The concept of confinement states that in certain systems the constituent particles are bound together by an interaction for which the strength increases with increasing particle separation. One of the consequences of this is that these individual particles cannot be observed directly. The most famous example of confinement is found in particle physics where baryons and mesons are produced by t...

We provide a review of current electron spin resonance (ESR) techniques for studying basic molecular mechanisms in membranes and proteins by using nitroxide spin labels. In particular, nitroxide spin label studies with high-field/high-frequency ESR and two-dimensional Fourier transform ESR enable one to accurately determine distances in biomolecules, unravel the details of the complex dynamics ...

We propose new approach to numerical study of quantum spin systems. Our method is based on a fact that one can use any set of states for the path integral as long as it is complete. We apply our method to one-dimensional quantum spin system with next-to-nearest neighbor interactions. We found remarkable improvement in negative sign problem.

Energy relaxation is studied in the spin-polarized disordered electron systems in the diffusive regime. We derive a quantum kinetic equation in which the kernel of the electron-electron collision integral explicitly depends on the electron magnetization. As a consequence, the inelastic scattering rate has a nonmonotonic dependence on the spin polarization of the system.

Integral encounter theory is applied to investigate spin e€ects in radical recombination. E€ects of electron spin relaxation and of S=T0 mixing by an external magnetic ®eld are considered. An analytical expression for the stationary rate constant is obtained from which appropriate conditions for experimental investigations are predicted. Ó 2000 Elsevier Science B.V. All rights reserved.

We discuss problems of functional integral formalisms in a constrained fermionic Fock space. A functional integral is set up for the Hubbard model using generalized coherent states which lie either in the constrained or in the full Fock space. The projection for the latter states is implemented through a reduction of the charge fluctuations which induce transitions between the constrained and f...

Exact conserved quantities on the cylinder I: conformal case. Abstract The nonlinear integral equations describing the spectra of the left and right (continuous) quantum KdV equations on the cylinder are derived from integrable lattice field theories, which turn out to allow the Bethe Ansatz equations of a twisted " spin −1/2 " chain. A very useful mapping to the more common nonlin-ear integral...

Anomalous dimension and higher conserved charges in the sl(2) sector of N = 4 SYM for generic spin s and twist L are described by using a novel kind of nonlinear integral equation (NLIE). The latter can be derived under typical situations of the SYM sectors, i.e. when the scattering need not depend on the difference of the rapidities and these, in their turn, may also lie on a bounded range. He...

The evaluation of a relativistic spin network for the classical case of the Lie group is given by an integral formula over copies of SU(2). For the graph determined by a 4-simplex this gives the evaluation as an integral over a space of geometries for a 4-simplex.

We derive a non-linear integral equation for the Bethe-ansatz solvable open XXZ spin chain of arbitrary length describing the lowest lying state with zero magnetization. For this case we show how to combine the integral representation with the known determinant formula of norms and scalar products. PACS: 02.30.Ik, 75.10.Pq e-mail: [email protected] e-mail: [email protected]...