3,557 research outputs found
Complex aspects of gravity
This paper presents reflections on the validity of a series of mathematical
methods and technical assumptions that are encrusted in macrophysics (related
to gravitational interaction), that seem to have little or no physical
significance. It is interesting to inquire what a change can occur if one
removes some of the traditional assumptions.Comment: 10 page
Post-Election Audits: Restoring Trust in Elections
With the intention of assisting legislators, election officials and the public to make sense of recent literature on post-election audits and convert it into realistic audit practices, the Brennan Center and the Samuelson Law, Technology and Public Policy Clinic at Boalt Hall School of Law (University of California Berkeley) convened a blue ribbon panel (the "Audit Panel") of statisticians, voting experts, computer scientists and several of the nation's leading election officials. Following a review of the literature and extensive consultation with the Audit Panel, the Brennan Center and the Samuelson Clinic make several practical recommendations for improving post-election audits, regardless of the audit method that a jurisdiction ultimately decides to adopt
Variable Bias Coin Tossing
Alice is a charismatic quantum cryptographer who believes her parties are
unmissable; Bob is a (relatively) glamorous string theorist who believes he is
an indispensable guest. To prevent possibly traumatic collisions of
self-perception and reality, their social code requires that decisions about
invitation or acceptance be made via a cryptographically secure variable bias
coin toss (VBCT). This generates a shared random bit by the toss of a coin
whose bias is secretly chosen, within a stipulated range, by one of the
parties; the other party learns only the random bit. Thus one party can
secretly influence the outcome, while both can save face by blaming any
negative decisions on bad luck.
We describe here some cryptographic VBCT protocols whose security is
guaranteed by quantum theory and the impossibility of superluminal signalling,
setting our results in the context of a general discussion of secure two-party
computation. We also briefly discuss other cryptographic applications of VBCT.Comment: 14 pages, minor correction
Unification of Relativistic and Quantum Mechanics from Elementary Cycles Theory
In Elementary Cycles theory elementary quantum particles are consistently
described as the manifestation of ultra-fast relativistic spacetime cyclic
dynamics, classical in the essence. The peculiar relativistic geometrodynamics
of Elementary Cycles theory yields de facto a unification of ordinary
relativistic and quantum physics. In particular its classical-relativistic
cyclic dynamics reproduce exactly from classical physics first principles all
the fundamental aspects of Quantum Mechanics, such as all its axioms, the
Feynman path integral, the Dirac quantisation prescription (second
quantisation), quantum dynamics of statistical systems, non-relativistic
quantum mechanics, atomic physics, superconductivity, graphene physics and so
on. Furthermore the theory allows for the explicit derivation of gauge
interactions, without postulating gauge invariance, directly from relativistic
geometrodynamical transformations, in close analogy with the description of
gravitational interaction in general relativity. In this paper we summarise
some of the major achievements, rigorously proven also in several recent
peer-reviewed papers, of this innovative formulation of quantum particle
physics.Comment: 35 page
Optical Tracking and Spectral Characterization of Cubesats for Operational Missions
Orbital debris in low Earth orbit is of growing concern to operational satellites from the government and commercial sector. With an uptick in worldwide satellite launches and the growing adoption of the CubeSat standard, the number of small objects in orbit are increasing at a faster pace than ever. As a result, a cascading collision event seems inevitable in the near future.
The United States Strategic Command tracks and determines the orbit of resident space objects using a worldwide network of radar and optical sensors. However, in order to better protect space assets, there has been increased interest in not just knowing where a space object is, but what the object is. The optical and spectral characteristics of solar light reflected off of satellites or debris can provide information on the physical state or identity of the object. These same optical signatures can be used for mission support of operational satellite missions- down to satellites as small as CubeSats. Optical observation of CubeSats could provide independent monitoring of spin rate, deployable status, identification of individual CubeSats in a swarm, or possibly attitude information.
This thesis first introduces the reader to a review of available observation techniques followed by the basics of observational astronomy relevant to satellite tracking. The thesis then presents the OSCOM system- a system for Optical tracking and Spectral characterization of CubeSats for Operational Missions. OSCOM is a ground-based system capable of observing and characterizing small debris and CubeSats with commercially available optical telescopes and detectors. The system is just as applicable for larger satellites which have higher signal to noise ratio. The OSCOM system has been used to successfully collect time-series photometry of more than 60 unique satellites of all sizes. Selected photometry results are presented along with a discussion of the technical details required for optical observation of small satellites
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