Paul Howard Frampton
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Previous Organizations / Institutes
The organizations / institutes from the scholar's other articles in the past ten years
Research Subjects
Research Interests
Paul Howard Frampton has a total of 38 co-authors. Here are the top co-authors by number of shared publications:
Shinya Matsuzaki
Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27599-3255, USA
8 shared publications- Thomas W. Kephart
Vanderbilt University
8 shared publications - Kevin J. Ludwick
Department of Physics & Astronomy University of North Carolina Chapel Hill 27599 NC
5 shared publications - David A. Eby
Department of Physics and Astronomy University of North Carolina Chapel Hill 27599-3255 NC USA
4 shared publications - Tomo Takahashi
Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27599-3255, USA
4 shared publications - Ryan M. Rohm
Department of Physics and Astronomy, UNC-Chapel Hill, NC 27599, United States
3 shared publications
Latest Publications
- Open Access
Predictions of Entropic Gravity
We discuss consequences of an entropic view of gravity, which differs in details from the original proposals of Jacobson and Verlinde. We assume the entropy is localized in the degrees of freedom of the systems interacting gravitationally. We then find there is a density-dependent minimum length for Newtonian gravity. This makes renormalizability issues irrelevant. It also follows that at nanometer scales Newton's universal law fails, black holes with mass $M_{BH} \lesssim 10^{-13} M_{\odot}$ do not exist and all Hawking radiation is at unobservably low temperature.Open AccessPredictions of Entropic Gravity
We discuss consequences of an entropic view of gravity, which differs in details from the original proposals of Jacobson and Verlinde. We assume the entropy is localized in the degrees of freedom of the systems interacting gravitationally. We then find there is a density-dependent minimum length for Newtonian gravity. This makes renormalizability issues irrelevant. It also follows that at nanometer scales Newton's universal law fails, black holes with mass $M_{BH} \lesssim 10^{-13} M_{\odot}$ do not exist and all Hawking radiation is at unobservably low temperature. - Open Access
Remarks on the Cosmological Constant
The acceleration of the surface of last scatter (SLS) must somehow reflect the energy content within it. A test particle at the SLS is assumed to experience a linear combination of two forces: one Newtonian, the other pseudo-Newtonian describable by a cosmological constant ${\Lambda}$ in general relativity. In the ${\Lambda}$ description, which is surely too unimaginative, the size of ${\Lambda}$ reflects only the comparable magnitudes of the Newtonian and pseudo-Newtonian forces; any claim of fine tuning due to quantum mechanics is probably illusory.Open AccessRemarks on the Cosmological Constant
The acceleration of the surface of last scatter (SLS) must somehow reflect the energy content within it. A test particle at the SLS is assumed to experience a linear combination of two forces: one Newtonian, the other pseudo-Newtonian describable by a cosmological constant ${\Lambda}$ in general relativity. In the ${\Lambda}$ description, which is surely too unimaginative, the size of ${\Lambda}$ reflects only the comparable magnitudes of the Newtonian and pseudo-Newtonian forces; any claim of fine tuning due to quantum mechanics is probably illusory. - Open Access
Using Newton's Law for Dark Energy
A model is introduced in which Newton's law is modified between matter and dark energy corpuscles (DECs). The model predicts that the DEC component is presently decelerating in its expansion at 14% of the magnitude of the matter expansion acceleration. In the future, expansion of the DEC universe will continue to decelerate.
Open AccessUsing Newton's Law for Dark Energy
A model is introduced in which Newton's law is modified between matter and dark energy corpuscles (DECs). The model predicts that the DEC component is presently decelerating in its expansion at 14% of the magnitude of the matter expansion acceleration. In the future, expansion of the DEC universe will continue to decelerate.
- Open Access
Entropic Inflation
One of the major pillars of modern cosmology theory is a period of accelerating expansion in the early universe. This accelerating expansion, or inflation, must be sustained for at least 30 e--foldings. One mechanism used to drive the acceleration is the addition of a new energy field, called the Inflaton; often this is a scalar field. We propose an alternative mechanism which, like our approach to explain the late-time accelerating universe, uses the entropy and temperature intrinsic to information holographically stored on a surface enclosing the observed space. The acceleration is due in both cases to an emergent entropic force, naturally arising from the information storage on the horizon.
Open AccessEntropic Inflation
One of the major pillars of modern cosmology theory is a period of accelerating expansion in the early universe. This accelerating expansion, or inflation, must be sustained for at least 30 e--foldings. One mechanism used to drive the acceleration is the addition of a new energy field, called the Inflaton; often this is a scalar field. We propose an alternative mechanism which, like our approach to explain the late-time accelerating universe, uses the entropy and temperature intrinsic to information holographically stored on a surface enclosing the observed space. The acceleration is due in both cases to an emergent entropic force, naturally arising from the information storage on the horizon.
- Open Access
Models for Little Rip Dark Energy
We examine in more detail specific models which yield a little rip cosmology, i.e., a universe in which the dark energy density increases without bound but the universe never reaches a finite-time singularity. We derive the conditions for the little rip in terms of the inertial force in the expanding universe and present two representative models to illustrate in more detail the difference between little rip models and those which are asymptotically de Sitter. We derive conditions on the equation of state parameter of the dark energy to distinguish between the two types of models. We show that coupling between dark matter and dark energy with a little rip equation of state can alter the evolution, changing the little rip into an asymptotic de Sitter expansion. We give conditions on minimally-coupled phantom scalar field models and on scalar-tensor models that indicate whether or not they correspond to a little rip expansion. We show that, counterintuitively, despite local instability, a little-rip cosmology has an infinite lifetime.
Open AccessModels for Little Rip Dark Energy
We examine in more detail specific models which yield a little rip cosmology, i.e., a universe in which the dark energy density increases without bound but the universe never reaches a finite-time singularity. We derive the conditions for the little rip in terms of the inertial force in the expanding universe and present two representative models to illustrate in more detail the difference between little rip models and those which are asymptotically de Sitter. We derive conditions on the equation of state parameter of the dark energy to distinguish between the two types of models. We show that coupling between dark matter and dark energy with a little rip equation of state can alter the evolution, changing the little rip into an asymptotic de Sitter expansion. We give conditions on minimally-coupled phantom scalar field models and on scalar-tensor models that indicate whether or not they correspond to a little rip expansion. We show that, counterintuitively, despite local instability, a little-rip cosmology has an infinite lifetime.
- Open Access
Dark Matter from Binary Tetrahedral Flavor Symmetry
The minimal renormalizable T'xZ2 model (MRT'M) is slightly extended in its Higgs scalar sector such that the abelian part of the flavor symmetry enlarges to (Z2xZ2'). All standard model and original MRT'M states will transform trivially under Z2'. Inspired by the Valencia group's A4 model building, we propose a T' WIMP candidate as the lightest Z2' odd scalar. This extension of the prior MRT'M model maintains the successful predictions for the neutrino mixing matrix and the Cabibbo angle, and provides an attractive candidate for dark matter (Phi_WIMP) with M_Phi \simeq 780 GeV.
Open AccessDark Matter from Binary Tetrahedral Flavor Symmetry
The minimal renormalizable T'xZ2 model (MRT'M) is slightly extended in its Higgs scalar sector such that the abelian part of the flavor symmetry enlarges to (Z2xZ2'). All standard model and original MRT'M states will transform trivially under Z2'. Inspired by the Valencia group's A4 model building, we propose a T' WIMP candidate as the lightest Z2' odd scalar. This extension of the prior MRT'M model maintains the successful predictions for the neutrino mixing matrix and the Cabibbo angle, and provides an attractive candidate for dark matter (Phi_WIMP) with M_Phi \simeq 780 GeV.
- 2 September 2011
- Published by Springer Nature in The European Physical Journal C
- Vol. 71 (9) , 1-6
Seeking evolution of dark energy
- 2 September 2011
- Published by Springer Nature in The European Physical Journal C
- Vol. 71 (9) , 1-6
Seeking evolution of dark energy
- Open Access
Seeking Evolution of Dark Energy
We study how observationally to distinguish between a cosmological constant (CC) and an evolving dark energy with equation of state $\omega(Z)$. We focus on the value of redshift Z* at which the cosmic late time acceleration begins and $\ddot{a}(Z^{*}) = 0$. Four $\omega(Z)$ are studied, including the well-known CPL model and a new model that has advantages when describing the entire expansion era. If dark energy is represented by a CC model with $\omega \equiv -1$, the present ranges for $\Omega_{\Lambda}(t_0)$ and $\Omega_m(t_0)$ imply that Z* = 0.743 with 4% error. We discuss the possible implications of a model independent measurement of Z* with better accuracy.Open AccessSeeking Evolution of Dark Energy
We study how observationally to distinguish between a cosmological constant (CC) and an evolving dark energy with equation of state $\omega(Z)$. We focus on the value of redshift Z* at which the cosmic late time acceleration begins and $\ddot{a}(Z^{*}) = 0$. Four $\omega(Z)$ are studied, including the well-known CPL model and a new model that has advantages when describing the entire expansion era. If dark energy is represented by a CC model with $\omega \equiv -1$, the present ranges for $\Omega_{\Lambda}(t_0)$ and $\Omega_m(t_0)$ imply that Z* = 0.743 with 4% error. We discuss the possible implications of a model independent measurement of Z* with better accuracy. - 31 March 2011
- Published by Elsevier in Astroparticle Physics
- Vol. 34 (8) , 617-619
Number and entropy of halo black holes
- 31 March 2011
- Published by Elsevier in Astroparticle Physics
- Vol. 34 (8) , 617-619
Number and entropy of halo black holes
- Open Access
LHC Higgs Production and Decay in the T' Model
At $\sqrt{s} = 7$ TeV, the standard model needs at least $10\, (fb)^{-1}$ integrated luminosity at LHC to make a definitive discovery of the Higgs boson. Using binary tetrahedral ($T^{'}$) discrete flavor symmetry, we discuss how the decay of the lightest $T'$ Higgs into $\gamma\,\gamma$ can be effectively enhanced and dominate over its decay into $b \, \bar{b}$. Since the two-photon final state allows for a clean reconstruction, a decisive Higgs discovery may be possible at 7 TeV with the integrated luminosity only of $\sim 1\, (fb)^{-1}$.Open AccessLHC Higgs Production and Decay in the T' Model
At $\sqrt{s} = 7$ TeV, the standard model needs at least $10\, (fb)^{-1}$ integrated luminosity at LHC to make a definitive discovery of the Higgs boson. Using binary tetrahedral ($T^{'}$) discrete flavor symmetry, we discuss how the decay of the lightest $T'$ Higgs into $\gamma\,\gamma$ can be effectively enhanced and dominate over its decay into $b \, \bar{b}$. Since the two-photon final state allows for a clean reconstruction, a decisive Higgs discovery may be possible at 7 TeV with the integrated luminosity only of $\sim 1\, (fb)^{-1}$.