David Pines – författare

Evolution of self-replicating macromolecules through natural selection is a dynamically ordered process. Two concepts are introduced to describe the physical regularity of macromolecular evolution: sequence space and quasi-species. Natural selection means localization of a mutant distribution in sequence space. This localized distribution, called the quasi-species, is centered around a master sequence (or a degenerate set), that the biologist would call the wild-type. The self-ordering of such a system is an essential consequence of its formation through self-reproduction of its macromolecular consti tuents, a process that in the dynamical equations expresses itself by positive diagonal coefficients called selective values. The theory describes how population numbers of wild type and mutants are related to the distribution of selective values, that is to say, how value topography maps into population topography. For selectively (nearly) neutral mutants appearing in the quasi- species distribution, population numbers are greatly enhanced as compared to those of disadvantageous mutants, even more so in continuous domains of such selectively valuable mutants. As a consequence, mutants far distant from the wild type may occur because they are produced with the help of highly populated, less distant precursors. Since values are cohesively distributed, like mountains on earth, and since their positions are multiply connected in the high-dimensional sequence space, the overpopulation of (nearly) neural mutants provides guidance for the evolutionary process. Localization in sequence space, subject to a threshold in the fidelity of reproduction, is steadily challenged until an optimal state is reached. The model has been designed according to experimentally determined properties of self-replicating molecules. The conclusions reached from the theoretical models can be used to construct machines that provide optimal conditions for the evolution of functional macromolecules.

This book is concerned with a single group of quantum liquids, normal Fermi liqztids, discussing the nature of elementary excitations, the central concept of response functions. It is intended as a text for a graduate course in quantum statistical mechanics or low temperature theory.

This book provides a unified account of the theory of quantum liquid and discusses the mathematical theory of linear response and correlations. It is helpful for experimental physicists working in the fields of low-temperature or solid-state physics.

This book is a very early systematic treatment of the application of the field-theoretical methods developed after the Second World War to the quantum mechanical many-body problem at finite temperature. It describes various techniques that remain basic tools of modern condensed matter physicists.

A classic overview of the science of complexity from the prestigious Santa Fe Institute. There has been a remarkable growth in collaborative academic research focused on complexity in recent years. One of the greatest challenges is to discover which features are essential and which shared by all the seemingly disparate systems that are described as complex. This book describes current views on this subject held by various eminent scholars associated with the Santa Fe Institute, including Murray Gell-Mann, Brian Arthur, Stuart Kauffman, John Holland, and Kenneth Arrow. }The terms complexity, complex adaptive systems, and sciences of complexity are found often in recent scientific literature, reflecting the remarkable growth in collaborative academic research focused on complexity from the origin and dynamics of organisms to the largest social and political organizations. One of the great challenges in this field of research is to discover which features are essential and shared by all of the seemingly disparate systems that are described as complex. Is there sufficient synthesis to suggest the possibility of an overarching science of complexity?This report describes current views on this subject held by various eminent scholars associated with the Santa Fe Institute.The physical sciences have traditionally been concerned with simple systems whose dynamics can be described in mathematical terms with precision and certainty. In contrast, the biological and social sciences are inevitably concerned with self-organized or social complex systems whose detailed behaviors appear to be unpredictable. The two categories differ greatly in size and diversity, prompting the late mathematician Stanislaus Ulam to remark that research on complex systems might be compared to the study of non-elephants. Nevertheless, certain integrative themes have begun to emerge.Rising activity in this field of research runs completely counter to the trend toward increasing fragmentation and specialization in the sciences. It has stimulated a resurgence of interest in a broad synthesis involving mathematics, computational science, physics, chemistry, biology, neuroscience, and the social sciences.The growth of effort in this very extended field has been greatly stimulated by the development of new computational tools that are capable of dealing with vast, interrelated databases. Many of the participants in complexity research feel that it is now time to reintegrate the fragmented interests of much of the academic community. The reader is encouraged to consider whether such views are sparking a historic renaissance of scholarship or represent a passing scientific diversion. }

This text continues to fill the need to communicate the present view of a solid as a system of interacting particles which, under suitable circumstances, behaves like a collection of nearly independent elementary excitations. In addition to introducing basic concepts, the author frequently refers to experimental data. Usually, both the basic theory and the applications discussed deal with the behavior of '`'simple' metals, rather than the '`'complicated' metals, such as the transition metals and the rare earths. Problems have been included for most of the chapters.

This book provides a unified account of the theory of quantum liquid and discusses the mathematical theory of linear response and correlations. It is helpful for experimental physicists working in the fields of low-temperature or solid-state physics.

This book is concerned with a single group of quantum liquids, normal Fermi liqztids, discussing the nature of elementary excitations, the central concept of response functions. It is intended as a text for a graduate course in quantum statistical mechanics or low temperature theory.

The Santa Fe Institute, as key element in its founding activities, sponsored two workshops on 'Emerging Syntheses in Science.' There was unanimous agreement among the participants that Professor Gell-Mann's keynote address and the ensuing talks were of such high quality and general interest that it would be highly desirable to publish these for bro

This volume, first published in 1998, presents developments in urban geography, club theory and local public finance, and international trade which contribute to the explanation of the modern opposing trends of integration and segregation. Part I explores the role of transportation costs, crowding, and preferences for a large variety of goods in shaping the main features of urban geography. Part II contains four contributions on fundamental issues associated with the provision of collective goods (club goods and local public goods) using a game-theoretic approach. Part III investigates features of the production, pricing, and consumption of congested public goods. The articles discuss the financing of transportation infrastructure (a special case of a congested public facility) in an intertemporal framework, the efficiency of monopolistic provision of congested public goods, the 'musical-suburbs' problem, and the influence of cessation forces on federations. Part IV covers key tax issues arising in a world where economic borders are gradually being removed.

This volume, first published in 1998, presents developments in urban geography, club theory and local public finance, and international trade which contribute to the explanation of the modern opposing trends of integration and segregation. Part I explores the role of transportation costs, crowding, and preferences for a large variety of goods in shaping the main features of urban geography. Part II contains four contributions on fundamental issues associated with the provision of collective goods (club goods and local public goods) using a game-theoretic approach. Part III investigates features of the production, pricing, and consumption of congested public goods. The articles discuss the financing of transportation infrastructure (a special case of a congested public facility) in an intertemporal framework, the efficiency of monopolistic provision of congested public goods, the 'musical-suburbs' problem, and the influence of cessation forces on federations. Part IV covers key tax issues arising in a world where economic borders are gradually being removed.

This text continues to fill the need to communicate the present view of a solid as a system of interacting particles which, under suitable circumstances, behaves like a collection of nearly independent elementary excitations. In addition to introducing basic concepts, the author frequently refers to experimental data. Usually, both the basic theory and the applications discussed deal with the behavior of '`'simple' metals, rather than the '`'complicated' metals, such as the transition metals and the rare earths. Problems have been included for most of the chapters.

Some twenty-three years after the discovery of pulsars and their identification as rotating neutron stars, neutron star physics may be regarded as comingofage. Pul­ sars and accreting neutron stars have now been studied at every wavelength, from the initial radio observations, through optical, X-, and "{-ray, up to the very recent observations in the TeV region, while theorists have studied in some detail relevant physical processes both outside and inside neutron stars. As a result, comparisonof theory with observation provides a test ofour theoretical ideas in fields as diverse as neutron and nuclear matter, superfluidity and superconductivity, the acceleration of high energy particles, and the generation and maintenance of intense magnetic fields. For example, through observations of glitches and post glitch behavior of pulsars, it has become possible to establish the presence ofsuperfluid neutron mat­ ter in the inner crust of neutron stars, and to determine some of its properties, while neutron stars in compact binary systems offer one ofthe most efficient energy generation mechanisms known. It is in fact the interactive interpretation of these ,diverse pieces of information that can lead to major advances in our understanding of the physics of these exotic objects, and justifies the characterization of neutron stars as hadron physics laboratories.

Urban economic theory has been one of the most active areas of urban and regional economic research. Static general equilibrium theory is at the core of modern microeconomics, and the topic of this book - the static allocation of resources within a city and between cities - is at the core of urban economic theory. This volume attempts to reflect the state of the field. Part I provides a rigorous presentation of several variants of the monocentric (city) model - as the centrepiece of urban economic theory - treating equilibrium, optimum, and comparative statistics. Part II explores less familiar and even some uncharted territory. The monocentric model looks at a single city in isolation, taking as given a central business district surrounded by residences. Part II, in contrast, makes the intra-urban location of residential and non-residential activity the outcome of the fundamental trade-off between the propensity to interact and the aversion to crowding; the resulting pattern of agglomeration may be polycentric.Part II also develops models of an urbanized economy with trade between specialized cities and examines how the market-determined size distribution of cities differs from the optimum. This book launches a new series, "Advances in Urban and Regional Economics". The series aims to provide an outlet for longer scholarly works dealing with topics in urban and regional economics.

Over the past thirty years, urban economic theory has been one of the most active areas of urban and regional economic research. Just as static general equilibrium theory is at the core of modern microeconomics, so is the topic of this book - the static allocation of resources within a city and between cities - at the core of urban economic theory. An Essay on Urban Economic Theory well reflects the state of the field. Part I provides an elegant, coherent, and rigorous presentation of several variants of the monocentric (city) model - as the centerpiece of urban economic theory - treating equilibrium, optimum, and comparative statistics. Part II explores less familiar and even some uncharted territory. The monocentric model looks at a single city in isolation, taking as given a central business district surrounded by residences. Part II, in contrast, makes the intra-urban location of residential and non-residential activity the outcome of the fundamental tradeoff between the propensity to interact and the aversion to crowding; the resulting pattern of agglomeration may be polycentric. Part II also develops models of an urbanized economy with trade between specialized cities and examines how the market-determined size distribution of cities differs from the optimum. This book launches a new series, Advances in Urban and Regional Economics. The series aims to provide an outlet for longer scholarly works dealing with topics in urban and regional economics.