feasible experimental procedures. In particular this reveals interesting entanglement properties of pairs of coherent states.engjournal articlehttp://dx.doi.org/10.1103/PhysRevA.97.043810https://journals.aps.orgopen access535Tensor product structuresPhase-differenceQuantum opticsDecoherenceVariablesCavityFieldsGeofísicaÓptica (Física)2507 Geofísica2209.19 Óptica Física