The magnetic interaction of a pair of bound magnetic polarons (BMP) in diluted magnetic semiconductors (DMS) is analyzed via a generalized Hubbardtype Hamiltonian for two carriers in the presence of effective magnetic fields arising from the magnetic polarization of their respective polarons. For the case where the magnetic fields at the two sites have equal magnitude but are allowed to have ar...

We suggest that, similar to the many applications of chiral effective Lagrangian made recently to semileptonic decays of heavy hadrons involving Goldstone bosons, chiral symmetry can also be applied to many-body nonleptonic decays of heavy hadrons. As examples we establish the chiral effective Hamiltonian for some typical many-body nonleptonic decays of bottom hadrons. We discuss the lowest-ord...

We study a similarity transformation to construct an effective Hamiltonian systematically, which does not contain particle-numberchanging interactions. We found it very advantageous that the effective Hamiltonian can be obtained from Feynman diagrams, so that we can use the covariant perturbative renormalization procedure. We apply this to the Light-Front Yukawa model as an example and confirm ...

By integrating out the degrees of freedom of the small spheres in a binary mixture of large and small hard spheres, we derive an explicit effective Hamiltonian for the large spheres. Using the two-body (depletion potential) contribution to this effective Hamiltonian in simulations, we find stable fluid-solid and both metastable fluid-fluid and solid-solid coexistence in a mixture with size rati...

In a recent work the resonance widths in a microwave billiard with attached waveguide were studied in dependence on the coupling strength [E. Persson et al., Phys. Rev. Lett. 85, 2478 (2000)], and resonance trapping was experimentally found. In the present paper an effective Hamiltonian is derived that depends exclusively on billiard and waveguide geometry. Its eigenvalues give the poles of the...

It has two parameters α, m. From a physical point of view the equation is a QCD-inspired effective one-body bound-state equation for modeling mesons with different constituent quark flavors [1]. M are the invariant mass squares of the physical mesons, while m = m1 = m2 is the effective mass of the quark and anti-quark. It takes this explicit form due to an over-simplification by the ↑↓-model [1...

For the Fermi-Pasta-Ulam chain, an effective Hamiltonian is constructed, describing the motion of approximate, weakly localized discrete breathers traveling along the chain. The velocity of these moving and localized vibrations can be estimated analytically as the group velocity of the corresponding wave packet. The Peierls-Nabarro barrier is estimated for strongly localized discrete breathers.

We use a Gaussian wave functional for the ground state to reorder the Hamiltonian into a free part with a variationally determined mass and the rest. Once spontaneous symmetry breaking is taken into account, the residual Hamiltonian can, in principle, be treated perturbatively. In this scheme we analyze the O(1) and O(2) scalar models. For the O(2)–theory we first explicitly calculate the massl...

We construct the effective Hamiltonian which governs the renormalization group flow of the gluon distribution with increasing energy and in the leading logarithmic approximation. This Hamiltonian defines a two–dimensional field theory which involves two types of Wilson lines: longitudinal Wilson lines which describe gluon recombination (or merging) and temporal Wilson lines which account for gl...

We derive an effective Hamiltonian for Ga(1-x)Mn(x)As in the dilute limit, where Ga(1-x)Mn(x)As can be described in terms of spin F=3/2 polarons hopping between the Mn sites and coupled to the local Mn spins. We determine the parameters of our model from microscopic calculations. Our approach treats the large Coulomb interaction in a nonperturbative way, captures the effects of spin-orbit coupl...