4,707 research outputs found
The Characterization of Noncontextuality in the Framework of Generalized Probabilistic Theories
To make precise the sense in which the operational predictions of quantum
theory conflict with a classical worldview, it is necessary to articulate a
notion of classicality within an operational framework. A widely applicable
notion of classicality of this sort is whether or not the predictions of a
given operational theory can be explained by a generalized-noncontextual
ontological model. We here explore what notion of classicality this implies for
the generalized probabilistic theory (GPT) that arises from a given operational
theory, focusing on prepare-measure scenarios. We first show that, when mapping
an operational theory to a GPT by quotienting relative to operational
equivalences, the constraint of explainability by a generalized-noncontextual
ontological model is mapped to the constraint of explainability by an
ontological model. We then show that, under the additional assumption that the
ontic state space is of finite cardinality, this constraint on the GPT can be
expressed as a geometric condition which we term simplex-embeddability. Whereas
the traditional notion of classicality for a GPT is that its state space be a
simplex and its effect space be the dual of this simplex, simplex-embeddability
merely requires that its state space be embeddable in a simplex and its effect
space in the dual of that simplex. We argue that simplex-embeddability
constitutes an intuitive and freestanding notion of classicality for GPTs. Our
result also has applications to witnessing nonclassicality in prepare-measure
experiments.Comment: 5 pages + 5 page appendi
Draft Genome Sequence of Escherichia coli K-12 (ATCC 29425)
A draft genome sequence for Escherichia coli ATCC 29425 was investigated. The size of the genome was 4,608,319 bp, with an observed G+C content of 50.68%. This assembly consisted of 80 contigs, with an average coverage of 122.2Ă—, including one contig representative of the complete genome for the temperate phage P1
Quantifying Bell: the Resource Theory of Nonclassicality of Common-Cause Boxes
We take a resource-theoretic approach to the problem of quantifying
nonclassicality in Bell scenarios. The resources are conceptualized as
probabilistic processes from the setting variables to the outcome variables
having a particular causal structure, namely, one wherein the wings are only
connected by a common cause. We term them "common-cause boxes". We define the
distinction between classical and nonclassical resources in terms of whether or
not a classical causal model can explain the correlations. One can then
quantify the relative nonclassicality of resources by considering their
interconvertibility relative to the set of operations that can be implemented
using a classical common cause (which correspond to local operations and shared
randomness). We prove that the set of free operations forms a polytope, which
in turn allows us to derive an efficient algorithm for deciding whether one
resource can be converted to another. We moreover define two distinct monotones
with simple closed-form expressions in the two-party binary-setting
binary-outcome scenario, and use these to reveal various properties of the
pre-order of resources, including a lower bound on the cardinality of any
complete set of monotones. In particular, we show that the information
contained in the degrees of violation of facet-defining Bell inequalities is
not sufficient for quantifying nonclassicality, even though it is sufficient
for witnessing nonclassicality. Finally, we show that the continuous set of
convexly extremal quantumly realizable correlations are all at the top of the
pre-order of quantumly realizable correlations. In addition to providing new
insights on Bell nonclassicality, our work also sets the stage for quantifying
nonclassicality in more general causal networks.Comment: V4 changes: Accepted by Quantum, bibliography hyperlinks adjusted
according to journal policy. Slight reorganization of content in Section
Draft Genome Sequence of Escherichia coli K-12 (ATCC 10798)
Here, we present the draft genome sequence of Escherichia coli ATCC 10798. E. coli ATCC 10798 is a K-12 strain, one of the most well-studied model microorganisms. The size of the genome was 4,685,496 bp, with a G+C content of 50.70%. This assembly consists of 62 contigs and the F plasmid
Draft Genome Sequence of Micrococcus luteus (Schroeter) Cohn (ATCC 12698)
The actinobacterium Micrococcus luteus can be found in a wide variety of habitats. Here, we report the 2,411,958-bp draft genome sequence of the type strain M. leuteus (Schroeter) Cohn (ATCC 12698). Characteristic of this taxa, the genome sequence has a high G+C content, 73.14%
Draft Genome Sequence of Enterococcus faecalis ATCC BAA-2128
While a part of the native gut microflora, the Gram-positive bacterium Enterococcus faecalis can lead to serious infections elsewhere in the body. The draft genome of E. faecalis strain ATCC BAA-2128, isolated from piglet feces, was examined. This draft genome consists of 42 contigs, 12 of which exhibit homology to annotated plasmids
Contextuality without incompatibility
The existence of incompatible measurements is often believed to be a feature
of quantum theory which signals its inconsistency with any classical worldview.
To prove the failure of classicality in the sense of Kochen-Specker
noncontextuality, one does indeed require sets of incompatible measurements.
However, a more broadly applicable and more permissive notion of classicality
is the existence of a generalized-noncontextual ontological model. In
particular, this notion can imply constraints on the representation of outcomes
even within a single nonprojective measurement. We leverage this fact to
demonstrate that measurement incompatibility is neither necessary nor
sufficient for proofs of the failure of generalized noncontextuality.
Furthermore, we show that every proof of the failure of generalized
noncontextuality in a prepare-measure scenario can be converted into a proof of
the failure of generalized noncontextuality in a corresponding scenario with no
incompatible measurements
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