A soluble seven-vertex model for clusters with interfacial bending energy
A model describing an ensemble of disjoint clusters on a square lattice is introduced. In addition to the usual surface energy terms, in x and in y, the model includes a bending energy in c per corner in the interface. It is formulated as a seven-vertex model which is in general not solvable. For beta in c=ln(2)/2, however, this seven-vertex model becomes free fermionic one and an exact expression for its free energy is derived. In the extreme anisotropic ('Hamiltonian') limit the operator content coincides with that of the 1D Ising model in a transverse field. Three critical lines with Ising-like behaviour are found.

title: Flux-carrying fermions and the second virial coefficient.
abstract: The second virial coefficient {ital B}{sub 2} for a system of spin-one-half flux-carrying fermions is computed. It is found that there arise significant differences from known results for the corresponding spinless system. Apart from the existence of cusps and a restricted periodicity of {ital B}{sub 2} when viewed as a function of the flux parameter {alpha}, one obtains here the remarkable result that there exist discontinuities in {ital B}{sub 2} at all even, nonzero values of {alpha}.

title: GRASSMANNIAN APPROACH TO THE RESONATING-VALENCE-BOND STATE OF THE 2D HEISENBERG ANTIFERROMAGNET
abstract: A systematic representation of the resonating-valence-bond state of the 2D spin-1/2 Heisenberg antiferromagnet in terms of anticommuting Grassmann variables is derived. This representation is extended to the dilute case and the holon statistics are considered. Independent phase fluctuations on each valence-bond yield a U(1) gauge theory with low-lying gapless excitations in accordance with other approaches.

title: The nearest-neighbor resonating-valence bond state in a Grassmannian form
abstract: The nearest-neighbor resonating-valence bond (NNRVB) state is studied using classical anticommuting (Grassmann) variables. The classical partition function corresponding to the self-overlap of the NNRVB wavefunction is generated from a local (bond) Hamiltonian expressed in terms of four anticommuting variables. It is shown that the one-particle-per-site constraint introduces an interaction term which is a local product of all four variables. Two approaches are applied to study this Hamiltonian: (i) a self-consistent field decoupling scheme and (ii) a systematic perturbation expansion around the unconstrained soluble point. Bounds on the norm of the wavefunction are derived. Extensions to the presence of holes, long-range valence bonds, and the introduction of phase fluctuations [which violate the Marshall sign rule and yield aU(1) gauge theory] are discussed.

title: Initial nucleon structure results with chiral quarks at the physical point
abstract: S. Syritsyn∗ a, T. Blum a,b, M. Engelhardt c, J. Green d , T. Izubuchi a, C. Jung a, S. Krieg e, M. Lin f , S. Meinel a,g, J. Negele h, S. Ohta i, j,a, A. Pochinsky h, E. Shintani a,k (RBC and LHP collaborations) a RIKEN/BNL Research Center, Brookhaven National Laboratory, Upton, NY, 11973, USA b Physics Department, University of Connecticut, Storrs, CT 06269, USA c Department of Physics, New Mexico State University, Las Cruces, NM 88003, USA d Institut fur Kernphysik, Johannes Gutenberg-Universitat Mainz, D-55099 Mainz, Germany e Bergische Universitat Wuppertal, D-42119 Wuppertal, Germany and IAS, Julich Supercomputing Centre, Forschungszentrum Julich, D-52425 Julich, Germany f Computational Science Center, Brookhaven National Laboratory, Upton, NY 11973, USA g Department of Physics, University of Arizona, Tucson, AZ 85721, USA h Massachusetts Institute of Technology, Cambridge, MA 02139, USA i Institute of Particle and Nuclear Studies, KEK, Tsukuba, Ibaraki 3050801, Japan j Department of Particle and Nuclear Physics, SOKENDAI, Hayama, Kanagawa, 2400193, Japan k PRISMA Cluster of Excellence, Institut fur Kernphysik and Helmholtz Institute Mainz, Johannes Gutenberg-Universitat Mainz, D-55099 Mainz, Germany E-mail: ssyritsyn@quark.phy.bnl.gov