  Recently a new class of single-photon timed-Dicke (TD) subradiant states has
been introduced with possible applications in single-photon based quantum
information storage and on demand ultrafast retrieval [Scully M. O., Phys. Rev.
Lett., 115 (2015) 243602]. However, the influence of any kind of virtual
processes on the decay of these new kind of subradiant states has been left as
an open question. In the present paper, we focus on this problem in detail. In
particular, we investigate how pure Fano-Agarwal couplings and other virtual
processes arising from non-rotating wave approximation impact the decay of
otherwise sub and superradiant states. In addition to the overall virtual
couplings among all TD states, we also focus on the dominant role played by the
couplings between specific TD states.
