90,493 research outputs found
Named Models in Coalgebraic Hybrid Logic
Hybrid logic extends modal logic with support for reasoning about individual
states, designated by so-called nominals. We study hybrid logic in the broad
context of coalgebraic semantics, where Kripke frames are replaced with
coalgebras for a given functor, thus covering a wide range of reasoning
principles including, e.g., probabilistic, graded, default, or coalitional
operators. Specifically, we establish generic criteria for a given coalgebraic
hybrid logic to admit named canonical models, with ensuing completeness proofs
for pure extensions on the one hand, and for an extended hybrid language with
local binding on the other. We instantiate our framework with a number of
examples. Notably, we prove completeness of graded hybrid logic with local
binding
Entangled Bessel beams
Orbital angular momentum (OAM) entanglement is investigated in the
Bessel-Gauss (BG) basis. Having a readily adjustable radial scale, BG modes
provide a more favourable basis for OAM entanglement over Laguerre-Gaussian
(LG) modes. The OAM bandwidth in terms of BG modes can be increased by
selection of particular radial modes and leads to a flattening of the spectrum.
The flattening of the spectrum allows for higher entanglement. We demonstrate
increased entanglement in terms of BG modes by performing a Bell-type
experiment and violating the appropriate Clauser Horne Shimony Holt (CHSH)
inequality. In addition, we reconstruct the quantum state of BG modes entangled
in high-dimensions.Comment: 8 pages, 4 figure
Explicit Evidence Systems with Common Knowledge
Justification logics are epistemic logics that explicitly include
justifications for the agents' knowledge. We develop a multi-agent
justification logic with evidence terms for individual agents as well as for
common knowledge. We define a Kripke-style semantics that is similar to
Fitting's semantics for the Logic of Proofs LP. We show the soundness,
completeness, and finite model property of our multi-agent justification logic
with respect to this Kripke-style semantics. We demonstrate that our logic is a
conservative extension of Yavorskaya's minimal bimodal explicit evidence logic,
which is a two-agent version of LP. We discuss the relationship of our logic to
the multi-agent modal logic S4 with common knowledge. Finally, we give a brief
analysis of the coordinated attack problem in the newly developed language of
our logic
A Realist Interpretation of the Quantum Measurement Problem
A new, realist interpretation of the quantum measurement processes is given.
In this scenario a quantum measurement is a non-equilibrium phase transition in
a ``resonant cavity'' formed by the entire physical universe including all its
material and energy content. Both the amplitude and the phase of the quantum
mechanical wavefunction acquire substantial meaning in this picture, and the
probabilistic element is removed from the foundations of quantum mechanics, its
apparent presence in the quantum measurement process is viewed as a result of
the sensitive dependence on initial/boundary conditions of the non-equilibrium
phase transitions in a many degree-of-freedom system. The implications of
adopting this realist ontology to the clarification and resolution of lingering
issues in the foundations of quantum mechanics, such as wave-particle duality,
Heisenberg's uncertainty relation, Schrodinger's Cat paradox, first and higher
order coherence of photons and atoms, virtual particles, the existence of
commutation relations and quantized behavior, etc., are also presented.Comment: 8 pages, submiited to the Proceedings of the international conference
"Albert Einstein Century", held July 2005 in Paris, Franc
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