Accession Number : AD0714900

Title :   Cell Model of Quantum Liquids and Solids. I. Crystalline State.

Descriptive Note : Technical rept.,

Corporate Author : MASSACHUSETTS UNIV AMHERST DEPT OF PHYSICS AND ASTRONOMY

Personal Author(s) : Mullin,William J.

Report Date : 16 NOV 1970

Pagination or Media Count : 42

Abstract : A second quantized cell model Hamiltonian is derived to provide a model for quantum crystals and liquids. The Boson crystal is treated in this article. The cells are divided into two sublattices, regular which are usually occupied and interstitial which are usually empty. The particle hard cores are simulated by assuming Fermi commutation relations for operators referring to a single cell; this allows a discussion in terms of a spin analog Hamiltonian which is diagonalized in the spin wave approximation. Because the Hamiltonian includes a term which allows tunneling between regular and interstitial sites, the ground state includes a description of zero point motion and exchange via virtual intermediate interstitial occupation. Excited states include nonlocalized vacancies, interstitials and vacancy-interstitial pairs. Phonon states are not included in this analysis. The model exhibits a phase transition to the Bose condensed state which is examined briefly. (Author)

Descriptors :   (*SOLIDIFIED GASES, HELIUM), (*LIQUIFIED GASES, HELIUM), ANTIFERROMAGNETISM, SUPERFLUIDITY, PHASE STUDIES, GROUND STATE, EXCITATION, BOSONS

Subject Categories : Atomic and Molecular Physics and Spectroscopy
      Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE