  Experimental data and the principles of quantum mechanics suggest that a
crystal is a condensate of `wavicles' enclosed in a box, where `wavicle'
denotes the indefinite wave-particle status of the microscopic constituents.
When it is not perturbed the crystal is in a classical-like state. The
wavefunction, the internal energy and the entropy are all of them equal to
zero. The thermodynamic temperature is indefinite. Perturbations via energy-
and/or momentum-transfer reveal quantum effects. The temperature laws for the
heat capacities of some hydrogen-bonded crystals are rationalized with
superposition states depending on the quantum temperature which is
crystal-dependent. Heat-transfer is a coherent anentropic process. Apart from
energy conservation, the other laws of thermodynamics are irrelevant.
