619 research outputs found
Framework for finite alternative theories to a quantum field theory
Using the path-integral formalism, we generalize the 't Hooft-Veltman method
of unitary regulators to put forward a framework for finite, alternative
quantum theories to a given quantum field theory. Feynman-like rules of such a
finite, alternative quantum theory lead to alternative, perturbative Green
functions. Which are acceptably regularized perturbative expansions of the
original Green functions, causal, and imply no unphysical free particles. To
demonstrate that the proposed framework is feasible, we take the quantum field
theory of a single, self-interacting real scalar field and show how we can
alter, covariantly and locally, its free-field Lagrangian to obtain finite,
alternative perturbative Green functions.Comment: 14 pages v.2: 15 pages; modified generating functional to include
renormalization constants; v.3: some small corrections to synchronize with
the printed versio
Two basic problems posed by quantum scattering of fundamental particles
We put forward a finite theory of quantum scattering of fundamental particles
without using auxiliary particles. It suggests that to avoid ultraviolet
divergencies and model faster-than-light effects it suffices to appropriately
change only the free-field Lagrangians while retaining their locality in
space-time and Lorentz invariance. Using functions of two independent
four-vector variables, we base this finite theory on the path-integral
formalism on the four-dimensional space-time and the
Lehmann-Symanzik-Zimmermann reduction formula.Comment: 19 pages, no figure
Regularization of QED by a generalized 't Hooft and Veltman method
Generalizing the 't Hooft and Veltman method of unitary regulators, we
demonstrate for the first time the existence of local, Lorentz-invariant,
physically motivated Lagrangians of quantum-electrodynamic phenomena such that:
(i) Feynman diagrams are finite and equal the diagrams of QED but with
regularized propagators. (ii) N-point Green functions are causal. (iii)
S-matrix relates only electrons, positrons and photons, is unitary and
Lorentz-invariant, and conserves charge and total four-momentum.Comment: RevTeX, 5 pages, nofigures; changed title and changed and added few
sentences to stress that this is an example, and to shortly explain the
framework of the original 't Hooft and Veltman regularization metho
Framework for finite alternative theories to a quantum field theory. II-Unitarity
We generalized the 't Hooft-Veltman method of unitary regulators to put
forward a path-integral framework for finite, alternative theories to a given
quantum field theory. And we demonstrated that the proposed framework is
feasible by providing a finite alternative to the quantum field theory of a
single, self-interacting real scalar field. Here we give two properties of
self-energy that make the corresponding scattering matrix unitary. We show that
the perturbative self-energy has these two properties at least up to the second
order in the coupling constant
Perturbative S-matrices that depend on parameters of a realistic regularization
We propose a partial answer to the question of what kind of ultrahigh-energy
physics has to be taken into account to circumvent the appearance of
ultraviolet divergencies; a more than sixty years old open question in quantum
electrodynamics. To this end we introduce a new theoretical concept to the
theory of quantum scattering: Perturbative S-matrices that depend on parameters
of a realistic regularization--realistic in the sense of Pauli and Villars
[Rev. Mod. Phys. 21, 434 (1949)]. We expect that these additional parameters
may provide some new information about the physics of quantum scattering. There
are such perturbative S-matrices also in the presence of non-renormalizable
interaction terms with no counterterms
Applications of the Lorentz-Abraham-Dirac equation in long-term dynamics
To improve the presentation we modified the title and used the framework of
perturbation modeling of long-term dynamics so as to present the
Lorentz-Abraham-Dirac equation as the lowest order, asymptotic differential
relation for the velocity of a charged point-like mass. We formulated two
propositions and added two references.Comment: PACS numbers: 03.50.De; 45.50.-j; 11.30.-j; 29.20.-c; 45.05.+x
Keywords: Radiation-reaction force, particle trajectory; accelerators. arXiv
admin note: substantial text overlap with arXiv:1005.394
Realistic regularization of the QED Green functions
Generalizing the 't Hooft and Veltman method of unitary regulators, we
demonstrate for the first time the existence of local, Lorentz-invariant,
physically motivated Lagrangians of quantum-electrodynamic phenomena such that:
(i) Feynman diagrams are finite and equal the diagrams of QED but with
regularized propagators. (ii) N-point Green functions are C-, P-, and
T-invariant up to a phase factor, Lorentz-invariant and causal. (iii) No
auxiliary particles or parameters are introduced
Modeling quantum scattering of fundamental particles by classical, deterministic processes
We point out that results obtained by M. Ribaric and L. Sustersic,
hep-th/0403084, and by M. Blasone, P. Jizba and H. Kleinert, quant-ph/0409021,
suggest that the path-integral formalism is the key to a derivation of quantum
physics from classical, deterministic physics in the four-dimensional
space-time. These results and the 't Hooft conjecture, hep-th/0104219, suggest
to consider a relativistic, non-material medium, an ether, as a base for
non-local hidden-variable models of the physical universe
Transport-theoretic Extensions of Quantum Field Theories
We propose a new, transport-theoretic (tt) class of relativistic extensions
of quantum field theories of fundamental interactions. Its concepts are
inspired by Feynman's atomistic idea about the physical world and by the
extension of fluid dynamics to shorter distances through the Boltzmann
transport equation. The extending tt Lagrangians imply the original Lagrangians
as path-integralwise approximations. By constructing a tt Lagrangian that
extends a general gauge-invariant Lagrangian, we show that a tt extension of
the standard model is feasible. We define a tt Lagrangian in terms of tt fields
of the spacetime variable and an additional, four-vector variable. We explain
the fields of quantum field theories as certain covariant, local averages of tt
fields. Only two tt fields may be needed for modeling fundamental interactions:
(i) a four-vector one unifying all fundamental forces, and (ii) a
two-component-spinor one unifying all fundamental matter particles. We comment
on the new physics expected within the tt framework put forward, and point out
some open questions.Comment: 36 pages, no pictures, plain Te
Search for an equation of motion of a classical pointlike charge
In 1892 H.A. Lorentz started the search for a classical equation of motion
for pointlike charged particles that takes into account the radiation reaction
force. This search culminated in the Lorentz-Abraham-Dirac equation of motion,
which is not satisfactory since it exhibits self-acceleration causing runaway
solutions. In spite of ongoing efforts for more than a century, there is yet no
acceptable classical equation of motion for a pointlike charge, cf. the recent
paper by Rohrlich and the comments about his proposal. So, it is still an open
question how to augment continuous classical electrodynamics with the physical
concept of pointlike charged particles. The pointlike charge is presently only
a common and handy computational device, which we generalized by the expansions
in terms of co-moving moments of time-dependent, moving charges and currents
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