David Atkatz - Academia.edu (original) (raw)
Papers by David Atkatz
American Journal of Physics, May 1, 1995
A straightforward analysis (relying solely on publicly available information) of the γ-ray spectr... more A straightforward analysis (relying solely on publicly available information) of the γ-ray spectrum of a small piece of ‘‘trinitite,’’ the desert sand fused into glass by the world’s first nuclear explosion on July 16, 1945, allows a surprisingly accurate determination of the Trinity device’s explosive yield.
Physical review, Apr 15, 1978
We present a model for self-coupled scalar fields wh~ch, when solved subject to a self-consntent ... more We present a model for self-coupled scalar fields wh~ch, when solved subject to a self-consntent constra~llt, exh~blts the same d~agrammattc structure as the covar~antly quantized E~nste~n theory of grav~ty The gravlton appears naturally as a dynam~cal Goldstone boson. Formal expresstons for the gravlton propagator, as well as scalar-graviton and gravrton-yraviton vertices, are der~ved
American Journal of Physics, Jul 1, 1994
The application of quantum theory to the description of the universe as a whole is known as quant... more The application of quantum theory to the description of the universe as a whole is known as quantum cosmology. A brief, self-contained introduction to this field, accessible to an upper-level undergraduate physics student is presented. Perhaps the most remarkable quantum-cosmological idea—that the universe originated ex nihilo via a quantum-mechanical tunneling process—is discussed, and the probability for such a quantum cosmogenesis is calculated.
Physical Review D, 1982
We present a nonsingular model of cosmogenesis in which the Universe arises as a result of quantu... more We present a nonsingular model of cosmogenesis in which the Universe arises as a result of quantum-mechanical barrier penetration. The Universe is described throughout its evolution by a Friedmann-Robertson-Walker (FRW) metric, and the matter distribution by a perfect fiuid, whose equation of state is chosen so as to allow the tunneling to occur. Cosmic evolution proceeds in three stages; an initial static spacetime configuration tunnels into a "fireball" state in which particle creation occurs. As the fireball expands, particle creation ends, and the Universe enters the "post-big-bang" epoch of adiabatic expansion. We find that within the context of the FRW ansatz, only a spatially closed universe may originate in this manner. Implications of this creation scheme and possible generalizations are discussed. As a by-product of this investigation we find that the evolution of the Universe is described by a Gell-Manu-Low equation with the P function specified by the equation of state.
Physics Letters B, 1980
Abstract The technique of regularization by dimensional reduction is applied to source-free quant... more Abstract The technique of regularization by dimensional reduction is applied to source-free quantum gravity. The one-loop counterterms for the effective gravity-matter system are calculated in the background field formalism. The ersatz matter fields which arise in this regularization scheme are found to have no effect on the renormalizability of the theory.
Physical Review D, 1978
We present a model for self-coupled scalar fields wh~ch, when solved subject to a self-consntent ... more We present a model for self-coupled scalar fields wh~ch, when solved subject to a self-consntent constra~llt, exh~blts the same d~agrammattc structure as the covar~antly quantized E~nste~n theory of grav~ty The gravlton appears naturally as a dynam~cal Goldstone boson. Formal expresstons for the gravlton propagator, as well as scalar-graviton and gravrton-yraviton vertices, are der~ved
Journal of Physics A: Mathematical and General, 1990
ABSTRACT The authors critically examine the present theoretical understanding of the conformation... more ABSTRACT The authors critically examine the present theoretical understanding of the conformational rod-to-flexible chain crossover of a linear chain polymer in dilute solution with a good solvent. There is good evidence for weak universality in this crossover while strong universality seems unlikely from available evidence. In addition, this system should exhibit a second crossover from a Gaussian to an excluded volume. They present a scaling hypothesis for the behaviour of this second crossover and compare with the initial results of numerical simulations and with the experiment of Murakami et al. (1980).
American Journal of Physics, 1995
A straightforward analysis (relying solely on publicly available information) of the γ-ray spectr... more A straightforward analysis (relying solely on publicly available information) of the γ-ray spectrum of a small piece of ''trinitite,'' the desert sand fused into glass by the world's first nuclear explosion on July 16, 1945, allows a surprisingly accurate determination of the Trinity device's ...
American Journal of Physics, 1994
The application of quantum theory to the description of the universe as a whole is known as quant... more The application of quantum theory to the description of the universe as a whole is known as quantum cosmology. A brief, self‐contained introduction to this field, accessible to an upper‐level undergraduate physics student is presented. Perhaps the most remarkable quantum‐cosmological idea—that the universe originated ex nihilo via a quantum‐mechanical tunneling process—is discussed, and the probability for such a quantum cosmogenesis is calculated.
American Journal of Physics, May 1, 1995
A straightforward analysis (relying solely on publicly available information) of the γ-ray spectr... more A straightforward analysis (relying solely on publicly available information) of the γ-ray spectrum of a small piece of ‘‘trinitite,’’ the desert sand fused into glass by the world’s first nuclear explosion on July 16, 1945, allows a surprisingly accurate determination of the Trinity device’s explosive yield.
Physical review, Apr 15, 1978
We present a model for self-coupled scalar fields wh~ch, when solved subject to a self-consntent ... more We present a model for self-coupled scalar fields wh~ch, when solved subject to a self-consntent constra~llt, exh~blts the same d~agrammattc structure as the covar~antly quantized E~nste~n theory of grav~ty The gravlton appears naturally as a dynam~cal Goldstone boson. Formal expresstons for the gravlton propagator, as well as scalar-graviton and gravrton-yraviton vertices, are der~ved
American Journal of Physics, Jul 1, 1994
The application of quantum theory to the description of the universe as a whole is known as quant... more The application of quantum theory to the description of the universe as a whole is known as quantum cosmology. A brief, self-contained introduction to this field, accessible to an upper-level undergraduate physics student is presented. Perhaps the most remarkable quantum-cosmological idea—that the universe originated ex nihilo via a quantum-mechanical tunneling process—is discussed, and the probability for such a quantum cosmogenesis is calculated.
Physical Review D, 1982
We present a nonsingular model of cosmogenesis in which the Universe arises as a result of quantu... more We present a nonsingular model of cosmogenesis in which the Universe arises as a result of quantum-mechanical barrier penetration. The Universe is described throughout its evolution by a Friedmann-Robertson-Walker (FRW) metric, and the matter distribution by a perfect fiuid, whose equation of state is chosen so as to allow the tunneling to occur. Cosmic evolution proceeds in three stages; an initial static spacetime configuration tunnels into a "fireball" state in which particle creation occurs. As the fireball expands, particle creation ends, and the Universe enters the "post-big-bang" epoch of adiabatic expansion. We find that within the context of the FRW ansatz, only a spatially closed universe may originate in this manner. Implications of this creation scheme and possible generalizations are discussed. As a by-product of this investigation we find that the evolution of the Universe is described by a Gell-Manu-Low equation with the P function specified by the equation of state.
Physics Letters B, 1980
Abstract The technique of regularization by dimensional reduction is applied to source-free quant... more Abstract The technique of regularization by dimensional reduction is applied to source-free quantum gravity. The one-loop counterterms for the effective gravity-matter system are calculated in the background field formalism. The ersatz matter fields which arise in this regularization scheme are found to have no effect on the renormalizability of the theory.
Physical Review D, 1978
We present a model for self-coupled scalar fields wh~ch, when solved subject to a self-consntent ... more We present a model for self-coupled scalar fields wh~ch, when solved subject to a self-consntent constra~llt, exh~blts the same d~agrammattc structure as the covar~antly quantized E~nste~n theory of grav~ty The gravlton appears naturally as a dynam~cal Goldstone boson. Formal expresstons for the gravlton propagator, as well as scalar-graviton and gravrton-yraviton vertices, are der~ved
Journal of Physics A: Mathematical and General, 1990
ABSTRACT The authors critically examine the present theoretical understanding of the conformation... more ABSTRACT The authors critically examine the present theoretical understanding of the conformational rod-to-flexible chain crossover of a linear chain polymer in dilute solution with a good solvent. There is good evidence for weak universality in this crossover while strong universality seems unlikely from available evidence. In addition, this system should exhibit a second crossover from a Gaussian to an excluded volume. They present a scaling hypothesis for the behaviour of this second crossover and compare with the initial results of numerical simulations and with the experiment of Murakami et al. (1980).
American Journal of Physics, 1995
A straightforward analysis (relying solely on publicly available information) of the γ-ray spectr... more A straightforward analysis (relying solely on publicly available information) of the γ-ray spectrum of a small piece of ''trinitite,'' the desert sand fused into glass by the world's first nuclear explosion on July 16, 1945, allows a surprisingly accurate determination of the Trinity device's ...
American Journal of Physics, 1994
The application of quantum theory to the description of the universe as a whole is known as quant... more The application of quantum theory to the description of the universe as a whole is known as quantum cosmology. A brief, self‐contained introduction to this field, accessible to an upper‐level undergraduate physics student is presented. Perhaps the most remarkable quantum‐cosmological idea—that the universe originated ex nihilo via a quantum‐mechanical tunneling process—is discussed, and the probability for such a quantum cosmogenesis is calculated.