It is shown that the potential-energy surface in K2ZnCl4 contains a double-well structure, very similar to some of the other A2BX4 compounds (e.g., K2SeO4, Rb2ZnCl4), except that the double well is much deeper and broader, giving rise to a highly disordered high-temperature phase as observed experimentally. A lattice-dynamics study of the Pna21 structure shows an instability with the wave vecto...

We show that melting the quark mass, the scalar σ mass and the quark condensate leads uniquely to the quark-level SU(2) linear σ model field theory. Upon thermalization, the chiral phase transition curve requires Tc = 2f CL π ≈ 180 MeV when μ = 0, while the critical chemical potential is μc = mq ≈ 325 MeV . Transition to the superconductive phase occurs at T (SC) c = ∆/πe−γE . Coloured diquarks...

A quantum phase transition (QPT) is a zero-temperature, generically continuous transition tuned by a parameter in the Hamiltonian at which quantum fluctuations of diverging size and duration (and vanishing energy) take the system between two distinct ground states [4]. This short review discusses the characteristic aspects of QPT and illustrates possible applications in physics and biology.