arXiv subjects

J. C. Phillips

Publications and source records attributed to J. C. Phillips.

At least 73 records · Page 4Linked to original sources

arXiv2010

Globalization and Glassy Ideality of the Web of Twentieth Century Science

Scientific communication is an essential part of modern science: whereas Archimedes worked alone, Newton (correspondence with Hooke, 1676) acknowledged that "If I have seen a little further, it is by standing on the shoulders of Giants." How is scientific communication reflected in the patterns of citations in scientific papers? How have these patterns changed in the 20th century, as both means of communication and individual transportation changed rapidly, compared to the earlier post-Newton 18th and 19th centuries? Here we discuss a glass model for scientific communications, based on a unique 2009 scientometric study of 25 million papers and 600 million citations that encapsulates the epistemology of modern science. The glass model predicts and explains, using no adjustable parameters, a surprisingly universal internal structure in the development of scientific research, which is essentially constant across the natural sciences, but which because of globalization changed qualitatively around 1960. Globalization corresponds physically to anomalous superdiffusion, which has been observed near the molecular glass transition, and can enhance molecular diffusion by factors as large as 100.

physics.soc-ph↗

arXiv2010

Microscopic Aspects of Stretched Exponential Relaxation (SER) in Homogeneous Molecular and Network Glasses and Polymers

Because the theory of SER is still a work in progress, the phenomenon itself can be said to be the oldest unsolved problem in science, as it started with Kohlrausch in 1847. Many electrical and optical phenomena exhibit SER with probe relaxation I(t) ~ exp[-(t/τ)β], with 0 < β < 1. Here τ is a material-sensitive parameter, useful for discussing chemical trends. The "shape" parameter β is dimensionless and plays the role of a non-equilibrium scaling exponent; its value, especially in glasses, is both practically useful and theoretically significant. The mathematical complexity of SER is such that rigorous derivations of this peculiar function were not achieved until the 1970's. The focus of much of the 1970's pioneering work was spatial relaxation of electronic charge, but SER is a universal phenomenon, and today atomic and molecular relaxation of glasses and deeply supercooled liquids provide the most reliable data. As the data base grew, the need for a quantitative theory increased; this need was finally met by the diffusion-to-traps topological model, which yields a remarkably simple expression for the shape parameter β, given by d*/(d* + 2). At first sight this expression appears to be identical to d/(d + 2), where d is the actual spatial dimensionality, as originally derived. The original model, however, failed to explain much of the data base. Here the theme of earlier reviews, based on the observation that in the presence of short-range forces only d* = d = 3 is the actual spatial dimensionality, while for mixed short- and long-range forces, d* = fd = d/2, is applied to four new spectacular examples, where it turns out that SER is useful not only for purposes of quality control, but also for defining what is meant by a glass in novel contexts. (Please see full abstract in main text)

cond-mat.soft↗

arXiv2009

Topology and the Web of Twentieth Century Science

Scientific communication is an essential part of modern science: whereas Archimedes worked alone, Newton (1676) acknowledged that "If I have seen a little further, it is by standing on the shoulders of Giants." How is scientific communication reflected in the patterns of citations in scientific papers? How have these patterns changed in the 20th century, as both means of communication and individual transportation changed rapidly, compared to the earlier post-Newton 18th and 19th centuries? Here we discuss a physical model for scientific communications, based on an informetric study of 25 million papers and 600 million citations; the physical model itself relies on analogies with glass relaxation, where virtually identical patterns have been identified in 50 well designed experiments. The model reveals a surprisingly universal internal structure in the development of scientific research, which is essentially constant across the natural sciences, but which changed qualitatively around 1960.

physics.gen-ph↗

arXiv2009

Topological Theory of Ceramic High Temperature Superconductors

Optimally doped ceramic superconductors (cuprates, pnictides, ...) exhibit transition temperatures Tc much larger than strongly coupled metallic superconductors like Pb (Tc= 7.2K, Eg/kTc = 4.5), and exhibit many universal features that appear to contradict the BCS theory of superconductivity based on attractive electron-phonon pairing interactions. Here I argue that this paradoxical simplicity is plausibly resolved within the framework of the Pauling-Phillips self-organized, hard-wired dopant network model of ceramic superconductors, which has previously explained many features of the normal-state transport properties of these materials and successfully predicted strict lowest upper bounds for Tc in the cuprate and pnictide families.

cond-mat.supr-con↗

arXiv2009

Universal Non-Landau, Self-Organized, Lattice Disordering Percolative Dopant Network Sub-Tc Phase Transitions in Ceramic Superconductors

Ceramic superconductors (cuprates, pnictides, ...) exhibit universal features in both Tcmax and in their planar lattice disordering measured by EXAFS, as reflected by three phase transitions. The two highest temperature transitions are known to be associated with formation of pseudogaps and superconductive gaps, with corresponding Landau order parameters, but no new gap is associated with the third transition below Tc. It is argued that the third transition is a dopant glass transition, which is remarkably similar to transitions previously observed in chalcogenide and oxide alloy network glasses (like window glass).

cond-mat.supr-con↗

arXiv2009

Prediction of High Transition Temperatures in Ceramic Superconductors

The prediction of transition temperatures can be regarded in several ways, either as an exacting test of theory, or as a tool for identifying theoretical rules for defining new homology models. Popular "first principle" methods for predicting transition temperatures in conventional crystalline superconductors have failed for cuprate HTSC, as have parameterized models based on CuO2 planes (with or without apical oxygen). Following a path suggested by Bayesian probability, we find that the glassy, self-organized dopant network percolative model is so successful that it defines a new homology class appropriate to ceramic superconductors. The reasons for this success are discussed, and a critical comparison is made with previous theories. The predictions are successful for all ceramics, including new non-cuprates based on FeAs in place of CuO2.

cond-mat.supr-con↗

arXiv2009

Microscopic Aspects of Stretched Exponential Relaxation (SER)

The Scher-Lax-Phillips (SLP) universal minimalist model quantitatively explains stretching fractions beta(Tg) for a wide variety of relaxation experiments (nearly 50 altogether) on electronic and molecular glasses and deeply supercooled liquids by assuming that quasi-particle excitations indexed by Breit-Wigner channels diffuse to traps (sinks). This model is effective here in discussing in detail three experiments: luminescence in isoelectronic Zn(Se,Te) alloys, fibrous relaxation in orthoterphenyl (OTP) and related glasses and melts up to 1.15Tg, and relaxation of binary chalcogen melts probed by spin-polarized neutrons (T as high as 1.5Tg). The model is also compared to several other recent theories.

cond-mat.other↗

arXiv2008

High Temperature Cuprate-Like Superconductivity at Surfaces and Interfaces

The realization of high-transition-temperature superconductivity (HTSC) confined to nanometre-sized interfaces has been a long-standing goal because of potential applications and the opportunity to study quantum phenomena in reduced dimensions. Here we discuss HTSC at free surfaces, interfaces, and nanoscale cluster surfaces, and show that the percolative self-organized model of bulk HTSC also gives an excellent description of HTSC in quasi-two-dimensional contexts.

cond-mat.supr-con↗

arXiv2008

Hydroanalysis of Animal Lysozymes c and Human Defensins a

Proteins appear to be the most dramatic natural example of self-organized criticality (SOC), a concept that explains many otherwise apparently unlikely phenomena. Protein functionality is dominated by long range hydro(phobic/philic) interactions which both drive protein compaction and mediate protein-protein interactions. In contrast to previous reductionist short range hydrophobicity scales, the holistic Moret-Zebende hydrophobicity scale represents a hydroanalytic tool that bioinformatically quantifies SOC in a way fully compatible with evolution. Hydroprofiling identifies chemical trends in the activities and substrate binding abilities of model enzymes and antibiotic animal lysozymes c and antibiotic human defensins, which have been the subject of tens of thousands of experimental studies. The analysis is simple and easily performed, and immediately yields insights not obtainable by traditional methods based on short-range real-space interactions, as described either by classical force fields (CFF) used in molecular dynamics simulations (MDS), or hydrophobicity scales based on transference energies from water to organic solvents.

cond-mat.soft↗

arXiv2008

Functionality and Protein-Water Interactions

The structures of proteins exhibit secondary elements composed of helices and loops. Comparison of several water-only hydrophobicity scales with the functionalities of two repeat proteins shows that these secondary elements possess water-induced medium-range order that is sometimes similar, but can also be complementary, to structural order. Study of these hitherto "phantom" order parameters promises far-reaching incremental improvements in the theory of protein dynamics. A by-product of the theory is an independent evaluation of the reliability of different hydrophobicity scales.

cond-mat.soft↗

arXiv2008

Reversibility, Water-Mediated Switching, and Directed Cell Dynamics

Reversible switching of the complex network dynamics of proteins is mimicked in selected network glasses and compacted small carbohydrate molecules. Protein transitions occur on long time scales ~ us -ms, evocative of the exponentially large viscosities found in glass-forming supercooled liquids just above the glass transition; in searching for mechanisms for reversibly slowed "geared activation", Kauzmann was led from proteins to glasses. I show here that selected network glasses and small carbohydrate molecules can be used to model such transitions, and elucidate in particular some universal aspects of tandem repeats. The human ankyrin tandem repeat D34, with a superhelical "coiled spring" structure which has 426 residues, folds reversibly and plastically. Such molecules are too large for present transition-state numerical simulations, currently limited to ~ 100 residues solvated by ~ 3000 water molecules for times ~ ns. The transition states of D34 exhibit a surprisingly simple collective ("geared") pattern when studied by fluorescence near its center, in samples modified mutageneously along its 12 helical repeats. One can understand this "plastic" pattern by taking advantage of a symmetric 45-atom carbohydrate molecular bridge to "cross over" from proteins to inorganic network glasses. There one easily identifies gears, and can show that the collective pattern is the signature of nonlocal, water-mediated [hydro(phobic/philic)] switching. Details of the transition patterns emerge from analyzing the amino acid alpha helical repeat sequences with water-only hydrophobicity scales. Freezing and melting of monolayer water films at physiological temperatures can enable ankyrin repeats to direct cell dynamics in muscles, membranes and cytoskeletons.

cond-mat.soft↗

arXiv2008

Protein Sequence, Structure, Stability and Functionality

Protein-protein interactions (protein functionalities) are mediated by water, which compacts individual proteins and promotes close and temporarily stable large-area protein-protein interfaces. Proteins are peptide chains decorated by amino acids, and protein scientists have long described protein-water interactions in terms of qualitative amino acid hydrophobicity scales. Here we examine several recent scales and argue plausibly (in terms of self-organized criticality) that one of them should be regarded as an absolute scale (within the protein universe), analogous to the dielectric scale of bond ionicity in inorganic octet compounds. Applications to repeat proteins (containing upwards of 900 amino acids) are successful, far beyond reasonable expectations, in all cases studied so far. While some of the results are obvious and can be obtained from the ex vitro spatial structures alone, many are hidden from plain view, and can be called phantom relations. As a byproduct, the network theory explains the exceptional functionality of leucine in zippers, heptads, and repeat consensus sites.

cond-mat.soft↗

arXiv2006

Self-Organized Networks and Lattice Effects in High Temperature Superconductors III: Dopant Internal Structure

The self-organized dopant percolative filamentary model, entirely orbital in character (no fictive spins), predicted the existence and even the ~ 3 nm diameters of gap nanodomains (discovered by STM) that amazed almost all theorists in this field. Here it explores the self-consistent and self-limiting coupling between dopant sites and gap character. It explains precursive magnetic effects and shows that they are caused by dopant ordering into loops at an onset temperature of order 2Tc. The ordered coupling of these loops by filamentary connectors is reflected by Debye-Waller factors, and it apparently leads to HTSC. The model also resolves the mystery of the vanishing isotope effect, and it explains the origin of the high-energy "waterfall" recently discovered by ARPES, as well as some overlooked infrared anomalies.

cond-mat.supr-con↗

arXiv2006

Self-Organized Networks and Lattice Effects in High Temperature Superconductors II: Fermi Arc Anomalies

The self-organized dopant percolative filamentary model, entirely orbital in character (no fictive spins), explains the evolution with doping of Fermi arcs observed by ARPES, including the previously unexplained abrupt transitions in quasiparticle strength observed near optimal doping in cuprate high temperature superconductors. Similarly abrupt transitions are also observed in time-resolved picosecond relaxation spectroscopy at 1.5 eV, and these are explained as well, using no new assumptions and no adjustable parameters.

cond-mat.supr-con↗

arXiv2006

Self-Organized Networks and Lattice Effects in High Temperature Superconductors I: Lattice Softening

The self-organized dopant percolative filamentary model, entirely orbital in character (no fictive spins), explains chemical trends in superconductive transition temperatures Tc, assuming that Cooper pairs are formed near dopants because attractive electron-phonon interactions outweigh repulsive Coulomb interactions. According to rules previously used successfully for network glasses, the host networks are marginally stable mechanically. The high Tc's are caused by softening of the host network, enormously enhanced by large electron-phonon interactions at interlayer dopants for states near the Fermi energy. Background (in)homogeneities (pseudogap regions) produce novel percolative features in phase diagrams.

cond-mat.supr-con↗

arXiv2006

Onset of rigidty in glasses: from random to self-organized networks

We review in this paper the signatures of a new elastic phase that is found in glasses with selected compositions. It is shown that in contrast with random networks, where rigidity percolates at a single threshold, networks that are able to self-organize to avoid stress will remain in an almost stress- free state during a compositional interval, an intermediate phase, that is bounded by a flexible phase and a stressed rigid phase. We report the experimental signatures and describe the theoretical efforts that have been accomplished to characterize the intermediate phase. We illustrate one of the methods used in more detail with the example of Group III chalcogenides and finally suggest further possible experimental signatures of self-organization.

cond-mat.mtrl-sci↗

arXiv2006

Strong Disorder and High Temperature Superconductivity

ARPES and wide area, high resolution STM studies of a micaceous cuprate high temperature superconductor have shown strong nanoscale gap disorder, but the question of whether this disorder is intrinsic and necessary for HTSC, or merely incidental to either this material, or even only its surface, appears to be an open one. We present the case that it is merely incidental, and then review the evidence that strong disorder is actually an essential factor in generating this unprecedented phenomenon.

cond-mat.dis-nn↗

arXiv2006

Microscopic Reversibility, Space-Filling, and Internal Stress in Strong Glasses

The axiomatic theory of ideally glassy networks, which has proved effective in describing phase diagrams and many properties of chalcogenide, oxide, and even molecular glasses, is here broadened to describe both geometrical properties, such as the first sharp diffraction peak, and kinetic properties, such as the nonreversible enthalpy of the glass transition, as measured by modulated differential scanning calorimetry. The discussion shows why the latter is such an effective tool for identifying strong glasses.

cond-mat.dis-nn↗