A new application of the modal-Hamiltonian interpretation of quantum mechanics: The problem of optical isomerism

Abstract

In the context of the debates about the nature of molecularstructure, in this paper we have focused on Hund's paradox,derived from the difficulty in giving a quantum explanation foroptical isomerism. We have revised different attempts to solve theparadox, in particular, the widespread appeal to decoherence in recent literature; we have argued that none of these attempts iscompletely successful. On this basis, we have recalled the mainfeatures of the MHI in order to show how this interpretation offersa solution of Hund´s paradox in exclusively quantum terms.Since its first formulation in 2008, the MHI was developed inseveral articles, and was presented many times to varied audiences.It is interesting to notice the different reactions to the same proposal.Philosophers of physics usually insist on requiring thejustification for the selection of the Hamiltonian as the key todetermine the preferred context, by claiming that no basis of theHilbert space has a privileged status. By contrast, philosophers ofchemistry (and chemists) are always surprised by our insistence injustifying that selection, since in chemistry it is usual to work in thebasis of the energy. In fact, the MHI is in resonance with molecularchemistry, in the context of which molecules are almost alwaysdescribed in their stationary states, that is, in eigenstates of theHamiltonian, and a great deal of relevant knowledge is obtainedfrom studying the symmetries of the Hamiltonian. The MHI accountto optical isomerism fits in the framework of this resonance.