615 research outputs found
Moving Mirrors and Thermodynamic Paradoxes
Quantum fields responding to "moving mirrors" have been predicted to give
rise to thermodynamic paradoxes. I show that the assumption in such work that
the mirror can be treated as an external field is invalid: the exotic
energy-transfer effects necessary to the paradoxes are well below the scales at
which the model is credible. For a first-quantized point-particle mirror, it
appears that exotic energy-transfers are lost in the quantum uncertainty in the
mirror's state. An accurate accounting of these energies will require a model
which recognizes the mirror's finite reflectivity, and almost certainly a model
which allows for the excitation of internal mirror modes, that is, a
second-quantized model.Comment: 7 pages, Revtex with Latex2
Closing International Law\u27s Innocence Gap
Over the last decade, a growing number of countries have adopted new laws and other mechanisms to address a gap in national criminal legal systems: the absence of meaningful procedures to raise post-conviction claims of factual innocence. These legal and policy reforms have responded to a global surge of exonerations facilitated by the growth of national innocence organizations that increasingly collaborate across borders. It is striking that these developments have occurred with little direct help from international law. Although many treaties recognize extensive fair trial and appeal rights, no international human rights instrument—in its text, existing interpretation, or implementation—explicitly and fully recognizes the right to assert a claim of factual innocence. We label this omission international law’s innocence gap. The gap appears increasingly anomalous given how foundational innocence protection has become at the national level, as well as international law’s longstanding commitment to the presumption of innocence, fair trial, and other criminal process guarantees. We argue the time has come to close this innocence gap by recognizing a new international human right to assert post-trial claims of factual innocence
A general worldline quantum inequality
Worldline quantum inequalities provide lower bounds on weighted averages of
the renormalised energy density of a quantum field along the worldline of an
observer. In the context of real, linear scalar field theory on an arbitrary
globally hyperbolic spacetime, we establish a worldline quantum inequality on
the normal ordered energy density, valid for arbitrary smooth timelike
trajectories of the observer, arbitrary smooth compactly supported weight
functions and arbitrary Hadamard quantum states. Normal ordering is performed
relative to an arbitrary choice of Hadamard reference state. The inequality
obtained generalises a previous result derived for static trajectories in a
static spacetime. The underlying argument is straightforward and is made
rigorous using the techniques of microlocal analysis. In particular, an
important role is played by the characterisation of Hadamard states in terms of
the microlocal spectral condition. We also give a compact form of our result
for stationary trajectories in a stationary spacetime.Comment: 19pp, LaTeX2e. The statement of the main result is changed slightly.
Several typos fixed, references added. To appear in Class Quantum Gra
Copyright Exceptions Across Borders: Implementing the Marrakesh Treaty
This article reviews state ratification and implementation of the Marrakesh Treaty since its conclusion in 2013. We find that most states have adhered closely to the Treaty’s text, thus creating a de facto global template of exceptions and limitations that has increasingly enabled individuals with print disabilities, libraries and schools to create accessible format copies and share them across borders. The article argues that the Marrakesh Treaty’s core innovation—mandatory exceptions to copyright to promote public welfare—together with consultations with a diverse range of stakeholders, may offer a model for harmonising human rights and IP in other contexts
The Molecular Connection to the FIR-Radio Continuum Correlation in Galaxies
We have studied the relationships between the radio continuum (RC) and CO
emission for a set of galaxies selected from the BIMA Survey of Nearby
Galaxies. We find that the global CO-RC correlation is as tight as the global
FIR-RC correlation for the 24 galaxies studied. Within 9 galaxies with ~6
arcsec CO and RC data available, the CO and RC emission is as tightly
correlated as its global value; the radially averaged correlation is nearly
linear, extends over four order of magnitude and holds down to the smallest
linear resolution of the observations, which is ~100 pc. We define qco as the
log of the ratio of the CO to RC flux as a way to characterize the CO-RC
correlation. Combining 6 arcsec pixel-by-pixel comparisons across all sources
yields an average small-scale correlation of qco = 1.1 +/- 0.28; that is, the
spatially resolved correlation has a dispersion that is less than a factor of
2. There are however systematic variations in the CO/RC ratio; the strongest
organized structures in qco tend to be found along spiral arms and on size
scales much larger than the resolution of the observations. We do not measure
any systematic trend in CO/RC ratio as a function of radius in galaxies. The
constancy of the CO/RC ratio stands in contrast to the previously measured
decrease in the FIR/RC ratio as a function of radius in galaxies. We suggest
that the excellent correlation between the CO, RC and FIR emission in galaxies
is a consequence of regulation by hydrostatic pressure; this model links all
three emissions without invoking an explicit dependence on a star formation
scenario.Comment: Accepted by A&A, 25 pages, 10 figures. For a version with high
quality figures, see http://lucipher.ca.astro.it/~matteo/rc-co/paper.ps.g
Dynamics of viscoelastic membranes
We determine both the in-plane and out-of-plane dynamics of viscoelastic
membranes separating two viscous fluids in order to understand microrheological
studies of such membranes. We demonstrate the general viscoelastic signatures
in the dynamics of shear, bending, and compression modes. We also find a
screening of the otherwise two-dimensional character of the response to point
forces due to the presence of solvent. Finally, we show that there is a linear,
hydrodynamic coupling between the in-plane compression modes of the membrane
and the out-of-plane bending modes in the case where the membrane separates two
different fluids or environments
Relativistic drag forces on black holes from scalar dark matter clouds of all sizes
We use numerical simulations of scalar field dark matter evolving on a moving black hole background to confirm the regime of validity of (semi)analytic expressions derived from first principles for both dynamical friction and momentum accretion in the relativistic regime. We cover both small and large clouds (relative to the de Broglie wavelength of the scalars), and light and heavy particle masses (relative to the black hole size). In the case of a small dark matter cloud, the effect of accretion is a non-negligible contribution to the total force on the black hole, even for small scalar masses. We confirm that this momentum accretion transitions between two regimes (wave and particlelike) and we identify the mass of the scalar at which the transition between regimes occurs
Two dimensional Sen connections and quasi-local energy-momentum
The recently constructed two dimensional Sen connection is applied in the
problem of quasi-local energy-momentum in general relativity. First it is shown
that, because of one of the two 2 dimensional Sen--Witten identities, Penrose's
quasi-local charge integral can be expressed as a Nester--Witten integral.Then,
to find the appropriate spinor propagation laws to the Nester--Witten integral,
all the possible first order linear differential operators that can be
constructed only from the irreducible chiral parts of the Sen operator alone
are determined and examined. It is only the holomorphy or anti-holomorphy
operator that can define acceptable propagation laws. The 2 dimensional Sen
connection thus naturally defines a quasi-local energy-momentum, which is
precisely that of Dougan and Mason. Then provided the dominant energy condition
holds and the 2-sphere S is convex we show that the next statements are
equivalent: i. the quasi-local mass (energy-momentum) associated with S is
zero; ii.the Cauchy development is a pp-wave geometry with pure
radiation ( is flat), where is a spacelike hypersurface
whose boundary is S; iii. there exist a Sen--constant spinor field (two spinor
fields) on S. Thus the pp-wave Cauchy developments can be characterized by the
geometry of a two rather than a three dimensional submanifold.Comment: 20 pages, Plain Tex, I
Constitutional Analogies in the International Legal System
This Article explores issues at the frontier of international law and constitutional law. It considers five key structural and systemic challenges that the international legal system now faces: (1) decentralization and disaggregation; (2) normative and institutional hierarchies; (3) compliance and enforcement; (4) exit and escape; and (5) democracy and legitimacy. Each of these issues raises questions of governance, institutional design, and allocation of authority paralleling the questions that domestic legal systems have answered in constitutional terms. For each of these issues, I survey the international legal landscape and consider the salience of potential analogies to domestic constitutions, drawing upon and extending the writings of international legal scholars and international relations theorists. I also offer some preliminary thoughts about why some treaties and institutions, but not others, more readily lend themselves to analysis in constitutional terms. And I distinguish those legal and political issues that may generate useful insights for scholars studying the growing intersections of international and constitutional law from other areas that may be more resistant to constitutional analogies
Vacuum Polarization and Energy Conditions at a Planar Frequency Dependent Dielectric to Vacuum Interface
The form of the vacuum stress-tensor for the quantized scalar field at a
dielectric to vacuum interface is studied. The dielectric is modeled to have an
index of refraction that varies with frequency. We find that the stress-tensor
components, derived from the mode function expansion of the Wightman function,
are naturally regularized by the reflection and transmission coefficients of
the mode at the boundary. Additionally, the divergence of the vacuum energy
associated with a perfectly reflecting mirror is found to disappear for the
dielectric mirror at the expense of introducing a new energy density near the
surface which has the opposite sign. Thus the weak energy condition is always
violated in some region of the spacetime. For the dielectric mirror, the mean
vacuum energy density per unit plate area in a constant time hypersurface is
always found to be positive (or zero) and the averaged weak energy condition is
proven to hold for all observers with non-zero velocity along the normal
direction to the boundary. Both results are found to be generic features of the
vacuum stress-tensor and not necessarily dependent of the frequency dependence
of the dielectric.Comment: 16 pages, 4 figures, Revtex style Minor typographic corrections to
equations and tex
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