Conditions for separability in multiqubit systems with an accelerating qubit using a conditional entropy

We study the separability in multiqubit pure and mixed Greenberger-Horne-Zeilinger (GHZ) and W states with an accelerating qubit using the Abe-Rajagopal (AR) q-conditional entropy. We observe that the pure multiqubit GHZ and W states in the inertial-noninertial bipartition with one of their qubits accelerated will remain nonseparable irrespective of the qubit's acceleration. In these systems, we capture the variation of their nonseparability with respect to the acceleration of the qubit and the AR q-conditional entropy parameter q. However, in the corresponding multiqubit mixed states obtained by introducing a global noise to the above pure states, we could get stronger conditions on their separability in the inertial-noninertial bipartition, in terms of the acceleration of the qubit, the noise parameter, and the number of qubits in the system, in the asymptotic limit of the parameter q. These conditions obtained from the AR q-conditional entropy serve as necessary conditions for separability in such multiqubit states with a relativistic qubit.