Topological Phase Transitions in Strongly Interacting Fermi Systems (J W Clark) Semifluxon Dynamics in Extended Josephson Junctions (H Farhan) On the Quantum Hall Effect in Graphene (S Fujita) Ergodicity and Chaos in a System of Harmonic Oscillators (M H Lee) Fluid Helium-4 in Thermal Equilibrium (M Ristig) On the Generalised Slater Approximation (E Suraud) An Informative Method for the Diagnostics of Superconductors (K Rostami) Numerical Study of Pi-Junction Using Spin Filtering Barriers (S Kawabata) RPA Approach to Nonlinear Transport in Quantum Dots (B Tanatar) and other papers.

Condensed Matter Theories

Variational theory of nuclear matter

The current state of nuclear matter calculations is described with special reference to the present disagreement between the variational and Brueckner--Bethe methods. The system is assumed to consist of point nucleons with a nonrelativistic Hamiltonian containing the kinetic energy and two-body potentials. The physical ideas of the variational method, especially of its hypernetted-chain version, and of the Brueckner: Bethe method are outlined. Practical ways of testing the validity of these mehtods are discussed and are illustrated by numerical results taken from the literature. It is found for central forces that the hypernetted-chain variational method, if properly used, gives reliable upper bounds to the ground-state energy. Lowest-order Brueckner--Bethe results lie well above these upper bounds, and it is both important and feasible to check whether higher-order corrections will bring the Brueckner--Bethe results into agreement with the variational ones. For realistic nuclear potentials, which have tensor forces, spin--orbit forces, etc., the situation is much less clear. An adequate calculation has not yet been done by either the variational or Brueckner--Bethe method. For the Reid potential, with the presently available numerical results, the variational calculation predicts a much higher saturation density than the Brueckner--Bethe calculation. Feasible calculations that will help to resolve thismore » discrepancy are discussed.« less

Current state of nuclear matter calculations

An iterative procedure is presented to exactly calculate the two-body distribution function of an infinite fermion system described by a Jastrow wave function of general product form. In the approximation of neglecting the elementary diagrams the procedure leads to integral equations which are the analogues of the well-known hypernetted-chain equation for the boson case. Preliminary numerical calculations have been performed for the ground state of nuclear matter using central, hard-core
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potentials; the results obtained seem to indicate the necessity of using the fermion HNC approximation even at nuclear densities.

D.A. Chakkalakal

Papers

Numerical comparison of reaction-matrix and Jastrow methods for nuclear matter

Numerical comparison of reaction-matrix and Jastrow methods for nuclear matter: A reassessment