bluuebunny/crossref_metadata_2025_split huggingface dataset:
Linear Response Theory
Authors: Bruus Henrik , Flensberg Karsten 
Published: November 2023

Abstract
Linear response theory is an extremely widely used concept in all branches of physics. It simply states that the response to a weak external perturbation is proportional to the perturbation, and therefore all one needs to understand is the proportionality constant. Below we derive the general formula for the linear response of a quantum system exerted by a perturbation. The physical question we ask is thus: given some external perturbation H′, what is the measured consequence for an observable quantity, A.
Equation of Motion Theory
Authors: Bruus Henrik , Flensberg Karsten 
Published: November 2023

Abstract
In the previous chapters, we saw how various physical observables can be expressed in terms of retarded Green’s functions. In many cases we need to calculate the time dependence of these functions. There are several ways of attacking this problem, one of which is the equation of motion technique. The basic idea of this method is to generate a series of coupled differential equations by differentiating the function at hand a number of times. If these equations close, the problem is in principle solvable; and if not, one needs to invoke physical arguments to truncate the set of equations in a reasonable fashion. For example, one can neglect certain correlations. We shall study examples of both situations in this chapter.
Green’s Functions and Phonons
Authors: Bruus Henrik , Flensberg Karsten 
Published: November 2023

Abstract
In this chapter, we develop and apply the Green’s function technique for free phonons and for the electron-phonon interaction. The point of departure is the second quantization formulation of the phonon problem presented in Chapter 3, in particular the bosonic phonon creation and annihilation operators b ℅ and b ℅ q introduced in Eqs. (3.10) and (3.22) and appearing in the jellium phonon Hamiltonian Eq. (3.4) and in the lattice phonon Hamiltonian Eq. (3.23).
Working With Eating Disorders
Authors: Turner Hannah 
Published: November 2023

Abstract
Although public awareness of eating disorders has increased considerably in recent years, many myths continue to surround these often severely debilitating disorders. Commonly misconstrued as ‘a diet that got out of hand ‘, the concept of an eating disorder can leave many feeling frustrated and perplexed, as they struggle to understand what appears to be an extraordinary state of obsession with eating, weight, and shape. However, beneath these worries there often lies a story of insecurity, anxiety, and fear. No one just wakes up one morning with an eating disorder—rather these are complex illnesses that develop over time and often as a result of multiple influences. The range of causative factors can be diverse and may include genetic and physical factors, personality traits, family dynamics, relationship problems, and adverse life events.
DNA topoisomerases
Authors: Bates Andrew D , Maxwell Anthony 
Published: November 2023

Abstract
Virtually every reaction that occurs in biological systems is catalysed by an enzyme. The interconversions of the different topological forms of DNA are no exceptions. The enzymes that catalyse these processes are known as DNA topoisomerases and constitute a widespread and fascinating group.
The first DNA topoisomerase was discovered by James Wang in 1971, the so-called ω protein from Escherichia coli (1). This enzyme, now called DNA topoisomerase I, was found to reduce the number of negative supercoils in bacteriophage λ DNA, as measured by changes in sedimentation coefficient (see Chapter 2, Section 2.2.2).
Cosmological spacetimes
Authors: Rindler Wolfgang 
Published: November 2023

Abstract
Introduction
Cosmology the inquiry into the largest-scale features of the universe has obviously excited Man’s curiosity since time immemorial. But in spite of the spectacular advances in astronomy since the days of Galileo and Kepler, cosmology remained more speculation than science until well into the twentieth century. Relevant observations were sparse, and so theories, however fanciful, could not be falsified. All this changed drastically with the advent of the giant telescopes early in the twentieth century, which suddenly brought a significant portion of the whole universe into view.
Clouds and aerosols
Authors: Taylor F W 
Published: November 2023

Abstract
Clouds are, in many ways, the most crucial part of the climate system, because they have a large effect on the energy balance of the atmosphere and surface, but are very variable and difficult to predict. On a warming Earth, would the amount of cloud cover increase? Would this result in an increase in the albedo of the planet, and would the cooling effect of this dominate the warming effect of adding further infrared opacity to the greenhouse effect, or vice versa? The answers to even these basic questions remain elusive. We will look at the role of clouds in the greenhouse effect and at attempts to model their contribution, in later chapters. Here we look at the basic physics of cloud formation and growth.
Radiative transfer
Authors: Taylor F W 
Published: November 2023

Abstract
We have already seen (Chapter 2) how the Sun delivers energy to the Earth as ultraviolet, visible, and near-infrared radiation, and how the Earth maintains an overall energy balance by re-emitting an equal amount of energy as long-wave, thermal infrared radiation. We calculated the total amounts of energy, and the wavelength of peak emission, from the Sun and the Earth, using the Stefan-Boltzmann law and the Wien displacement law respectively, and noted that both of these can be derived from Planck’s Radiation law, one of the most important formulae in modern Physics.
Earth’s energy budget: The ‘greenhouse’ effect
Authors: Taylor F W 
Published: November 2023

Abstract
The presence of the atmosphere raises the mean temperature of the surface of the Earth considerably over what it would be on an airless sphere with the same size, albedo, and distance from the Sun. Ignoring clouds for the moment, the air is largely transparent to the incoming solar flux, but mostly opaque to outgoing thermal infrared radiation. Thus the atmosphere forms a blanket that is colder on the outside than the inside. It presents an effective emitting temperature of about 255K towards outer space, representing equilibrium with the incoming solar power, while the temperature at the base of the atmosphere is around 33K higher.
Climate models and predictions
Authors: Taylor F W 
Published: November 2023

Abstract
Studies of climate and climate change, like those of virtually all problems involving complex coupled systems and a multitude of different processes, rely on models.120 Simple models provide useful insight into the physics involved, while complex models are necessary to obtain the greatest possible accuracy and to attempt to incorporate all of the feedback process. The simplest climate models are zero or one-dimensional energy balance models, like those introduced in Chapter 7. These have low computational costs and explicit formulations, so that the links between individual parameters or processes and the climate can be seen and their dependence evaluated.
Pendulums somewhat simple
Authors: Baker Gregory L , Blackburn James A 
Published: November 2023

Abstract
There are many kinds of pendulums. In this chapter, however, we intro duce a simplified model; the small amplitude, linearized pendulum. For the present, we ignore friction and in doing so obviate the need for energizing the pendulum through some forcing mechanism. Our initial discussion will therefore assume that the pendulum’s swing is relatively small; and this approximation allows us to linearize the equations and readily determine the motion through solution of simplified model equations. We begin with a little history.
Coupled pendulums
Authors: Baker Gregory L , Blackburn James A 
Published: November 2023

Abstract
It has been asked, ‘‘You know the sound of two hands clapping; what is the sound of one hand clapping?’’ Of course one hand does not clap. But there are answers to a related question, ‘‘You know the sound of two hands clapping; what is the sound of manyhands clapping?’’ Zolten Neda and his physicist colleagues in Romania have studied this question extensively in concert halls, theaters and opera houses (Neda et al. 2000). One of their conclusions is that at some point during the applause the aggregate noise from hand clapping will be periodic. Probably, most of us have experienced this phenomenon. (Being physicists, Neda and his colleagues also learn a lot of other things that the casual observer might miss.) This periodicityof the applause is an example of synchronization. Each component system— each pair of hands—acts in concert with all the other component systems to create a uniform pattern of clapping. But the applause may not neces sarilystayperiodic. If some audience members are more enthusiastic than others and break the pattern by clapping more frequently, then the applause can again become chaotic. Thus the degree of synchronization seems to depend upon the audience members being mutuallycoupled bya common level of enthusiasm. As an example, Neda et al. note, historically, that clapping at now-defunct communist party rallies typically stayed in the rhythmic state. One might conclude that the level of enthusiasm was fairly low at such gatherings. But let us discuss pendulums.
The quantum pendulum
Authors: Baker Gregory L , Blackburn James A 
Published: November 2023

Abstract
The classical pendulum has a long and rich history in physics. On the other hand, the history of the quantum pendulum can only stretch back as far as the appearance of quantum mechanics itself in 1925–1926. Yet within three years of that exciting time, a paper on the quantum pendulum appeared in Physical Review authored by one of the pioneers of atomic physics, Edward Condon (Condon 1928). Condon’s paper laid out the basic problem and the means to its solution. Contributions to the study of the quantum pendulum continue to be made even in recent times. See, for example, (Pradhan and Khare 1973; Aldrovandi and Ferreira 1980; Cook and Zaidins 1986; Baker et al. 2002). In this tale we describe some of the novel and surprising features of the pendulum when it is analyzed according to the rules of quantum physics.
Superconductivity and the pendulum
Authors: Baker Gregory L , Blackburn James A 
Published: November 2023

Abstract
There is a quite unexpected connection between the classical pendulum— chaotic or otherwise—and quantum mechanics when it functions on a macroscopic scale, as happens in superconductors. More specifically, the connection arises through something known as the Josephson effect. It turns out that there is an exact correspondence between the dynamics of Josephson devices and the dynamics of the classical pendulum. To uncover this curious relationship, we first review some essential ideas about superconductors and superconducting devices.
The Dutch physicist H. Kamerlingh Onnes , noted in an earlier chapter for his Ph.D. dissertation on the Foucault pendulum, made his mark in the world of science for great discoveries in low temperature physics. Three years after receiving his degree in 1879, Onnes ascended to the chair in experimental physics at the University of Leiden in Holland. His research interest was low temperature physics and, like others in England and on the continent, he worked to achieve ever lower temperatures through the liquefaction of gases.
Drag and Lift
Authors: Darrigol Olivier 
Published: November 2023

Abstract
The problem of the forces that a fluid exerts on a solid body challenged hydrodynamics since d’Alembert’s foundational Essaiof 1752. It only found a quantitative, wide-ranging solution in the first third of the twentieth century, after a few partial successes in the nineteenth century and earlier. The first section of this chapter is devoted to these older attempts, including Newton’s molecular-impact theory, Rayleigh’s dead-water theory, and eddy-resistance theories by Poncelet and Saint-Venant. None of these theories truly succeeded in making quantitative predictions, and they all lacked a solid conceptual basis. Newton’s theory artificially neglected the mutual action of fluid molecules, Rayleigh’s implied an absurdly large wake, and Saint-Venant’s required some observational input. Yet they all contained important elements of the modern understanding of fluid resistance. Newton understood how a similitude argument constrained inertial resistance to be quadratic. Rayleigh’s theory foreshadowed the separation process now admitted for non-streamlined flow. Saint-Venant correctly described the eddy resistance resulting from the instability of separated flow.
Section 7.2 is devoted to ship resistance. The development of steam navigation in the Victorian empire motivated the efforts of a few learned engineers to reflect on the optimal shape of ship hulls. John Scott Russell saw how to minimize wave resistance. William Rankine clearly distinguished skin friction, large-eddy resistance, and wave resistance. Lastly, and most importantly, William Froude expressed the conditions for a rational use of models and developed the relevant experimental techniques. In his analysis of skin friction, he finely described what Prandtl later called a turbulent boundary layer. His and Rankine’s insights into the mechanisms of high-Reynolds-number resistance nevertheless remained qualitative. The means were still lacking to turn them into efficient computational schemes.
Murder on the Highway
Authors: Morgan Michael 
Published: November 2023

Abstract
Type the words ‘retina’, ‘murder’ and ‘image’ into a Web search engine and one is soon led to the novel ‘The Story of Sevenoaks’, written in 1875 by the popular Dr J. G. Holland. ‘Sevenoaks’ has not worn well, but here is a re´sume´: ‘General’ Belcher, President of the Crooked Valley Railroad, and purveyor of the suspect Belcher rifle to the Prussian government, has forged the signature of Nicholas Johnston, for personal advantage. He is confronted in court by an expert on handwriting and chemistry. The expert is certain that the disputed signature is a forgery.
‘Whirling madly through the darkness’
Authors: Morgan Michael 
Published: November 2023

Abstract
For it always happened that when I awoke like this, and my mind struggled in an unsuccessful attempt to discover where I was, everything would be moving about me through the darkness: things, places, years. My body, still too heavy with sleep to move, would make an effort to construe the form which its tiredness took as an orientation of its various members, so as to induce from that where the wall lay and the furniture stood, to piece together and give a name to the house in which it must be living. Its memory, the composite memory of its ribs, knees and shoulder blades offered it a whole series of rooms in which it had at one time or another slept; while the unseen walls kept changing, adapting themselves to the shape of each successive room that it remembered, whirling madly through the darkness.
Who Killed the Chauffeur?
Authors: Morgan Michael 
Published: November 2023

Abstract
In Raymond Chandler’s novel The Big Sleep (1939), Owen Taylor is the chauffeur for the Sternwood family. Early in the book he is found dead at the wheel of one of the Sternwood cars in the surf off Lido fish pier. Private Investigator Philip Marlowe is present as the police and the medical examiner argue about whether Taylor’s death is murder or suicide. The ME thinks he was blackjacked before hitting the water.
Where is Fancy Bred?
Authors: Morgan Michael 
Published: November 2023

Abstract
The history of electrical stimulation of the brain starts with the experiments of Benjamin Franklin in the eighteenth century. Early results were not exactly encouraging. A pullet given a powerful electric shock ran headlong against a wall, and ‘on examination appeared perfectly blind’. A turkey of 10 lb weight was even less fortunate and was struck stone dead, but did ‘eat uncommonly tender’ (an argument not yet advanced by advocates of the electric chair, oddly enough).
Into the Mill
Authors: Morgan Michael 
Published: November 2023

Abstract
If we imagine that there is a machine whose structure makes it think, sense, and have perceptions, we could conceive it enlarged, having the same proportions, so that we could enter it, as one enters into a mill. Assuming that, when inspecting its interior, we will only find parts that push against each other, and we will never find anything to explain the perception. (G. W. Leibniz, The Monadology) The problem with Leibniz’s argument is that it assumes the truth of its conclusion in its premise – the error called petitio principi in the medievalschools.
Indistinguishability At A Distance
Authors: Scarani Valerio 
Published: November 2023

Abstract
During my first lecture at Saint-Michel College, I had sidestepped the question about randomness that the student had asked. As the reader will recall, it was the experiment of Fig. 1.1, as simple as it was, in which the particles arrived one after the other at a beam splitter. I had said that we do not know how to describe the behaviour of each particle, we do not know why a given particle is reﬂected rather than transmitted. Is it really uncertain, ran- dom (which is the current opinion among physicists) or is there a mechanism yet to be discovered? I had deliberately turned attention from this problem, in order to concentrate on the experiment of Fig. 1.3, the Mach–Zehnder interferometer. We have seen, then, that quantum randomness is a curious randomness – if we assemble two ‘randomness generators’ (beam splitters) in a certain way, we rediscover the certainty! I brieﬂy remind the assembled students of this, a week later, in the old granary of the College.
Orsay, Innsbruck, Geneva
Authors: Scarani Valerio 
Published: November 2023

Abstract
‘Do you have a permanent position?’. The young Alain Aspect, visiting John Bell in Geneva, was speechless for a moment. Alain has an ambitious objective for his doctoral thesis – to perform, in the optics laboratory at the Paris-Sud University at Orsay, an experiment that allows him to measure correlations between two particles and to see if Bell’s inequality is violated. An ambitious project. But the majority of the scientific community continues to regard Bell inequalities, non-locality, as ‘philosophy’. John Bell, then, is expressing legitimate concern for the future of the young man who has come to talk with him, who risks finding himself marginalized if he goes on with his project. ‘Do you have a permanent position?’. Yes, Alain has a permanent position, a small salary guaranteed for life – but he risks his prestige. The risk will pay off – Alain will perform his doctoral project and he will even have the pleasure of seeing the scientific community calling his experiment ‘the Aspect experiment’, with a worthy recognition that is not always guaranteed.
Traits, invariants, and theories of everything
Authors: Mayhew Peter J 
Published: November 2023

Abstract
The last two chapters were concerned with how natural selection can change the way a lineage looks (its phenotype). These changes have had profound effects, first on the complexity of organisms (Chapter 2), and second on the complexity of the ecology of the planet (Chapter 3). This chapter continues the theme, but deals with traits that are individually far more ordinary: life history traits. Nonetheless, they account for much of the diversity in form across species, thus collectively are of immense interest. A life history is a description of the major characteristics of an organism from its birth to its death. The traits are variables that can be measured or categorized across individuals and that collectively make up the description (Figure 4.1). In the past, most work on life history evolution proceeded on a trait-by-trait basis.
Doing adaptive things
Authors: Mayhew Peter J 
Published: November 2023

Abstract
Most of the traits we have considered so far involve characteristics that differ between populations or species, such as their average sex ratio, their average lifespan, and whether they are sexual or asexual. Individual organisms also possess the ability to modify what they do in response to changes they sense in their environment during their lifetime. In animals, where much of this change involves differences in what they do, we call this behaviour. In plants the differences result from changes in growth, development, and morphology.
Evolution and numbers
Authors: Mayhew Peter J 
Published: November 2023

Abstract
So far we have covered how ecology causes anagenetic change, the place of ecology being largely subsumed under the term ‘selection’. The present chapter, like Chapter 3, explores more the effect of evolution on ecology, thus closing a causation loop. Specifically, we will investigate the effects of anagenetic change on population dynamics, an ecological characteristic, and ask whether we can better understand population level phenomena by incorporating evolutionary assumptions. Further, we will explore an additional theoretical step in the evolutionary process by using assumptions about population dynamics to help estimate the path of evolutionary change. Thus, evolution influences ecology, which influences evolution again.
Birth of species
Authors: Mayhew Peter J 
Published: November 2023

Abstract
Until now we have been concerned almost exclusively with evolutionary change within lineages—anagenesis. Anagenesis creates differences between lineages and hence the diversity of form and function that we observe as a major feature of our planet. It is, however, just one of the two major evolutionary processes, the other being cladogenesis. Cladogenesis is the creation of new lineages, speciation. Cladogenesis and anagenesis are jointly responsible for life’s diversity: without cladogenesis, anagenesis could not realize life’s potential for phenotypic diversity. Without anagenesis, as we shall see, speciation could not occur.
First Interlude: Wason ‘S Selection Task
Authors: Chiswell Ian , Hodges Wilfrid 
Published: November 2023

Abstract
These results are fairly typical. There are several ways of adjusting the experiment, and a good deal is known about which adjustments make it easier or harder to reach the ‘logically correct’ answer. One possible explanation is that human beings do not have any built-in understanding of truth tables. We can make quick decisions on the basis of rules that evolution built into us, and for some reason these rules tell us to choose card E but not card 7 in this experiment. Psychologists have made various suggestions of why this should be. An explanation should also explain why certain versions of the experiment make the task easier and some make it harder. See, for example, Keith E. Stanovich, Who is Rational? Studies of Individual Differences in Reasoning, Lawrence Erlbaum, Mahwah, NJ, 1999, or Keith Stenning, Seeing Reason: Image and Language in Learning to Think, Oxford University Press, Oxford, 2002.
First-Order Logic
Authors: Chiswell Ian , Hodges Wilfrid 
Published: November 2023

Abstract
Now we turn to arguments that involve quantifier expressions ‘There is’ and ‘For all‐, as we promised at the beginning of Chapter 5. We study what these expressions mean in mathematics (Sections 7.1–7.2), we build a formal semantics that gives necessary and suﬃcient conditions for a first-order sentence to be true in a structure (Section 7.3), we find natural deduction rules for these sentences (Section 7.4) and we prove a completeness theorem for the proof calculus got by adding these rules to those of earlier chapters (Section 7.6). The logic that we reach by adding these expressions and rules is called first-order logic. Sometimes you will also hear it called predicate logic or elementary logic or classical logic. Do not confuse it with traditional logic, which is the logic that was studied up till the middle of the nineteenth century—see (7.8) below.