The Quantum State of Classical Matter I: Solids and Measurements

Abstract

Using the kinematic constraints of classical bodies we construct the allowable wavefunctions corresponding to classical solids. These are shown to be long lived metastable states that are qualitatively far from eigenstates of the true Hamiltonian. Extensions of this give an explicit description of phonon oscillations in terms of the wavefunction itself and some consequences for the general validity of the quasiparticle picture are presented. An intrinsic theory of quantum measurement naturally arises based on Schr\"{o}dinger evolution that is local, consistent with relativity and extends to the case of noninertial and deformable measurement devices that can have time changing internal properties. This theory agrees with the Born interpretation in the limit of static measuring devices. Care is given to the transport of conserved quantities during measurement.