Monte Carlo simulations have become an established and useful method for treating
problems in classical statistical physics. Although the first attempts to apply these ideas to …

This colloquium reviews some unusual paramagnetic phenomena in granular high-
temperature superconductors. These are consistently explained by assuming that there is …

It is argued that the long-wavelength, low-temperature behavior of a two-dimensional
quantum Heisenberg antiferromagnet can be described by a quantum nonlinear σ model in …

In this Letter we describe a new technique for investigating phase transitions and dynamics
in interacting electron systems. This technique is based on the derivation and self-consistent …

We generalize a type of variational wave function introduced by Kasteleijn and Marshall, to
include long-range correlations and nonbipartite lattices. We find the lowest-energy wave …

A miniature superconducting resonator operating at 1.3 K and 900 MHz has been used to
measure the change in λ (T) from 1.3 K to T c in very high quality single crystals of YBa 2 Cu …

The effective Hamiltonian of strongly correlated electrons on a square lattice is replaced by a
renormalised Hamiltonian and the factors that renormalise the kinetic energy of holes and …

We discuss the solution of nontrivial conserving approximations for electronic correlation
functions in systems with strong collective fluctuations. The formal properties of conserving …

Unconventional superconductivity (SC) is said to occur when Cooper pair formation is
dominated by repulsive electron–electron interactions, so that the symmetry of the pair wave …

The CuO 2 planes in the high-temperature superconductors are described by a two-
dimensional Hubbard model. The model is investigated for an infinite system with one and …