Using the techniques of quasi-Hermitian quantum mechanics and quantum field theory we use a similarity transformation to construct an equivalent Hermitian Hamiltonian for the Lee model. In the field theory confined to the V/Nθ sector it effectively decouples V , replacing the three-point interaction of the original Lee model by an additional mass term for the V particle and a four-point interac...

An isothermal truncation of the electromagnetic gyrofluid model of Snyder and Hammett Phys. Plasmas 8, 3199 2001 is shown to be Hamiltonian. The corresponding noncanonical Lie–Poisson bracket and its Casimir invariants are presented. The invariants are used to obtain a set of coupled Grad–Shafranov equations describing equilibria and propagating coherent structures. © 2009 American Institute of...

We propose and solve a Hamiltonian model for multidimensional epistastatic interactions between beneficial mutations. The model is able to give rise either to a phase transition between two equilibrium states, without any coexistence, or exhibits a state where hybrid species can coexist, with gradual passage from one wild type to another. The transition takes place as a function of the toleranc...