Decoherence of Morse oscillator in the presence of dissipationless environment

The much-studied Morse oscillator (MO) is couched here in the context of an open quantum system, in which the interaction with the quantum environment, however, is taken to commute with the subsystem Hamiltonian. The result is decoherence sans dissipation because of dephasing in the off-diagonal elements of the reduced density operator. The analytical results are numerically computed for a range of parameters for different attributes of decoherence. Finally, a comparison is made for the corresponding harmonic system in order to highlight the significance of anharmonicity in the MO as far as dependencies on the temperature and the environmental coupling are concerned.