5,002 research outputs found
The ambivalent shadow of the pre-Wilsonian rise of international law
The generation of American international lawyers who founded the American Society of International Law in 1906 and nurtured the soil for what has been retrospectively called a “moralistic legalistic approach to international relations” remains little studied. A survey of the rise of international legal literature in the U.S. from the mid-19th century to the eve of the Great War serves as a backdrop to the examination of the boosting effect on international law of the Spanish American War in 1898. An examination of the Insular Cases before the US Supreme Court is then accompanied by the analysis of a number of influential factors behind the pre-war rise of international law in the U.S. The work concludes with an examination of the rise of natural law doctrines in international law during the interwar period and the critiques addressed.by the realist founders of the field of “international relations” to the “moralistic legalistic approach to international relation
Improving the Efficiency of an Ideal Heat Engine: The Quantum Afterburner
By using a laser and maser in tandem, it is possible to obtain laser action
in the hot exhaust gases involved in heat engine operation. Such a "quantum
afterburner" involves the internal quantum states of working gas atoms or
molecules as well as the techniques of cavity quantum electrodynamics and is
therefore in the domain of quantum thermodynamics. As an example, it is shown
that Otto cycle engine performance can be improved beyond that of the "ideal"
Otto heat engine.Comment: 5 pages, 3 figure
The Chagos Islands cases: the empire strikes back
Good governance requires the accommodation of multiple interests in the cause of decision making. However, undue regard for particular sectional interests can take their toll upon public faith in government administration. Historically, broad conceptions of the good of the commonwealth were employed to outweigh the interests of groups that resisted colonisation. In the decision making of the British Empire, the standard approach for justifying the marginalisation of the interests of colonised groups was that they were uncivilised and that particular hardships were the price to be paid for bringing to them the imperial dividend of industrial society. It is widely assumed that with the dismantling of the British Empire, such impulses and their accompanying jurisprudence became a thing of the past. Even as decolonisation proceeded apace after the Second World War, however, the United Kingdom maintained control of strategically important islands with a view towards sustaining its global role. In an infamous example from this twilight period of empire, in the 1960s imperial interests were used to justify the expulsion of the Chagos islanders from the British Indian Ocean Territory (BIOT). Into the twenty-first century, this forced elision of the UK’s interests with the imperial “common good” continues to take centre stage in courtroom battles over the islanders’ rights, being cited before domestic and international tribunals in order to maintain the Chagossians’ exclusion from their homeland. This article considers the new jurisprudence of imperialism which has emerged in a string of decisions which have continued to marginalise the Chagossians’ interests
Effects of motion in cavity QED
We consider effects of motion in cavity quantum electrodynamics experiments
where single cold atoms can now be observed inside the cavity for many Rabi
cycles. We discuss the timescales involved in the problem and the need for good
control of the atomic motion, particularly the heating due to exchange of
excitation between the atom and the cavity, in order to realize nearly unitary
dynamics of the internal atomic states and the cavity mode which is required
for several schemes of current interest such as quantum computing. Using a
simple model we establish ultimate effects of the external atomic degrees of
freedom on the action of quantum gates. The perfomance of the gate is
characterized by a measure based on the entanglement fidelity and the motional
excitation caused by the action of the gate is calculated. We find that schemes
which rely on adiabatic passage, and are not therefore critically dependent on
laser pulse areas, are very much more robust against interaction with the
external degrees of freedom of atoms in the quantum gate.Comment: 10 pages, 5 figures, REVTeX, to be published in Walls Symposium
Special Issue of Journal of Optics
Critical Exponents of the Three Dimensional Random Field Ising Model
The phase transition of the three--dimensional random field Ising model with
a discrete () field distribution is investigated by extensive Monte
Carlo simulations. Values of the critical exponents for the correlation length,
specific heat, susceptibility, disconnected susceptibility and magnetization
are determined simultaneously via finite size scaling. While the exponents for
the magnetization and disconnected susceptibility are consistent with a first
order transition, the specific heat appears to saturate indicating no latent
heat. Sample to sample fluctuations of the susceptibilty are consistent with
the droplet picture for the transition.Comment: Revtex, 10 pages + 4 figures included as Latex files and 1 in
Postscrip
Biot-Savart-like law in electrostatics
The Biot-Savart law is a well-known and powerful theoretical tool used to
calculate magnetic fields due to currents in magnetostatics. We extend the
range of applicability and the formal structure of the Biot-Savart law to
electrostatics by deriving a Biot-Savart-like law suitable for calculating
electric fields. We show that, under certain circumstances, the traditional
Dirichlet problem can be mapped onto a much simpler Biot-Savart-like problem.
We find an integral expression for the electric field due to an arbitrarily
shaped, planar region kept at a fixed electric potential, in an otherwise
grounded plane. As a by-product we present a very simple formula to compute the
field produced in the plane defined by such a region. We illustrate the
usefulness of our approach by calculating the electric field produced by planar
regions of a few nontrivial shapes.Comment: 14 pages, 6 figures, RevTex, accepted for publication in the European
Journal of Physic
Finite-temperature Screening and the Specific Heat of Doped Graphene Sheets
At low energies, electrons in doped graphene sheets are described by a
massless Dirac fermion Hamiltonian. In this work we present a semi-analytical
expression for the dynamical density-density linear-response function of
noninteracting massless Dirac fermions (the so-called "Lindhard" function) at
finite temperature. This result is crucial to describe finite-temperature
screening of interacting massless Dirac fermions within the Random Phase
Approximation. In particular, we use it to make quantitative predictions for
the specific heat and the compressibility of doped graphene sheets. We find
that, at low temperatures, the specific heat has the usual normal-Fermi-liquid
linear-in-temperature behavior, with a slope that is solely controlled by the
renormalized quasiparticle velocity.Comment: 9 pages, 5 figures, Submitted to J. Phys.
Visibility diagrams and experimental stripe structure in the quantum Hall effect
We analyze various properties of the visibility diagrams that can be used in
the context of modular symmetries and confront them to some recent experimental
developments in the Quantum Hall Effect. We show that a suitable physical
interpretation of the visibility diagrams which permits one to describe
successfully the observed architecture of the Quantum Hall states gives rise
naturally to a stripe structure reproducing some of the experimental features
that have been observed in the study of the quantum fluctuations of the Hall
conductance. Furthermore, we exhibit new properties of the visibility diagrams
stemming from the structure of subgroups of the full modular group.Comment: 8 pages in plain TeX, 7 figures in a single postscript fil
Noether symmetries for two-dimensional charged particle motion
We find the Noether point symmetries for non-relativistic two-dimensional
charged particle motion. These symmetries are composed of a quasi-invariance
transformation, a time-dependent rotation and a time-dependent spatial
translation. The associated electromagnetic field satisfy a system of
first-order linear partial differential equations. This system is solved
exactly, yielding three classes of electromagnetic fields compatible with
Noether point symmetries. The corresponding Noether invariants are derived and
interpreted
Yang--Mills sphalerons in all even spacetime dimensions , : =3,4
The classical solutions to higher dimensional Yang--Mills (YM) systems, which
are integral parts of higher dimensional Einstein--YM (EYM) systems, are
studied. These are the gravity decoupling limits of the fully gravitating EYM
solutions. In odd spacetime dimensions, depending on the choice of gauge group,
these are either topologically stable or unstable. Both cases are analysed, the
latter numerically only. In even spacetime dimensions they are always unstable,
describing saddle points of the energy, and can be described as {\it
sphalerons}. This instability is analysed by constructing the noncontractible
loops and calculating the Chern--Simons (CS) charges, and also perturbatively
by numerically constructing the negative modes. This study is restricted to the
simplest YM system in spacetime dimensions , which is amply
illustrative of the generic case.Comment: 16 pages, 3 figures ; comments added, to appear in J. Phys.
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