A double Tavis-Cummings model (DTCM) is developed to simulate the
entanglement dynamics of realistic quantum information processing where two
entangled atom-pairs AB and CD are distributed in such a way that atoms
AC are embedded in a cavity a while BD are located in another remote
cavity b. The evolutions of different types of initially shared entanglement
of atoms are studied under various initial states of cavity fields. The results
obtained in the DTCM are compared with that obtained in the double
Jaynes-Cummings model (DJCM) [J. Phys. B \textbf{40}, S45 (2007)] and an
interaction strength theory is proposed to explain the parameter domain in
which the so-called entanglement sudden death occurs for both the DTCM and
DJCM.Comment: 11 figure