15,172 research outputs found
Entanglement, intractability and no-signaling
We consider the problem of deriving the no-signaling condition from the
assumption that, as seen from a complexity theoretic perspective, the universe
is not an exponential place. A fact that disallows such a derivation is the
existence of {\em polynomial superluminal} gates, hypothetical primitive
operations that enable superluminal signaling but not the efficient solution of
intractable problems. It therefore follows, if this assumption is a basic
principle of physics, either that it must be supplemented with additional
assumptions to prohibit such gates, or, improbably, that no-signaling is not a
universal condition. Yet, a gate of this kind is possibly implicit, though not
recognized as such, in a decade-old quantum optical experiment involving
position-momentum entangled photons. Here we describe a feasible modified
version of the experiment that appears to explicitly demonstrate the action of
this gate. Some obvious counter-claims are shown to be invalid. We believe that
the unexpected possibility of polynomial superluminal operations arises because
some practically measured quantum optical quantities are not describable as
standard quantum mechanical observables.Comment: 17 pages, 2 figures (REVTeX 4
Neuroeconomics: infeasible and underdetermined
Advocates of neuroeconomics claim to offer the prospect of creating a “unified behavioral theory” by drawing upon the techniques of neuroscience and psychology and combining them with economic theory. Ostensibly, through the “direct measurement” of our thoughts, economics and social science will be “revolutionized.” Such claims have been subject to critique from mainstream and non-mainstream economists alike. Many of these criticisms relate to measurability, relevance, and coherence. In this article, we seek to contribute to this critical examination by investigating the potential of underdetermination, such as the statement that testing involves the conjunction of auxiliary assumptions, and that consequently it may not be possible to isolate the effect of any given hypothesis. We argue that neuroeconomics is especially sensitive to issues of underdetermination. Institutional economists should be cautious of neuroeconomists’ zeal as they appear to over-interpret experimental findings and, therefore, neuroeconomics may provide a false prospectus seeking to reinforce the nostrums of homo economicus
On palimpsests in neural memory: an information theory viewpoint
The finite capacity of neural memory and the
reconsolidation phenomenon suggest it is important to be able
to update stored information as in a palimpsest, where new
information overwrites old information. Moreover, changing
information in memory is metabolically costly. In this paper, we
suggest that information-theoretic approaches may inform the
fundamental limits in constructing such a memory system. In
particular, we define malleable coding, that considers not only
representation length but also ease of representation update,
thereby encouraging some form of recycling to convert an old
codeword into a new one. Malleability cost is the difficulty of
synchronizing compressed versions, and malleable codes are of
particular interest when representing information and modifying
the representation are both expensive. We examine the tradeoff
between compression efficiency and malleability cost, under a
malleability metric defined with respect to a string edit distance.
This introduces a metric topology to the compressed domain. We
characterize the exact set of achievable rates and malleability as
the solution of a subgraph isomorphism problem. This is all done
within the optimization approach to biology framework.Accepted manuscrip
Sense resolution properties of logical imaging
The evaluation of an implication by Imaging is a logical technique developed
in the framework of modal logic. Its interpretation in the context of a “possible
worlds” semantics is very appealing for IR. In 1994, Crestani and Van Rijsbergen
proposed an interpretation of Imaging in the context of IR based on the assumption
that “a term is a possibleworld”. This approach enables the exploitation of term–
term relationshipswhich are estimated using an information theoretic measure.
Recent analysis of the probability kinematics of Logical Imaging in IR have
suggested that this technique has some interesting sense resolution properties. In
this paper we will present this new line of research and we will relate it to more
classical research into word senses
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