Decoherence of entangled kaons and its connection to entanglement measures

We study the time evolution of the entangled kaon system by considering the Liouville–von Neumann equation with an additional term which allows for decoherence. We choose, as generators of decoherence, the projectors to the two-particle eigenstates of the Hamiltonian. Then we compare this model with the data of the CPLEAR experiment and find in this way an upper bound on strength λ of the decoherence. We also relate λ to an effective decoherence parameter ζ considered previously in literature. Finally we discuss our model in the light of different measures of entanglement, i.e., von Neumann entropy S, entanglement of formation E, and concurrence C, and we relate decoherence parameter ζ to the loss of entanglement: 1-E. © 2003 The American Physical Society.