arXiv subjects

H. M. Fried

Publications and source records attributed to H. M. Fried.

29 records · Page 2Linked to original sources

arXiv2009

Gauge Invariant Summation of All QCD Virtual Gluon Exchanges

The interpretation of virtual gluons as ghosts in the non-linear gluonic structure of QCD permits the formulation and realization of a manifestly gauge-invariant and Lorentz covariant theory of interacting quarks/anti-quarks, for all values of coupling. The simplest example of quark/anti-quark scattering in a high-energy, quenched, eikonal model at large coupling is shown to be expressible as a set of finite, local integrals which may be evaluated numerically; and before evaluation, it is clear that the result will be dependent only on, and is damped by increasing momentum transfer, while displaying physically-reasonable color dependence in a manner underlying the MIT Bag Model and an effective, asymptotic freedom. A similar but more complicated integral will result from all possible gluonic-radiative corrections to this simplest eikonal model. Our results are compatible with an earlier, field-strength analysis of Reinhardt et al.

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arXiv2008

Bloch-Nordsieck Estimates of High-Temperature QED

In anticipation of a subsequent application to QCD, we consider the case of QED at high temperature. We introduce a Fradkin representation into the exact, Schwingerian, functional expression of a fermion propagator, as well as a new and relevant version of the Bloch-Nordsieck (BN) model, which extracts the soft contributions of every perturbative graph, in contradistinction to the assumed separation of energy scales of previous semi-perturbative treatments. Our results are applicable to the absorption of a fast particle which enters a heat bath, as well as to the propagation of a symmetric pulse within the thermal medium due to the appearance of an instantaneous, shock-wave-like source acting in the medium. An exponentially-decreasing time dependence of the incident particle's initial momentum combines with a stronger decrease in the particle's energy, estimated by a sum over all Matsubara frequencies, to model an initial "fireball", which subsequently decays in a Gaussian fashion. When extended to QCD, qualitative applications could be made to RHIC scattering, in which a fireball appears, expands and is damped away.

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arXiv2007

Quantum Tachyon Dynamics

It is suggested that charged tachyons of extremely large mass M could not only contribute to the dark matter needed to fit astrophysical observations, but could also provide an explanation for gamma ray bursts and ulta high energy cosmic rays. The present paper defines a quantum field theory of tachyons, particles similar to ordinary leptons, but with momenta larger than energy. The theory is invariant under the full CPT transformation, but separately violates P and T invariance. Micro causality is broken for space-time intervals smaller than 1/M, but is effectively preserved for larger separations. Charged fermionic, rather than charged scalar tachyons are considered in order to minimize the probability of Cerenkov-like radiation by the tachyon, thereby permitting a high energy tachyon to retain its energy over galactic distances. Topics treated include the choice and Schwinger Action Principle variations of an appropriate Lagrangian, spinorial wave functions, relevant Green's functions, a functional description of an S-Matrix and generating functional, and a variety of interesting kinematical processes, including photon emission and reabsorption, and relevant annihilation and scattering effects. A version of Ehrenfest's theorem is developed, in order to provide a foundation for a classical description of charged tachyons in an external electromagnetic field. Applications are then made to three outstanding astrophysical puzzles : dark matter, gamma ray bursts and ultra high energy cosmic rays.

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arXiv2005

Quantum Tachyon Dynamics

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arXiv2003

Possibilities of a QED-Based Vacuum Energy

A QED-based bootstrap mechanism, appearing at sufficiently small space-time scales, is suggested as an explanation for the "dark" vacuum energy that may be able to accelerate the universe. Very small-scale vacuum currents are allowed to generate small-scale electromagnetic fields, which become significant near the light cone. The resulting lepton-pair production, some of which may be tachyonic, has ramifications for the convergence of all QED perturbative processes, as well as providing possible mechanisms for "dark" matter, galactic gamma-ray bursts, and ultra-high-energy cosmic rays.

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arXiv2003

Towards a QED-Based Vacuum Energy

A QED-based mechanism, breaking translational invariance of the vacuum at sufficiently small distance scales, is suggested as an explanation for the vacuum energy pressure that accelerates the universe. Very-small-scale virtual vacuum currents are assumed to generate small-scale electromagnetic fields corresponding to the appearance of a 4-potential $A_μ^{ext} (x)$, which is itself equal to the vev of the operator $ A_μ(x)$ in the presence of that $A_μ^{ext}(x)$. The latter condition generates a bootstrap-like equation for $A_μ^{ext}(x)$ which has an approximate, tachyonic-like solution corresponding to propagation outside the light cone, and damping inside; this solution is given in terms of a mass parameter M that turns out to be on the order of the Planck mass if only the simplest, electron vacuum-bubble is included; if the muon and tau bubbles are included, M decreases to $\sim 10^6 - 10^7$ GeV. A multiplicative 4-vector $v_μ$, whose magnitude is determined by a comparison with the average mass density needed to produce the observed acceleration is introduced, and characterizes the distance d over which the fields so produced may be expected to be coherent; the present analysis suggests that d can lie anywhere in the range from $10^{-5} cm$ (corresponding to a "spontaneous vacuum phase change") to $10^{-13}cm$ (representing a "polarization of the QED vacuum" by quark-antiquark pairs of the QCD vacuum). Near the light-cone, such electric fields become large, introducing the possibility of copious charged-particle pair production, whose back-reaction-fields tend to diminish the vacuum electric field. The possibility of an experimental test of the resulting plasma at large momentum transfers is discussed.

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arXiv2002

Summing all the eikonal graphs. II

A physically reasonable model is introduced in order to estimate, in a functional way, the vast number of distinct graphs which are conventionally neglected in eikonal scattering models that lead to total cross sections increasing with energy in the form of the Froissart bound.

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arXiv2002

Non trivial generalizations of the Schwinger pair production result

We present new, non trivial generalizations of the recent Tomaras, Tsamis and Woodard extension of the original Schwinger formula for charged pair production in a constant field.

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arXiv2001

The One Loop Effective Action of QED for a General Class of Electric Fields

We compute the effective action of QED at one loop order for an electric field which points in the $\hat{z}$ direction and depends arbitrarily upon the light cone time coordinate, $x^+ = (x^0 + x^3)/\sqrt{2}$. This calculation generalizes Schwinger's formula for the vacuum persistence probability in the presence of a constant electric field.

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arXiv1997

Non-Abelian Eikonal Formalism in QCD_4

Using a new technique for the extraction of leading-log energy dependence from the non-Abelian portion of quark-line interactions, hadronic scattering amplitudes may be represented in terms of functional integrals over gluonic material exchanged between scattering quarks. If that material is further represented by a condensed tube of gluonic flux (obtained by dimensional transmutation), these functional integrals will produce effective propagators corresponding to plasma oscillations, or ``condensons'', in this condensed gluonic material. These condensons yield a non-zero, non-tachyonic, finite, gauge-invariant contribution only when the gluonic flux tube corresponds to a ``rigid string'' of negligible thickness, so that this formalism provides a natural mechanism for a ``dynamical string'' in QCD4. Summation over a subset of such relevant condensons (at least in SU(2)) generates a form of the Donnachie-Landshoff Pomeron for the scattering amplitude. Other, non-condensate approaches are also available.

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arXiv1996

Non-abelian Eikonals

A functional formulation and partial solution is given of the non-abelian eikonal problem associated with the exchange of non-interacting, charged or colored bosons between a pair of fermions, in the large $s$/small $t$ limit. A simple, functional ``contiguity" prescription is devised for extracting those terms which exponentiate, and appear to generate the leading, high-energy behavior of each perturbative order of this simplest non-abelian eikonal function; the lowest non-trivial order agrees with the corresponding SU(N) perturbative amplitude, while higher-order contributions to this eikonal generate an ``effective Reggeization" of the exchanged bosons, resembling previous results for the perturbative amplitude. One exact and several approximate examples are given, including an application to self-energy radiative corrections. In particular, for this class of graphs and to all orders in the coupling, we calculate the leading-log eikonal for SU(2). Based on this result, we conjecture the form of the eikonal scattering amplitude for SU(N).

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