Cascade of quantum transitions and magnetocaloric anomalies in an open nanowire

A sequence of magnetocaloric anomalies occurring with the change in a magnetic field $H$ is predicted for an open nanowire with the Rashba spin-orbit coupling and the induced superconducting pairing potential. The nature of such anomalies is due to the cascade of quantum transitions related to the successive changes in the fermion parity of the nanowire ground state with the growth of the magnetic field. It is shown that the critical $H_c$ values fall within the parameter range corresponding to the nontrivial values of the $Z_2$ topological invariant of the corresponding 1D band Hamiltonian characteristic of the $D$ symmetry class. It is demonstrated that such features in the behavior of the open nanowire are retained even in the presence of Coulomb interactions.