PT Journal
AU Faleiro, R
   Pavao, R
   Costa, HAS
   Hiller, B
   Blin, AH
   Sampaio, M
TI Perturbative approach to entanglement generation in QFT using the S matrix
SO Journal of Physics A
JI J. Phys. A
PY 2020
BP 365301 - 19pp
VL 53
IS 36
DI 10.1088/1751-8121/aba214
LA English
DE S-matrix; entanglement; QFT; cross-section
AB We compute the variation of the von Neumann (VN) entropy Delta Sbetween the asymptoticinandoutmomenta modes of a real scalar field A, when elastically scattered against the modes of another scalar field B. This is done to see how the entanglement between the two fields' momenta changes under the scattering procedure. The calculation is separated into two case studies, one where the fields' asymptoticinstates are separable, and another where they are arbitrarily entangled. We perform a perturbative calculation to one loop order in the separable case, and verify that Delta Schanges in a non-trivial way when we vary the momentum of the incoming field modes and/or the coupling of the theory. Finally, also in the separable case, we show an explicit dependence between Delta Sand the cross-section of the collision, consistent with perturbation theory.
ER