15,225 research outputs found
Exact Green's Function of the reversible diffusion-influenced reaction for an isolated pair in 2D
We derive an exact Green's function of the diffusion equation for a pair of
spherical interacting particles in 2D subject to a back-reaction boundary
condition.Comment: 6 pages, 1 Figur
Scavenger 0.1: A Theorem Prover Based on Conflict Resolution
This paper introduces Scavenger, the first theorem prover for pure
first-order logic without equality based on the new conflict resolution
calculus. Conflict resolution has a restricted resolution inference rule that
resembles (a first-order generalization of) unit propagation as well as a rule
for assuming decision literals and a rule for deriving new clauses by (a
first-order generalization of) conflict-driven clause learning.Comment: Published at CADE 201
Dynamical Stability of Witten Rings
The dynamical stability of cosmic rings, or vortons, is investigated for the
particular equation of state given by the Witten bosonic model. It is found
that there exists a finite range of the state parameter for which the vorton
states are actually stable against dynamical perturbations. Inclusion of the
electromagnetic self action into the equation of state slightly shrinks the
stability region but otherwise yields no qualitative difference. If the Witten
bosonic model represents a good approximation for more realistic string models,
then the cosmological vorton excess problem can only be solved by assuming
either that strings are formed at low energy scales or that some quantum
instability may develop at a sufficient rate.Comment: 11 pages, LaTeX-ReVTeX (v.3), 2 figures available upon request, DAMTP
R-94/1
Study of the Science, Economics, and Perceptions Related to Implementation of Traditional and Innovative Stormwater Best Management Practices in Coastal South Carolina
2008 S.C. Water Resources Conference - Addressing Water Challenges Facing the State and Regio
Demonstrating Operating System Principles via Computer Forensics Exercises
We explore the feasibility of sparking student curiosity and interest in the core required MIS operating systems course through inclusion of computer forensics exercises into the course. Students were presented with two in-class exercises. Each exercise demonstrated an aspect of the operating system, and each exercise was written as a computer forensics investigation. Students were asked to indicate their perception of the practicality of the course material before and after completing the exercises. Based upon a t-test, we conclude that students find the course material to be of greater practical significance when course materials are linked to forensics topics
Quantum Games
In these lecture notes we investigate the implications of the identification
of strategies with quantum operations in game theory beyond the results
presented in [J. Eisert, M. Wilkens, and M. Lewenstein, Phys. Rev. Lett. 83,
3077 (1999)]. After introducing a general framework, we study quantum games
with a classical analogue in order to flesh out the peculiarities of game
theoretical settings in the quantum domain. Special emphasis is given to a
detailed investigation of different sets of quantum strategies.Comment: 13 pages (LaTeX), 3 figure
Recent developments in Vorton Theory
This article provides a concise overview of recent theoretical results
concerning the theory of vortons, which are defined to be (centrifugally
supported) equilibrium configurations of (current carrying) cosmic string
loops. Following a presentation of the results of work on the dynamical
evolution of small circular string loops, whose minimum energy states are the
simplest examples of vortons, recent order of magnitude estimates of the
cosmological density of vortons produced in various kinds of theoretical
scenario are briefly summarised.Comment: 6 pages Latex. Contribution to 1996 Cosmology Meeting, Peyresq,
Franc
Dark Energy and Modified Gravity
Despite two decades of tremendous experimental and theoretical progress, the
riddle of the accelerated expansion of the Universe remains to be solved. On
the experimental side, our understanding of the possibilities and limitations
of the major dark energy probes has evolved; here we summarize the major probes
and their crucial challenges. On the theoretical side, the taxonomy of
explanations for the accelerated expansion rate is better understood, providing
clear guidance to the relevant observables. We argue that: i) improving
statistical precision and systematic control by taking more data, supporting
research efforts to address crucial challenges for each probe, using
complementary methods, and relying on cross-correlations is well motivated; ii)
blinding of analyses is difficult but ever more important; iii) studies of dark
energy and modified gravity are related; and iv) it is crucial that R&D for a
vibrant dark energy program in the 2030s be started now by supporting studies
and technical R&D that will allow embryonic proposals to mature. Understanding
dark energy, arguably the biggest unsolved mystery in both fundamental particle
physics and cosmology, will remain one of the focal points of cosmology in the
forthcoming decade.Comment: 5 pages + references; science white paper submitted to the Astro2020
decadal surve
Radiative Torques on Interstellar Grains: II. Grain Alignment
Radiative torques on irregular dust grains, in addition to producing
superthermal rotation, play a direct dynamical role in the alignment of
interstellar dust with the local magnetic field. The equations governing the
orientation of spinning, precessing grains are derived; H_2 formation torques
and paramagnetic dissipation are included in the dynamics. Stationary solutions
(constant alignment angle and spin rate) are found; these solutions may be
stable ("attractors") or unstable ("repellors"). The equations of motion are
numerically integrated for three exemplary irregular grain geometries, exposed
to anisotropic radiation with the spectrum of interstellar starlight. The
resulting "trajectory maps" are classified as "noncyclic", "semicyclic", or
"cyclic", with examples of each given.
We find that radiative torques result in rapid grain alignment, even in the
absence of paramagnetic dissipation. It appears that radiative torques due to
starlight can account for the observed alignment of interstellar grains with
the Galactic magnetic field.Comment: 34 pages, 21 eps figures, uses aaspp4.sty . Submitted to Ap.
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