Hopfield, John J.
Overview
Works:  17 works in 19 publications in 1 language and 25 library holdings 

Genres:  Academic theses Guidebooks Conference papers and proceedings 
Roles:  Thesis advisor, Author 
Classifications:  QC176.8.E4, 620.00452 
Publication Timeline
.
Most widely held works by
John J Hopfield
Collective computation in neuronlike circuits by David W Tank(
)
1 edition published in 1987 in English and held by 3 WorldCat member libraries worldwide
1 edition published in 1987 in English and held by 3 WorldCat member libraries worldwide
Neural networks, pattern recognition, and fingerprint hallucination by
Eric Mjolsness(
)
2 editions published in 1986 in English and held by 2 WorldCat member libraries worldwide
2 editions published in 1986 in English and held by 2 WorldCat member libraries worldwide
Dynamic properties of neural networks by
Dawei Dong(
Book
)
1 edition published in 1991 in English and held by 2 WorldCat member libraries worldwide
1 edition published in 1991 in English and held by 2 WorldCat member libraries worldwide
The theory of long distance electron transfer reactions by David Nathan Beratan(
)
2 editions published in 1986 in English and held by 2 WorldCat member libraries worldwide
The rate of electron transport between distant sites was studied. The rate depends crucially on the chemical details of the donor, acceptor, and surrounding medium. These reactions involve electron tunneling through the intervening medium and are, therefore, profoundly influenced by the geometry and energetics of the intervening molecules. The dependence of rate on distance was considered for several rigid donoracceptor "linkers" of experimental importance. Interpretation of existing experiments and predictions for new experiments were made. The electronic and nuclear motion in molecules is correlated. A BornOppenheimer separation is usually employed in quantum chemistry to separate this motion. Long distance electron transfer rate calculations require the total donor wave function when the electron is very far from its binding nuclei. The BornOppenheimer wave functions at large electronic distance are shown to be qualitatively wrong. A model which correctly treats the coupling was proposed. The distance and energy dependence of the electron transfer rate was determined for such a model
2 editions published in 1986 in English and held by 2 WorldCat member libraries worldwide
The rate of electron transport between distant sites was studied. The rate depends crucially on the chemical details of the donor, acceptor, and surrounding medium. These reactions involve electron tunneling through the intervening medium and are, therefore, profoundly influenced by the geometry and energetics of the intervening molecules. The dependence of rate on distance was considered for several rigid donoracceptor "linkers" of experimental importance. Interpretation of existing experiments and predictions for new experiments were made. The electronic and nuclear motion in molecules is correlated. A BornOppenheimer separation is usually employed in quantum chemistry to separate this motion. Long distance electron transfer rate calculations require the total donor wave function when the electron is very far from its binding nuclei. The BornOppenheimer wave functions at large electronic distance are shown to be qualitatively wrong. A model which correctly treats the coupling was proposed. The distance and energy dependence of the electron transfer rate was determined for such a model
Data driven production models for speech processing by Sam T Roweis(
Book
)
1 edition published in 1999 in English and held by 2 WorldCat member libraries worldwide
1 edition published in 1999 in English and held by 2 WorldCat member libraries worldwide
How do we think so fast? by
John J Hopfield(
Visual
)
1 edition published in 2001 in English and held by 2 WorldCat member libraries worldwide
Prof. John J. Hopfield, Princeton University. What is the source of the great effectiveness of neurobiology, which allows a brain to quickly accomplish tasks like recognize a particular person in a natural environment? When the physics of the devices in a computer can be explicitly used in an algorithm, computational hardware becomes unusually effective. Evolution permits neurobiology to exploit this. Prof. Hopfield illustrates a powerful connection between computational task and neurobiological hardware, in which an emergent property of collective synchronization of the events at individual neurons signals the answer to a difficult auditory task
1 edition published in 2001 in English and held by 2 WorldCat member libraries worldwide
Prof. John J. Hopfield, Princeton University. What is the source of the great effectiveness of neurobiology, which allows a brain to quickly accomplish tasks like recognize a particular person in a natural environment? When the physics of the devices in a computer can be explicitly used in an algorithm, computational hardware becomes unusually effective. Evolution permits neurobiology to exploit this. Prof. Hopfield illustrates a powerful connection between computational task and neurobiological hardware, in which an emergent property of collective synchronization of the events at individual neurons signals the answer to a difficult auditory task
Analysis and modeling of spike train correlations in the lateral geniculate nucleus by
Carlos Brody(
Book
)
1 edition published in 1998 in English and held by 2 WorldCat member libraries worldwide
1 edition published in 1998 in English and held by 2 WorldCat member libraries worldwide
Research in Statistical Mechanics and Solid State Physics(
Book
)
1 edition published in 1975 in English and held by 1 WorldCat member library worldwide
1 edition published in 1975 in English and held by 1 WorldCat member library worldwide
EffectiveImpurity Model of Optical Absorption Edges(
Book
)
1 edition published in 1972 in English and held by 1 WorldCat member library worldwide
A simple model of an amorphous or disordered semiconductor is presented in which the disorder is approximated by a distribution of effective impurities. In this model the disorder potential in a given region of the semiconductor is characterized by an effective charge, and the optical absorption in that region is calculated. The total absorption is then a statistical average (over effective charge distributions) of the absorption in the presence of a single effectiveimpurity. (Author)
1 edition published in 1972 in English and held by 1 WorldCat member library worldwide
A simple model of an amorphous or disordered semiconductor is presented in which the disorder is approximated by a distribution of effective impurities. In this model the disorder potential in a given region of the semiconductor is characterized by an effective charge, and the optical absorption in that region is calculated. The total absorption is then a statistical average (over effective charge distributions) of the absorption in the presence of a single effectiveimpurity. (Author)
Dynamical simulation and control of articulated limbs by Marcus Quintana Mitchell(
Book
)
1 edition published in 2009 in English and held by 1 WorldCat member library worldwide
1 edition published in 2009 in English and held by 1 WorldCat member library worldwide
New aspects of the theory of electron transfer reaction dynamics by J. N Onuchic(
Book
)
1 edition published in 1987 in English and held by 1 WorldCat member library worldwide
This thesis deals basically with some new aspects of the electron transfer theory. It is divided into four parts: (1) Chapter I gives an introduction to the electron transfer problem; (2) Chapter II addresses the subject of hoe nuclear dynamics influences the electron transfer rate; (3) Chapter III explains how to calculate electron transfer matrix elements for nonadiabatic electron transfer systems, in particular protein systems; and (4) Chapter IV discusses some preliminary ideas about new problems I intend to work on the future. In Chapter II the following dynamical problems are addressed. For the case of one overdamped reaction coordinate, the problem of adiabaticity and nonadiabaticity is considered in detaisl. for an underdamped reaction coordinate, a preliminary discussion is give. All this formalism is developed using a density matrix formalism and path integral techniques. One of the advantages of using this formalism is that, by analyzing the spectral density, we can connect our microscopic Hamiltonian with macroscopic quantities. It also gives us a natural way of including friction in the problem. We also determine when the Hopfield semiclassical of the Jortner "quantum" models are good approximations to the "complete" Hamiltonian. In the limit that the reaction coordinates are "classical", we discuss how we can obtain the FokkerPlanck equation associated with de Hamiltonian. By adding more than one reaction coordinate to the problem (normally two), several other problems are studied. The separation of "fast" quantum modes from "slow" semiclassical modes, where the fast modes basically renormalize the electronic matrix element and the driving force of the electron transfer reaction, is discussed. Problems such as exponential and nonexponential decay in time of the donor survival probability,a nd the validity of the BornOppenheimer and Condon approximations are also carefully addressed. This chapter is concluded with a calculation of the reaction rate in the inverted region for the extreme adiabatic limit. In Chapter III we discuss calculations of electronic matrix elements, which are essential for the calculation of nonadiabatic rates. It starts with a discussion of why, through bond rather than through space, electron transfer is the important mechnism in model compounds. Also, it explains why tightbinding Hückel calculations are reasonable for evaluating these matrix elements, and why, through space and through bond, matrix element decays with distance have a different functional dependence on energy. Bridge effects due to diffeent hydrocarbon linkers are also calculated. This capter concludes with a model for the calculation of matrix elements in proteins. The model assumes that the important electron transfer "pathways" are composed of both, through bond and through space parts. Finally, we describe how medium (bridge) fluctuations may introduce a new form of temperature dependence by modulatin the matrix element. In Chapter IV we discuss some experimental results obtained for electron transfer in the porphyrinphenyl(bicyclo[2.2.2]octand)nquinone molecule, and we propose some new experiments that should help clarify our interpretation. It concludes with some preliminary discussions of how we can include entropy in the finite mode formalism described in Chapter II, and how we intend to use the formalism described in Chapter III in order to understand electron transfer in real protein systems
1 edition published in 1987 in English and held by 1 WorldCat member library worldwide
This thesis deals basically with some new aspects of the electron transfer theory. It is divided into four parts: (1) Chapter I gives an introduction to the electron transfer problem; (2) Chapter II addresses the subject of hoe nuclear dynamics influences the electron transfer rate; (3) Chapter III explains how to calculate electron transfer matrix elements for nonadiabatic electron transfer systems, in particular protein systems; and (4) Chapter IV discusses some preliminary ideas about new problems I intend to work on the future. In Chapter II the following dynamical problems are addressed. For the case of one overdamped reaction coordinate, the problem of adiabaticity and nonadiabaticity is considered in detaisl. for an underdamped reaction coordinate, a preliminary discussion is give. All this formalism is developed using a density matrix formalism and path integral techniques. One of the advantages of using this formalism is that, by analyzing the spectral density, we can connect our microscopic Hamiltonian with macroscopic quantities. It also gives us a natural way of including friction in the problem. We also determine when the Hopfield semiclassical of the Jortner "quantum" models are good approximations to the "complete" Hamiltonian. In the limit that the reaction coordinates are "classical", we discuss how we can obtain the FokkerPlanck equation associated with de Hamiltonian. By adding more than one reaction coordinate to the problem (normally two), several other problems are studied. The separation of "fast" quantum modes from "slow" semiclassical modes, where the fast modes basically renormalize the electronic matrix element and the driving force of the electron transfer reaction, is discussed. Problems such as exponential and nonexponential decay in time of the donor survival probability,a nd the validity of the BornOppenheimer and Condon approximations are also carefully addressed. This chapter is concluded with a calculation of the reaction rate in the inverted region for the extreme adiabatic limit. In Chapter III we discuss calculations of electronic matrix elements, which are essential for the calculation of nonadiabatic rates. It starts with a discussion of why, through bond rather than through space, electron transfer is the important mechnism in model compounds. Also, it explains why tightbinding Hückel calculations are reasonable for evaluating these matrix elements, and why, through space and through bond, matrix element decays with distance have a different functional dependence on energy. Bridge effects due to diffeent hydrocarbon linkers are also calculated. This capter concludes with a model for the calculation of matrix elements in proteins. The model assumes that the important electron transfer "pathways" are composed of both, through bond and through space parts. Finally, we describe how medium (bridge) fluctuations may introduce a new form of temperature dependence by modulatin the matrix element. In Chapter IV we discuss some experimental results obtained for electron transfer in the porphyrinphenyl(bicyclo[2.2.2]octand)nquinone molecule, and we propose some new experiments that should help clarify our interpretation. It concludes with some preliminary discussions of how we can include entropy in the finite mode formalism described in Chapter II, and how we intend to use the formalism described in Chapter III in order to understand electron transfer in real protein systems
Bayesian methods for adaptive models by
David J. C MacKay(
Book
)
1 edition published in 1992 in English and held by 1 WorldCat member library worldwide
The bayesian framework for model comparison and regularisation is demonstrated by studying interpolation and classification problems modelled with both linear and nonlinear models, quantitatively embodying "Occam's razor". The concepts and methods described are quite general and will be applicable to other data modelling problems whether they involve pregression, classification or density estimation
1 edition published in 1992 in English and held by 1 WorldCat member library worldwide
The bayesian framework for model comparison and regularisation is demonstrated by studying interpolation and classification problems modelled with both linear and nonlinear models, quantitatively embodying "Occam's razor". The concepts and methods described are quite general and will be applicable to other data modelling problems whether they involve pregression, classification or density estimation
Experiments in very largescale analog computation by Douglas A Kerns(
Book
)
1 edition published in 1993 in English and held by 1 WorldCat member library worldwide
1 edition published in 1993 in English and held by 1 WorldCat member library worldwide
Analog VLSI supervised learning system by
Ron Benson(
Book
)
1 edition published in 1994 in English and held by 1 WorldCat member library worldwide
1 edition published in 1994 in English and held by 1 WorldCat member library worldwide
Algorithmic selfassembly of DNA by
Erik Winfree(
Book
)
1 edition published in 1998 in English and held by 1 WorldCat member library worldwide
1 edition published in 1998 in English and held by 1 WorldCat member library worldwide
Models of visual feature detection and spike coding in the nervous system by Thomas Mark Annau(
Book
)
1 edition published in 1996 in English and held by 1 WorldCat member library worldwide
1 edition published in 1996 in English and held by 1 WorldCat member library worldwide
The ultraviolet spectrum of the sun from V2 rockets by
John J Hopfield(
Book
)
1 edition published in 1947 in English and held by 1 WorldCat member library worldwide
1 edition published in 1947 in English and held by 1 WorldCat member library worldwide
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Related Identities
 California Institute of Technology Division of Engineering and Applied Science
 California Institute of Technology Division of Physics, Mathematics and Astronomy
 Tank, David W. Author
 AbuMostafa, Yaser S. 1957 Thesis advisor
 California Institute of Technology Division of Biology
 California Institute of Technology Division of Chemistry and Chemical Engineering
 Brody, Carlos Author
 Perona, Pietro Thesis advisor
 Roweis, Sam T. Author
 University of California, Berkeley Department of Physics
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Associated Subjects
Alternative Names
Džons Džozefs Hopfīlds
John Hopfield USamerikanischer Physiker und Biologe
John Joseph Hopfield physicien amricain
Джон Хопфілд
Хопфилд, Джон
ג'ון ג'וזף הופפילד
جان هاپفیلد
জন জোসেফ হোপফিল্ড
ジョン・ホップフィールド
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