32,561 research outputs found
Fuzziness at the horizon
We study the stability of the noncommutative Schwarzschild black hole
interior by analysing the propagation of a massless scalar field between the
two horizons. We show that the spacetime fuzziness triggered by the field
higher momenta can cure the classical exponential blue shift divergence,
suppressing the emergence of infinite energy density in a region nearby the
Cauchy horizon.Comment: 4 pages, 1 figure, new version matching that accepted for publicatio
Objective probability and quantum fuzziness
This paper offers a critique of the Bayesian interpretation of quantum
mechanics with particular focus on a paper by Caves, Fuchs, and Schack
containing a critique of the "objective preparations view" or OPV. It also aims
to carry the discussion beyond the hardened positions of Bayesians and
proponents of the OPV. Several claims made by Caves et al. are rebutted,
including the claim that different pure states may legitimately be assigned to
the same system at the same time, and the claim that the quantum nature of a
preparation device cannot legitimately be ignored. Both Bayesians and
proponents of the OPV regard the time dependence of a quantum state as the
continuous dependence on time of an evolving state of some kind. This leads to
a false dilemma: quantum states are either objective states of nature or
subjective states of belief. In reality they are neither. The present paper
views the aforesaid dependence as a dependence on the time of the measurement
to whose possible outcomes the quantum state serves to assign probabilities.
This makes it possible to recognize the full implications of the only testable
feature of the theory, viz., the probabilities it assigns to measurement
outcomes...Comment: 21 pages, no graphics, inspired by "Subjective probability and
quantum certainty" (quant-ph/0608190 v2
Quantum Mechanics as a Framework for Dealing with Uncertainty
Quantum uncertainty is described here in two guises: indeterminacy with its
concomitant indeterminism of measurement outcomes, and fuzziness, or
unsharpness. Both features were long seen as obstructions of experimental
possibilities that were available in the realm of classical physics. The birth
of quantum information science was due to the realization that such
obstructions can be turned into powerful resources. Here we review how the
utilization of quantum fuzziness makes room for a notion of approximate joint
measurement of noncommuting observables. We also show how from a classical
perspective quantum uncertainty is due to a limitation of measurability
reflected in a fuzzy event structure -- all quantum events are fundamentally
unsharp.Comment: Plenary Lecture, Central European Workshop on Quantum Optics, Turku
2009
Is the Fuzziness of GRB970228 constant?
In view of the data gathered in September 1997, we review the flux values
collected so far for the "fuzziness" seen in the optical counterpart of
GRB970228. Comparison between the ground based data collected in March and the
data of September 1997 suggests a fading of the fuzz. Given the diversity of
the data in hand, the magnitude of the effect and its significance are not easy
to quantify. Only new images, both from the ground and with the Space
Telescope, directly comparable to the old ones could settle this problem.Comment: 6 pages, Latex, 6 postscript figures, 1 postscript table Proceedings
of the 4th Huntsville Gammma-Ray Burst Symposiu
- …