“…The properties of this exactly solvable model have been analysed in great detail, see e.g. [57,64,56,68,18,62,11,32,58,9,10]. Independently, the quantum spherical model was also obtained via the so-called 'hamiltonian limit' [50] as the logarithm of the transfer matrix in an extremely anisotropic limit [65,35,38].…”