Time-frequency approach to relativistic correlations in quantum field theory

Relativistic Quantum Field Theory

Introduction to Relativistic Quantum Field Theory

Time evolution and Zeno effect in relativistic quantum field theory

We study the time evolution of decaying particles in the framework of certain renormalizable models of relativistic quantum field theory. Significant differences between the latter and the non-relativistic quantum mechanical case are found —in particular, regarding the so-called quantum Zeno effect. In some cases, the finite time behaviour is well defined after having performed a conventional r...

Quasiparticle excitations in relativistic quantum field theory

We analyze the particle-like excitations arising in relativistic field theories in states different than the vacuum. The basic properties characterizing the quasiparticle propagation are studied using two different complementary methods. First we introduce a frequency-based approach, wherein the quasiparticle properties are deduced from the spectral analysis of the twopoint propagators. Second,...

Unstable Systems in Relativistic Quantum Field Theory

We show how the state of an unstable particle can be defined in terms of stable asymptotic states. This general definition is used to discuss and to solve some old problems connected with the short-time and large-time behaviour of the non-decay amplitude. CERN-TH/97-246 September 1997 ⋆ Address from Sept 1st, 1997 to August 31st, 1998.