Bound-state problem in quantum field theory: Linear and nonlinear dynamics

1987 ◽  
Vol 36 (8) ◽  
pp. 2506-2511 ◽  
Author(s):  
L. S. Celenza ◽  
Chueng-Ryong Ji ◽  
C. M. Shakin
Keyword(s):  
Field Theory ◽  
Nonlinear Dynamics ◽  
Quantum Field Theory ◽  
Bound State ◽  
Quantum Field ◽  
State Problem ◽  
Linear And Nonlinear ◽  
Bound State Problem

scholarly journals Resonance Electroproduction and the Origin of Mass

2020 ◽  
Vol 241 ◽  
pp. 02008
Author(s):  
Craig D. Roberts
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Relativistic Quantum ◽  
Bound State ◽  
Quantum Field ◽  
Relativistic Quantum Field Theory ◽  
State Problem ◽  
The Standard Model ◽  
Bound State Problem ◽  
The Continuum

One of the greatest challenges within the Standard Model is to discover the source of visible mass. Indeed, this is the focus of a “Millennium Problem”, posed by the Clay Mathematics Institute. The answer is hidden within quantum chromodynamics (QCD); and it is probable that revealing the origin of mass will also explain the nature of confinement. In connection with these issues, this perspective will describe insights that have recently been drawn using contemporary methods for solving the continuum bound-state problem in relativistic quantum field theory and how they have been informed and enabled by modern experiments on nucleon-resonance electroproduction.

ORTHOPOSITRONIUM LIFETIME PROBLEM

1993 ◽  
Vol 08 (17) ◽  
pp. 2859-2874 ◽  
Author(s):  
M. I. DOBROLIUBOV ◽  
S. N. GNINENKO ◽  
A. YU. IGNATIEV ◽  
V. A. MATVEEV
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Standard Treatment ◽  
Bound State ◽  
Perturbative Expansion ◽  
Quantum Field ◽  
State Problem ◽  
Decay Modes ◽  
Experimental Values ◽  
Bound State Problem

We review the present status of the problem of the six standard deviation discrepancy between the theoretical and experimental values of the orthopositronium lifetime. We discuss possible ways of its explanation and show that those invoking new decay modes are apparently closed. So the solution of this problem most probably lies either in large numerical value of the next, yet uncalculated, coefficient in the perturbative expansion of the orthopositronium decay width or in shortcomings of the standard treatment of the bound state problem in quantum field theory.

The Norms of Multimass States in Relativistic Quantum Field Theory

1974 ◽  
Vol 52 (20) ◽  
pp. 1988-1994 ◽  
Author(s):  
Roger Palmer ◽  
Yasushi Takahashi
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Relativistic Quantum ◽  
Bound State ◽  
Quantum Field ◽  
Relativistic Quantum Field Theory ◽  
Negative Norm ◽  
Quantum Numbers ◽  
Multimass System ◽  
Dynamical Origin

We examined the problem of the appearance of negative norm states in multimass models. It is shown explicitly how the bound state with the same quantum numbers as the elementary meson, can acquire the positive norm. It is inferred from our argument that the multimass system of dynamical origin can be quantized without the negative norm, contrary to the multimass system of kinematical origin.

scholarly journals EXACT-PROPAGATOR INSTANTANEOUS BETHE–SALPETER EQUATION FOR QUARK–ANTIQUARK BOUND STATES

2006 ◽  
Vol 21 (21) ◽  
pp. 1657-1673 ◽  
Author(s):  
ZHI-FENG LI ◽  
WOLFGANG LUCHA ◽  
FRANZ F. SCHÖBERL
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Bound States ◽  
Lattice Gauge Theory ◽  
Bound State ◽  
State Equation ◽  
Wave Functions ◽  
Quantum Field ◽  
Lattice Gauge ◽  
Instantaneous Approximation

Recently an instantaneous approximation to the Bethe–Salpeter formalism for the analysis of bound states in quantum field theory has been proposed which retains, in contrast to the Salpeter equation, as far as possible the exact propagators of the bound-state constituents, extracted nonperturbatively from Dyson–Schwinger equations or lattice gauge theory. The implications of this improvement for the solutions of this bound-state equation, i.e. the spectrum of the mass eigenvalues of its bound states and the corresponding wave functions, when considering the quark propagators arising in quantum chromodynamics are explored.

Bound and resonant relativistic two-particle states in scalar quantum field theory

1992 ◽  
Vol 70 (6) ◽  
pp. 412-426 ◽  
Author(s):  
Leo Di Leo ◽  
Jurij W. Darewych
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Wave Equations ◽  
Decay Channel ◽  
Hamiltonian Formalism ◽  
Bound State ◽  
Massless Scalar ◽  
Massless Scalar Field ◽  
Quantum Field ◽  
Scalar Quantum

We derive relativistic particle–antiparticle wave equations for scalar particles, [Formula: see text] and [Formula: see text], interacting via a massive or massless scalar field, χ (the Wick–Cutkosky model). The variational method, within the Hamiltonian formalism of quantum field theory is used to derive equations with and without coupling of this quasi-bound [Formula: see text] system to the χχ decay channel. Bound-state energies in the massless case are compared with the ladder Bethe–Salpeter and light-cone results. In the case of coupling to the decay channel, the quasi-bound [Formula: see text] states are seen to arise as resonances in the χχ scattering cross section. Numerical results are presented for the massive and massless χ case.

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