Entanglement measures of a new type pseudo-pure state in accelerated frames

In this work we analyze the characteristics of quantum entanglement of the Dirac field in noninertial reference frames in the context of a new type pseudo-pure state, which is composed of the Bell states. This will help us to understand the relationship between the relativity and quantum information theory. Some states will be changed from entangled states into separable ones around the critical value F = 1/4, but there is no such a critical value for the variable y related to acceleration a. We find that the negativity NABI(ρABITA) increases with F but decreases with the variable y, while the variation of the negativity NBIBII(ρBIBIITBI) is opposite to that of the negativity NABI(ρABITA). We also study the von Neumann entropies S(ρAB_I) and S(ρB_IB_II). We find that the S(ρAB_I) increases with variable y but S(ρBIBII) is independent of it. However, both S(ρAB_I) and S(ρB_IB_II) first decreases with F and then increases with it. The concurrences C(ρAB_I) and C(ρB_IB_II) are also discussed. We find that the former decreases with y while the latter increases with y but both of them first increase with F and then decrease with it.