In this paper we propose a "second quantization" scheme especially suitable
for dealing with nontrivial, highly symmetric phase spaces, implemented wi
thin a more general group approach to quantization, which recovers the stan
dard quantum field theory (QFT) for ordinary relativistic linear fields. We
emphasize, among its main virtues, greater suitability in characterizing v
acuum states in a QFT on a highly symmetric curved space-time and the absen
ce of the usual requirement of global hyperbolicity. This can be achieved i
n the special case of the Anti-de Sitter universe, on which we explicitly c
onstruct a QFT.