1,017 research outputs found
Reconstructing Bohr's Reply to EPR in Algebraic Quantum Theory
Halvorson and Clifton have given a mathematical reconstruction of Bohr's
reply to Einstein, Podolsky and Rosen (EPR), and argued that this reply is
dictated by the two requirements of classicality and objectivity for the
description of experimental data, by proving consistency between their
objectivity requirement and a contextualized version of the EPR reality
criterion which had been introduced by Howard in his earlier analysis of Bohr's
reply. In the present paper, we generalize the above consistency theorem, with
a rather elementary proof, to a general formulation of EPR states applicable to
both non-relativistic quantum mechanics and algebraic quantum field theory; and
we clarify the elements of reality in EPR states in terms of Bohr's
requirements of classicality and objectivity, in a general formulation of
algebraic quantum theory.Comment: 13 pages, Late
Innovation and Responsibility: Librarians in an Era of Generative AI, Inequality, and Information Overload
In an era marked by generative AI, widening inequality, and information overload, librarians with LIS training find themselves at the forefront of a changing landscape. The traditional paradigm in academia is challenged by new technologies and social shifts, prompting a reassessment the librarian\u27s role as a public leader. This article discusses three perspectives on these issues, placing them within the larger conversation of the LIS field. Dr. Norman Mooradian lays the groundwork for a paradigm shift by exploring the intersection of knowledge and ethics in a knowledge economy. Boheme Morris delves into the complexities of inequality within the high-tech knowledge economy, challenging the efficacy of the access doctrine. Sarah Wilson\u27s research emphasizes the need for diversity, equity, and inclusion in knowledge access, and sounds a clarion call for library services to do more in the furtherance of DEI
Quantum Steering and Space-Like Separation
In non-relativistic quantum mechanics, measurements performed by separate
observers are modeled via tensor products. In Algebraic Quantum Field Theory,
though, local observables corresponding to space-like separated parties are
just required to commute. The problem of determining whether these two
definitions of "separation" lead to the same set of bipartite correlations is
known in non-locality as Tsirelson's problem. In this article, we prove that
the analog of Tsirelson's problem in steering scenarios is false. That is,
there exists a steering inequality that can be violated or not depending on how
we define space-like separation at the operator level.Comment: Some typos corrected. Short discussion about Algebraic Quantum Field
Theory. Modified introduction and conclusio
A Preliminary List of the Crane Flies (Diptera: Tipulidae) of Iowa
The members of the family Tipulidae are commonly called Crane flies. They have slender bodies, long slim wings, prominent halteres and long dangling legs. The legs break so readily between the trochanter and femur that it becomes a difficult problem to collect these insects and get them mounted in good condition. 1 This brittleness might almost be made a character for determination of the family. The antennae are long and slim and are composed of from six to thirty-nine jointed segments. The eyes are large and the ocelli are wanting. In size the various species show a range almost as great as that found in the entire order of Diptera; the wing expanse varying from about two millimeters to forty-five millimeters or more
Non-singular inflationary universe from polymer matter
We consider a polymer quantization of a free massless scalar field in a
homogeneous and isotropic cosmological spacetime. This quantization method
assumes that field translations are fundamentally discrete, and is related to
but distinct from that used in loop quantum gravity. The semi-classical
Friedman equation yields a universe that is non-singular and non-bouncing,
without quantum gravity. The model has an early de Sitter-like inflationary
phase with sufficient expansion to resolve the horizon and entropy problems,
and a built in mechanism for a graceful exit from inflation.Comment: 4 pages, 1 figure; v2 clarifications added, reference update
Semiclassical states for quantum cosmology
In a metric variable based Hamiltonian quantization, we give a prescription
for constructing semiclassical matter-geometry states for homogeneous and
isotropic cosmological models. These "collective" states arise as infinite
linear combinations of fundamental excitations in an unconventional "polymer"
quantization. They satisfy a number of properties characteristic of
semiclassicality, such as peaking on classical phase space configurations. We
describe how these states can be used to determine quantum corrections to the
classical evolution equations, and to compute the initial state of the universe
by a backward time evolution.Comment: 13 page
Effective Polymer Dynamics of D-Dimensional Black Hole Interiors
We consider two different effective polymerization schemes applied to
D-dimensional, spherically symmetric black hole interiors. It is shown that
polymerization of the generalized area variable alone leads to a complete,
regular, single-horizon spacetime in which the classical singularity is
replaced by a bounce. The bounce radius is independent of rescalings of the
homogeneous internal coordinate, but does depend on the arbitrary fiducial cell
size. The model is therefore necessarily incomplete. It nonetheless has many
interesting features: After the bounce, the interior region asymptotes to an
infinitely expanding Kantowski-Sachs spacetime. If the solution is analytically
continued across the horizon, the black hole exterior exhibits asymptotically
vanishing quantum-corrections due to the polymerization. In all spacetime
dimensions except four, the fall-off is too slow to guarantee invariance under
Poincare transformations in the exterior asymptotic region. Hence the
four-dimensional solution stands out as the only example which satisfies the
criteria for asymptotic flatness. In this case it is possible to calculate the
quantum-corrected temperature and entropy. We also show that polymerization of
both phase space variables, the area and the conformal mode of the metric,
generically leads to a multiple horizon solution which is reminiscent of
polymerized mini-superspace models of spherically symmetric black holes in Loop
Quantum Gravity.Comment: 14 pages, 4 figures. Added discussion about the dependency on
auxiliary structures. Matches with the published versio
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