0 v 2 2 8 Fe b 20 03 Localization and causality for a free particle

ua nt - p h / 01 11 06 0 v 1 9 N ov 2 00 1 Localization and causality for a free particle

Theorems (most notably by Hegerfeldt) prove that an initially localized particle whose time evolution is determined by a positive Hamiltonian will violate causality. We argue that this apparent paradox is resolved for a free particle described by either the Dirac equation or the Klein-Gordon equation because such a particle cannot be localized in the sense required by the theorems.

ar X iv : h ep - p h / 03 02 18 5 v 1 2 0 Fe b 20 03 Nonlinear corrections to the DGLAP equations ; looking for the saturation limits ∗

The effects of the first nonlinear corrections to the DGLAP equations are studied in light of the HERA data. Saturation limits are determined in the DGLAP+GLRMQ approach for the free proton and for the Pb nucleus.

0 v 1 2 5 Fe b 20 03 ππ scattering S wave from the data on the reaction π − p → π 0 π 0

ar X iv : g r - qc / 0 30 21 21 v 1 2 8 Fe b 20 03 Quantizing the Line Element Field

A metric with signature (-+++) can be constructed from a metric with signature (++++) and a double-sided vector field called the line element field. Some of the classical and quantum properties of this vector field are studied.

ar X iv : c s . C G / 0 30 20 31 v 1 2 0 Fe b 20 03 Relaxed Scheduling in Dynamic Skin Triangulation ⋆

We introduce relaxed scheduling as a paradigm for mesh maintenance and demonstrate its applicability to triangulating a skin surface in R.