  In this paper we study exceptional-point (EP) effects and quantum sensing in
a parity-time (PT)-symmetric two-qubit system with the Ising-type interaction.
We explore EP properties of the system by analyzing degeneracy of energy
eigenvalues or entanglement of eigenstates. We investigate entanglement
dynamics of the two qubits in detail. In particular, we demonstrate that the
system can create the steady-state entanglement in the PT-broken phase and
collapse-revival phenomenon of entanglement in the PT-symmetric phase during
the long-time evolution. We show that entanglement can be generated more
quickly than the corresponding Hermitian system. Finally, we prove that the
sensitivity of eigenstate quantum sensing for the parameters exhibits the
remarkable enharncement at EPs, and propose a quantum-coherence measurement to
witness the existence of EPs.
