arXiv subjects

George Chapline

Publications and source records attributed to George Chapline.

33 records · Page 2Linked to original sources

arXiv2007

Superfluid Transition in a Chiron Gas

Low temperature measurements of the magnetic susceptibility of LSCO suggest that the superconducting transition is associated with the disappearance of a vortex liquid. In this note we wish to draw attention to the fact that spin-orbit-like interactions in a poorly conducting layered material can lead to a new type of quantum ground state with spin polarized soliton-like charge carriers as the important quantum degree of freedom. In 2-dimensions these solitons are vortex-like, while in 3-dimensional systems they are monopole-like. In either case there is a natural mechanism for the pairing of spin up and spin down solitons, and we find that at low temperatures there is a cross-over transition as a function of carrier density between a state where the solitons are free and a condensate state where the spin up and spin down solitons in neighboring layers are paired.

cond-mat.supr-con↗

arXiv2006

Blueprint for a rotating Univers

A solution of the vacuum Einstein equations with a cosmological constant is exhibited which can perhaps be used to describe the interior of compact rotating objects, and may also provide a description of our universe on length scales approaching the size of the de Sitter horizon.

astro-ph↗

arXiv2005

Tommy Gold Revisited: Why Does Not The Universe Rotate?

Understanding gravitational collapse requires understanding how $\sim 10^{58}$ nucleons can be destroyed in $\sim 10^{-5}$ seconds. The recent proposal that the endpoint of gravitational collapse can be a "dark energy star" implies that the mass-energy of the nucleons undergoing gravitational collapse can be converted to vacuum energy when one gets near to conditions where classical general relativity predicts that a trapped surface would form. The negative pressure associated with a large vacuum energy prevents an event horizon from forming, thus resolving the long-standing puzzle as to why gravitational collapse always leads to an explosion. An indirect consequence is that the reverse process - creation of matter from vacuum energy - should also be possible. Indeed this process may be responsible for the "big bang". In this new cosmology the observable universe began as a fluctuation in an overall steady state universe. The fluctuations in the CMB in this picture are the result of quantum turbulence associated with vorticity. This explanation for the CMB fluctuations is superior to inflationary scenarios because there is a natural explanation for both the level of CMB fluctuations and the deviation from a scale invariant spectrum at large scales.

astro-ph↗

arXiv2003

Nearly Insulating Strongly Correlated Systems: Gossamer Superconductors and Metals

Recently a new phenomenological Hamiltonian was proposed to describe the superconducting cuprates in which correlations and on-site Coulomb repulsion are introduced by partial Gutzwiller projection. This Gossamer Hamiltonian has an exact ground state and differs from the t-J and Hubbard Hamiltonians in possessing a powerful attractive interaction among electrons responsible for Cooper pairing in the d-wave channel. It is a faithful description for a superconductor with strong on-site electronic repulsion. The superconducting tunneling gap remains intact and despite on-site repulsion. Near half-filling the Gossamer superconductor with strong repulsion has suppressed photoemission intensities and superfluid density, is unstable toward an antiferromagnetic insulator and possesses an incipient Mott-Hubbard gap. The Gossamer technique can be applied to metallic ground states thus possibly serving as an apt description of strongly correlated metals. Such a Gossamer metallic phase, just as the Gossamer superconducting one, becomes arbitrarily hard to differentiate from an insulator as one turns the Coulomb correlations up near half-filling. Both the metallic and superconducting states undergo a quantum phase transition to an antiferromagnetic insulator as one increases the on-site Coulomb repulsion. In the Gossamer model we reach the critical point at half-filling by fully projecting out the double occupancy. Such a critical point might be the Anderson Resonating Valence bond state.

cond-mat.str-el↗

arXiv2003

On Gossamer Metals and Insulating Behavior

We extend the Gossamer technique recently proposed to describe superconducting ground states to metallic ground states. The gossamer metal in a single band model will describe a metallic phase that becomes arbitrarily hard to differentiate from an insulator as one turns the Coulomb correlations up. We were motivated by the phase diagram of V$_2$O$_3$ and f-electron systems which have phase diagrams in which a line of first order metal-insulator transition ends at a critical point above which the two phases are indistinguishable. This means that one can go continuously from the metal to the ``insulator'', suggesting that they might be the same phase.

cond-mat.str-el↗

arXiv1999

Quantum Mechanics as Information Fusion

We provide evidence that quantum mechanics can be interpreted as a rational algorithm for finding the least complex description for the correlations in the outputs of sensors in a large array. In particular, by comparing the self-organization approach to solving the Traveling Salesman Problem with a solution based on taking the classical limit of a Feynman path integral, we are led to a connection between the quantum mechanics of motion in a magnetic field and self-organized information fusion.

quant-ph↗

arXiv1999

Minimum Energy Information Fusion in Sensor Networks

In this paper we consider how to organize the sharing of information in a distributed network of sensors and data processors so as to provide explanations for sensor readings with minimal expenditure of energy. We point out that the Minimum Description Length principle provides an approach to information fusion that is more naturally suited to energy minimization than traditional Bayesian approaches. In addition we show that for networks consisting of a large number of identical sensors Kohonen self-organization provides an exact solution to the problem of combining the sensor outputs into minimal description length explanations.

adap-org↗

arXiv1999

A Natural Cosmological Model with Omega_matter <1

Flat cosmological models with a cosmological constant on the order of the Einstein-de Sitter critical density are enigmatic in the sense that there does not appear to be any natural explanation for why there should be a cosmological constant with such a magnitude. As a perhaps more natural alternative we propose a spatially homogeneous isotropic Omega=1 universe containing cold matter and with a vacuum energy that varies inversely with the square of the Robertson-Walker scale parameter. This leads to a cosmological model that in some ways resembles yet is distinct from an open Friedmann universe with no cosmological constant. Some possibilities for distinguishing between a flat universe with a cosmological constant and a flat universe where the vacuum energy is inversely proportional to the square of the scale parameter are discussed.

astro-ph↗

arXiv1998

The Vacuum Energy in a Condensate Model for Spacetime

It is shown that a simple model for 4-dimensional quantum gravity based on a 3-dimensional generalization of anyon superconductivity can be regarded as a discrete form of Polyakov's string theory. This suggests that there is a universal negative pressure that is on the order of the string tension divided by the square of the Robertson-Walker scale factor. This is in accord with recent observations of the brightness of distant supernovae, which suggest that at the present time there is a vacuum energy whose magnitude is close to the mass density of an Einstein-de Sitter universe.

hep-th↗

arXiv1998

Moyal Quantization, Holography, and the Quantum Geometry of Surfaces

An elementary introduction is provided to the phase space quantization method of Moyal and Wigner. We generalize the method so that it applies to 2-dimensional surfaces, where it has an interesting connection with quantum holography. In the case of Riemann surfaces the connection between Moyal quantization and holography provides new insights into the Torelli theorem and the quantization of non-linear integrable models. Quantum holography may also serve as a model for a quantum theory of membranes.

hep-th↗

arXiv1998

The Black Hole Information Puzzle and Evidence for a Cosmological Constant

Recent hints from observations of distant supernovae of a positive cosmological constant with magnitude comparable to the average density of matter seem to point in the direction of a two fluid model for spacetime; where the "normal" component consists of ordinary matter, while the "superfluid" component is a zero entropy condensate. Such a two fluid model for spacetime provides an immediate and simple explanation for why information seems to be lost when objects fall into a classical black hole.

hep-th↗

arXiv1998

A Unique Theory of Gravity and Matter

The author has previously suggested that the ground state for 4-dimensional quantum gravity can be represented as a condensation of non-linear gravitons connected by Dirac strings. In this note we suggest that the low-lying excitations of this state can be described by a quasi-topological action corresponding to a trilinear coupling of solitonic 8-branes and 7-branes. It is shown that when the 7-brane excitations are neglected, the effective action can be interpreted as a theory of conformal gravity in four dimensions. This suggests that ordinary gravity as well as supersymmetric matter and phenomenological gauge symmetries arise from the spontaneous breaking of topological invariance.

hep-th↗

arXiv1997

Sentient Networks

In this paper we consider the question whether a distributed network of sensors and data processors can form "perceptions" based on the sensory data. Because sensory data can have exponentially many explanations, the use of a central data processor to analyze the outputs from a large ensemble of sensors will in general introduce unacceptable latencies for responding to dangerous situations. A better idea is to use a distributed "Helmholtz machine" architecture in which the collective state of the network as a whole provides an explanation for the sensory data.

adap-org↗

arXiv1996

Spontaneous Origin of Topological Complexity in Self-Organizing Neural Networks

Attention is drawn to the possibility that self-organizing biological neural networks could spontaneously acquire the capability to carry out sophisticated computations. In particular it is shown that the effective action governing the formation of synaptic connections in models of networks of feature detectors that encorporate Kohonen-like self-organization can spontaneously lead to structures that are topologically nontrivial in both a 2-dimensional and 4-dimensional sense. It is suggested that the appearance of biological neural structures with a nontrivial 4-dimensional topology is the fundamental organizational principle underlying the emergence of advanced cognitive capabilities.

adap-org↗

arXiv1996

The Monster Sporadic Group and a Theory Underlying Superstring Models

The pattern of duality symmetries acting on the states of compactified superstring models reinforces an earlier suggestion that the Monster sporadic group is a hidden symmetry for superstring models. This in turn points to a supersymmetric theory of self-dual and anti-self-dual K3 manifolds joined by Dirac strings and evolving in a 13 dimensional spacetime as the fundamental theory. In addition to the usual graviton and dilaton this theory contains matter-like degrees of freedom resembling the massless states of the heterotic string, thus providing a completely geometric interpretation for ordinary matter.

hep-th↗