Physics category

From complexity to life: on the emergence of life and meaning

This book brings together an impressive group of leading scholars in the sciences of complexity, and a few workers on the interface of science and religion, to explore the wider implications of complexity studies. It includes an introduction to complexity studies and explores the concept of information in physics and biology and various philosophical and religious perspectives. Chapter authors include Paul Davies, Greg Chaitin, Charles Bennett, Werner Loewenstein, Paul Dembski, Ian Stewart, Stuart Kauffman, Harold Morowitz, Arthur Peacocke, and Niels H. Gregersen.

published on 20-02-2020 - 54 views
Brains and Realities

Modern physics clearly points out that we live in a universe where space and time may be stubborn illusions. The intriguing question is: How did mystics who lived more than 2,000 years ago come to the same conclusions without the aid of scientific instruments or advanced mathematics? Is there really a timeless and spaceless sphere that we can access here and now by merely altering processes in the human brain? This book aims to answer this question. Also by Jay Alfred: Between the Moon and the Earth and Our Invisible Bodies

published on 07-02-2020 - 70 views
The Problems of Philosophy

Bertrand Russell attempts to create a brief and accessible guide to the problems of philosophy. Focusing on problems he believes will provoke positive and constructive discussion, Russell concentrates on knowledge rather than metaphysics. A lively and still one of the best introductions to philosophy, this book pays off both a closer reading for students and specialists, and a casual reading for the general public.

published on 30-01-2020 - 96 views
Frequently Asked Questions In Quantitative Finance

Paul Wilmott writes, "Quantitative finance is the most fascinating and rewarding real-world application of mathematics. It is fascinating because of the speed at which the subject develops, the new products and the new models which we have to understand. And it is rewarding because anyone can make a fundamental breakthrough. "Having worked in this field for many years, I have come to appreciate the importance of getting the right balance between mathematics and intuition. Too little maths and you won't be able to make much progress, too much maths and you'll be held back by technicalities. I imagine, but expect I will never know for certain, that getting the right level of maths is like having the right equipment to climb Mount Everest; too little and you won't make the first base camp, too much and you'll collapse in a heap before the top. "Whenever I write about or teach this subject I also aim to get the right mix of theory and practice. Finance is not a hard science like physics, so you have to accept the limitations of the models. But nor is it a very soft science, so without those models you would be at a disadvantage compared with those better equipped. I believe this adds to the fascination of the subject. "This FAQs book looks at some of the most important aspects of financial engineering, and considers them from both theoretical and practical points of view. I hope that you will see that finance is just as much fun in practice as in theory, and if you are reading this book to help you with your job interviews, good luck! Let me know how you get on!"

published on 30-01-2020 - 104 views
Linear Momentum and Collisions.pdf

consider what happens when a golf ball is struck by a club. The ball is given a very large initial velocity as a result of the collision; consequently, it is able to travel more than 100 m through the air. The ball experiences a large acceleration. Furthermore, because the ball experiences this acceleration over a very short time interval, the average force exerted on it during the collision is very great. According to Newton’s third law, the ball exerts on the club a reaction force that is equal in magnitude to and opposite in direction to the force exerted by the club on the ball. This reaction force causes the club to accelerate. Because the club is much more massive than the ball, however, the acceleration of the club is much less than the acceleration of the ball

published on 29-01-2020 - 82 views
The Laws of Motion.pdf

What might cause one particle to remain at rest and another particle to accelerate? In this chapter, we investigate what causes changes in motion. The two main factors we need to consider are the forces acting on an object and the mass of the object.

published on 29-01-2020 - 113 views
Motion in One Dimension.pdf

As a first step in studying classical mechanics, we describe motion in terms of space and time while ignoring the agents that caused that motion. This portion of classical mechanics is called kinematics.(The word kinematicshas the same root as cinema.Can you see why?) In this chapter we consider only motion in one dimension. We first define displacement, velocity, and acceleration. Then, using these concepts, we study the motion of objects traveling in one dimension with a constant acceleration.

published on 29-01-2020 - 68 views
Physics and Measurement.pdf

Like all other sciences, physics is based on experimental observations and quantitative measurements. The main objective of physics is to find the limited number of fundamental laws that govern natural phenomena and to use them to develop theories that can predict the results of future experiments. The fundamental laws used in developing theories are expressed in the language of mathematics, the tool that provides a bridge between theory and experiment.

published on 29-01-2020 - 101 views
Electronique Analogique

ce livre parle des transistor: les transistor bipolaire, de la polarisation, les différents états du transistor, de son schéma équivalent et des Montage fondamentaux en régime de petits signaux.

published on 24-01-2020 - 73 views
The quantum mechanics solver: how to apply quantum theory to modern physics

The Quantum Mechanics Solver uniquely illustrates the application of quantum mechanical concepts to various fields of modern physics. It aims at encouraging the reader to apply quantum mechanics to research problems in fields such as molecular physics, condensed matter physics or laser physics. Advanced undergraduates and graduate students will find a rich and challenging source of material for further exploration. This book consists of a series of problems concerning present-day experimental or theoretical questions on quantum mechanics. All of these problems are based on actual physical examples, even if sometimes the mathematical structure of the models under consideration is simplified intentionally in order to get hold of the physics more rapidly. The new edition features new themes, such as the progress in measuring neutrino oscillations, quantum boxes, the quantum thermometer etc. Secondly, it includes a brief summary on the basics of quantum mechanics and the formalism we use. Finally, the problems under three main themes: Elementary Particles, Nuclei and Atoms; Quantum Entanglement and Measurement; and Complex Systems.

published on 20-01-2020 - 148 views
Mistress of the Web

IT ALL BEGINS IN THIS STUNNING FIRST NOVEL! Born in rage, a killer before she left the amniotic sac, the Lady Desdemona is a genetically enhanced vampire, a death goddess with three thousand years of bloody history tucked under her belt - and no signs of slowing down. In the festering city of Golgotha Falls high technology meshes uncomfortably with ancient ritual - here there are doorways that exist in the very fabric of space and time, software programmes that can overwrite a man's personality, monsters born on the dark side of physics and demons that bypass the laws of physics altogether. Golgotha Falls is a city that caters to every unholy fetish and every sordid desire, a technological wonderland with a dark, toxic underbelly.

published on 18-01-2020 - 182 views
Murder on the Einstein Express and Other Stories

This collection of stories touches upon many genres: Normed Trek is a clever and witty Alice-in-Wonderland-type narrative set in the realm of mathematical analysis, The Cantor Trilogy is a dystopia about the consequences of relying upon computer-based mathematical proofs, In Search of Future Time bears the flavor of Tales from Arabian Nights set in the future, and – last but not least - Murder on the Einstein Express is a short, non-technical primer on probabilities and modern classical physics, disguised as a detective story. Written primarily for an audience with some background or a strong interest in mathematics, physics and computer science (in particular artificial intelligence), these stories explore the boundaries between science and fiction in a refreshingly unconventional fashion. In the Afterthoughts the author provides some further insights and annotations

published on 06-01-2020 - 189 views
Against the Gods: The Remarkable Story of Risk

A Business Week, New York Times Business, and USA Today Bestseller"Ambitious and readable . . . an engaging introduction to the oddsmakers, whom Bernstein regards as true humanists helping to release mankind from the choke holds of superstition and fatalism." -The New York Times"An extraordinarily entertaining and informative book." -The Wall Street Journal"A lively panoramic book . . . Against the Gods sets up an ambitious premise and then delivers on it." -Business Week"Deserves to be, and surely will be, widely read." -The Economist"[A] challenging book, one that may change forever the way people think about the world." -Worth"No one else could have written a book of such central importance with so much charm and excitement." -Robert Heilbroner author, The Worldly Philosophers"With his wonderful knowledge of the history and current manifestations of risk, Peter Bernstein brings us Against the Gods. Nothing like it will come out of the financial world this year or ever. I speak carefully: no one should miss it." -John Kenneth Galbraith Professor of Economics Emeritus, Harvard UniversityIn this unique exploration of the role of risk in our society, Peter Bernstein argues that the notion of bringing risk under control is one of the central ideas that distinguishes modern times from the distant past. Against the Gods chronicles the remarkable intellectual adventure that liberated humanity from oracles and soothsayers by means of the powerful tools of risk management that are available to us today."An extremely readable history of risk." -Barron's"Fascinating . . . this challenging volume will help you understand the uncertainties that every investor must face." -Money"A singular achievement." -Times Literary Supplement"There's a growing market for savants who can render the recondite intelligibly-witness Stephen Jay Gould (natural history), Oliver Sacks (disease), Richard Dawkins (heredity), James Gleick (physics), Paul Krugman (economics)-and Bernstein would mingle well in their company." -The Australian

published on 31-12-2019 - 141 views
Quantitative Analysis of Voids in Percolating Structures in Two-Dimensional N-Body Simulations

We present in this paper a quantitative method for defining void size in large-scale structure based on percolation threshold density. Beginning with two-dimensional gravitational clustering simulations smoothed to the threshold of nonlinearity, we perform percolation analysis to determine the large scale structure. The resulting objective definition of voids has a natural scaling property, is topologically interesting, and can be applied immediately to redshift surveys.

published on 04-12-2019 - 219 views
Quantitative Analysis of Voids in Percolating Structures in Two-Dimensional N-Body Simulations

We present in this paper a quantitative method for defining void size in large-scale structure based on percolation threshold density. Beginning with two-dimensional gravitational clustering simulations smoothed to the threshold of nonlinearity, we perform percolation analysis to determine the large scale structure. The resulting objective definition of voids has a natural scaling property, is topologically interesting, and can be applied immediately to redshift surveys.

published on 22-11-2019 - 238 views
The Gravitational Lens System B1422+231: Dark Matter, Superluminal Expansion and the Hubble Constant

A gravitational lens model of the radio quasar B1422+231 is presented which can account for the image arrangement and approximately for the relative magnifications. The locations of the principal lensing mass and a more distant secondary mass concentration were predicted and subsequently luminous galaxies were found at these locations. This argues against the existence of substantial numbers of “dark” galaxies. The model suggests that if the compact radio source is intrinsically superluminal then the observed component motions may be as large as ∼ 100 c with image B moving in the opposite direction to images A and C. The prospects for a measuring the Hubble constant from a model incorporating lens galaxy locations, compact radio source expansion speeds and radio time delays, if and when these are measured, are briefly assessed.

published on 22-11-2019 - 248 views
Graviton Mode Function in Inflationary Cosmology

We consider the production of gravitons in an inflationary cosmology by ap- proximating each epoch of change in the equation of state as sudden, from which a simple analytic graviton mode function has been derived. We use this mode func- tion to compute the graviton spectral energy density and the tensor-induced cosmic microwave background anisotropy.

published on 22-11-2019 - 216 views
Solar Model Uncertainties, MSW Analysis, and Future Solar Neutrino Experiments

Various theoretical uncertainties in the standard solar model and in the Mikheyev-Smirnov-Wolfenstein (MSW) analysis are discussed. It is shown that two methods of estimating the solar neutrino flux uncertainties are equivalent:

published on 22-11-2019 - 222 views
A Liouville String Approach to Microscopic Time and Cosmology

In the non-critical string framework that we have proposed recently, the time t is identified with a dynamical local renormalization group scale, the Liouville mode, and behaves as a statistical evolution parameter, flowing irreversibly from an infrared fixed point - which we conjecture to be a topological string phase - to an ultraviolet one - which corresponds to a static critical string vacuum. When applied to a toy two-dimensional model of space- time singularities, this formalism yields an apparent renormalization of the velocity of light, and a t-dependent form of the uncertainty relation for position and momentum of a test string. We speculate within this framework on a stringy alternative to conventional field-theoretical inflation, and the decay towards zero of the cosmological constant in a maximally-symmetric space.

published on 22-11-2019 - 220 views
A Cosmic String Specific Signature on the Cosmic Microwave Background

Using an analytical model for the string network we show that the kurtosis of cosmic microwave background (CMB) temperature gradi- ent maps is a good statistic to distinguish between the cosmic string model and inflationary models of structure formation.

published on 22-11-2019 - 237 views
A MORPHOLOGY{COSMOLOGY CONNECTION FOR X{RAY CLUSTERS

We employ N{body/3D gas dynamic simulations of the formation of galaxy clusters to determine whether cluster X{ray morphologies can be used as cosmological constraints. Con rming the analytic expectations of Richstone, Loeb, & Turner, we demonstrate that cluster evolution is sensitive to the cosmological model in which the clusters form. We further show that evolutionary di erences are echoed in the gross morphological features of the cluster X{ray emission.

published on 22-11-2019 - 221 views
Do gamma-ray bursts come from the Oort cloud?

We examine the possibility that gamma-ray bursts arise from sources in the Oort comet cloud, basing most of our arguments on accepted models for the formation and spatial distribution of the cloud

published on 22-11-2019 - 212 views
SOME STATISTICS FOR MEASURING LARGE-SCALE STRUCTURE

Good statistics for measuring large-scale structure in the Universe must be able to distinguish between different models of structure formation. In this paper, two and three dimensional “counts in cell” statistics and a new “discrete genus statis- tic” are applied to toy versions of several popular theories of structure formation: random phase cold dark matter model, cosmic string models, and global texture scenario. All three statistics appear quite promising in terms of differentiating between the models.

published on 22-11-2019 - 191 views
Gamma-Ray Bursts and Topology of the Universe

In this letter we propose a physical explanation for recently reported correla- tions between pairs of close and antipodal gamma-ray bursts from publicly avail- able BATSE catalogue. Our model is based on the cosmological scenario in which bursters are located at cosmological distances of order of 0.5–2 Gpc. Observed dis- tribution of gamma-ray bursts strongly suports this assumption. If so gamma-ray bursts may provide a very good probe for investigating the topological structure of the Universe. We notice that correlation between antipodal events may in fact indicate that we live in the so called Ellis’ small universe which has Friedman- Roberston-Walker metric structure and nontrivial topology.

published on 22-11-2019 - 221 views
ON THE LIMITATIONS OF NEUTRINO EMISSIVITY FORMULA OF IWAMOTO

The neutrino emissivity from two and three flavour quark matter is numerically cal- culated and compared with Iwamoto’s formula

published on 22-11-2019 - 207 views
POTENT AND MAX-FLOW ALGORITHMS

Although Potent purports to use only radial velocities in retrieving the potential ve- locity eld of galaxies, the derivation of transverse components is implicit in the smoothing procedures. Thus the possibility of using nonradial line integrals to derive the velocity eld arises. In the case of inhomogeneous distributions of galaxies, the optimal path for integration need not be radial, and can be obtained by using max- ow algorithms. In this paper we present the results of using Dijkstra's algorithm to obtain this optimal path and velocity eld.

published on 22-11-2019 - 214 views
BIAS IN VELOCITY FIELD RECOVERIES

We investigate the e ect of using di erent distance estimators on the recovery of the peculiar velocity eld of galaxies using Potent. An inappropriate choice of distance estimator will give rise to spurious ows. We discuss methods of minimising these biases and the levels of accuracy required of distance estimators to retrieve velocity elds to a given standard.

published on 22-11-2019 - 190 views
BAYESIAN ESTIMATES OF THE LARGE-SCALE VELOCITY FIELD IN REAL SPACE AND REDSHIFT SPACE

Methods for inferring the velocity eld from the peculiar velocity data are described and applied to old and newer data. Inhomogeneous Malmquist bias and ways to avoid it are discussed and utilized. We infer that these biases are probably important in interpreting the data.

published on 22-11-2019 - 208 views