Non-linear electrodynamics : a classical view of the quantum vacuum

Non-linear electrodynamics represents an extension to Maxwell electrodynamics which can describe a range of effects related to high-field physics. We give an overview of recent work looking at various aspects of such theories

On the energy-momentum of light : an all optical view of the Abraham-Minkowski controversy

The energy-momentum of light in a medium is known to have two conflicting descriptions, due to Abraham and Minkowski. In non-linear electrodynamics, a strong field can cause the vacuum to behave analogously to a dielectric material. We investigate the Abraham-Minkowski controversy in this context, and show that for non-linear electrodynamics in vacuum, the Minkowski description is the most natural

Electron beam cooling in intense focussed laser pulses

In the coming years, a new generation of high-power laser facilities (such as the Extreme Light Infrastructure) will become operational, for which it is important to understand how the interaction with intense laser pulses affects the bulk properties of relativistic electron bunches. At such high field intensities, we expect both radiation reaction and quantum effects to have a dominant role to play in determining the dynamics. The reduction in relative energy spread (beam cooling) at the expense of mean beam energy predicted by classical theories of radiation reaction has been shown to occur equally in the longitudinal and transverse directions, whereas this symmetry is broken when the theory is extended to approximate certain quantum effects. The reduction in longitudinal cooling suggests that the effects of radiation reaction could be better observed in measurements of the transverse distribution, which for real-world laser pulses motivates the investigation of the angular dependence of the interaction. Using a stochastic single-photon emission model with a (Gaussian beam) focussed pulse, we find strong angular dependence of the stochastic heating

On the energy-momentum tensor of light in strong fields : an all optical view of the Abraham-Minkowski controversy

The Abraham-Minkowski controversy is the debate surrounding the "correct" form of the energy-momentum tensor of light in a medium. Over a century of theoretical and experimental studies have consistently produced conflicting results, with no consensus being found on how best to describe the influence of a material on the propagation of light. It has been argued that the total energy-momentum tensor for each of the theories, which includes both wave and material components, are equal. The difficulty in separating the full energy-momentum tensor is generally attributed to the fact that one cannot obtain the energy-momentum tensor of the medium for real materials. Non-linear electrodynamics provides an opportunity to approach the debate from an all optical set up, where the role of the medium is replaced by the vacuum under the influence of a strong background field. We derive, from first principles, the general form of the energy-momentum tensor in such theories, and use our results to shed some light on this long standing issue

Vested Patents and Equal Justice

In a time of renewed interest in equal justice, the vested patent right may be timely again. Vested patent rights helped marginalized Americans to secure equal justice earlier in American history. And they helped to make sense of the law. Vested patent rights can perform those tasks again today. The concept of vested rights render patent law coherent. And it explains patent law’s interactions with other areas of law, such as property, administrative, and constitutional law. The vested rights doctrine also can serve the requirements of equal justice, as it has several times in American history. Vested rights secure justice for vulnerable minorities against majority factions. They resist the tendency of law to devolve into power. And they solve practical problems consistent with what we owe each other as equal agents of practical reason

Opus as the Core of Property

No account of property law can achieve a comprehensive understanding without factoring in natural rights. Professor Eric Claeys’s new book offers a significant contribution to contemporary property theory by setting out the most comprehensive and defensible theory of natural property rights to appear in a long time. Claeys describes the function of property as productive work. Intentional planning, purposeful effort, and creative ordering enable people to achieve lives of flourishing. And, as Claeys demonstrates in careful detail, the various norms and institutions of property law make possible those exercises of practical reason and the flourishing that results from them. Natural property rights turn out to have both pragmatic utility and ethical value. They enable human beings to flourish both materially and as reasoning, choosing, moral agents

Vested Patents and Equal Justice,

In a time of renewed interest in equal justice, the vested patent right may be timely again. Vested patent rights helped marginalized Americans to secure equal justice earlier in American history. And they helped to make sense of the law. Vested patent rights can perform those tasks again today. The concept of vested rights render patent law coherent. And it explains patent law \u27s interactions with other areas of law, such as property, administrative, and constitutional law. The vested rights doctrine also can serve the requirements of equal justice, as it has several times in American history. Vested rights secure justice for vulnerable minorities against majority factions. They resist the tendency of law to devolve into power. And they solve practical problems consistent with what we owe each other as equal agents of practical reason

The Law as Bard: Extolling a Culture\u27s Virtues, Exposing Its Vices, and Telling Its Story

Before literacy rates in the English speaking world reached their apex (and long before they dropped into the trough they are now thought to occupy), before we commoners read newspapers (and long before we wrote blogs), before autobiographies crowded book shelves (and long before reality television created celebrities out of rather mean raw material), our cultural forebears appointed a rather singular individual to preserve for their children a record of their values, rituals, institutions, and assumptions: the bard. The bard told stories. But the bard didn\u27t tell just any stories. The bard told stories drawn from the fabric of which his culture consisted. The bard\u27s stories, while entertaining, also served a much more lasting purpose, that of teaching, and in teaching, affirming, what choices his society valued. In particular, by reading the bard\u27s stories one can identify which virtues (always courage and love, sometimes charity and chastity) the bard\u27s society honored and which vices (always cowardice and cruelty, sometimes intemperance) it condemned. The bard extracted from his culture\u27s fabric samples representative of the whole. In short, the bard reinforced for his contemporaries and identified for his successors what choices and cultural commitments his society considered right and good. A society\u27s laws function in much the same ways. The law contains a narrative, which has two aspects, (1) preservation of an account of human choices and cultural commitments, which reflects the culture\u27s values and (2) instruction that informs and shapes future choices. In other words, the law\u27s narrative preserves samples of a cultural fabric for the benefit of contemporary and future generations, and in turn teaches which individual and cultural choices are just. The preservation function of the legal narrative is most easily discerned in judicial decisions, in which courts tell stories about particular human choices, which are meant to be representative of the choices participants in a culture make generally. A judicial decision literally renders judgment on the rightness of a particular human choice. That judgment rests upon, among other things, cultural assumptions about what is good and virtuous, as well as conclusions about what is efficacious and useful. When read later, the decision reveals a tale of an individual who came to a crossroads and chose one course and not another. The decision also preserves the culture\u27s expression of approbation or disapprobation of that choice