24,314 research outputs found
State Vector Reduction as a Shadow of a Noncommutative Dynamics
A model, based on a noncommutative geometry, unifying general relativity with
quantum mechanics, is further develped. It is shown that the dynamics in this
model can be described in terms of one-parameter groups of random operators. It
is striking that the noncommutative counterparts of the concept of state and
that of probability measure coincide. We also demonstrate that the equation
describing noncommutative dynamics in the quantum gravitational approximation
gives the standard unitary evolution of observables, and in the "space-time
limit" it leads to the state vector reduction. The cases of the spin and
position operators are discussed in details.Comment: 20 pages, LaTex, no figure
Noncommutative Dynamics of Random Operators
We continue our program of unifying general relativity and quantum mechanics
in terms of a noncommutative algebra on a transformation groupoid
where is the total space of a principal fibre bundle
over spacetime, and a suitable group acting on . We show that
every defines a random operator, and we study the dynamics of
such operators. In the noncommutative regime, there is no usual time but, on
the strength of the Tomita-Takesaki theorem, there exists a one-parameter group
of automorphisms of the algebra which can be used to define a state
dependent dynamics; i.e., the pair , where is a state
on , is a ``dynamic object''. Only if certain additional conditions
are satisfied, the Connes-Nikodym-Radon theorem can be applied and the
dependence on disappears. In these cases, the usual unitary quantum
mechanical evolution is recovered. We also notice that the same pair defines the so-called free probability calculus, as developed by
Voiculescu and others, with the state playing the role of the
noncommutative probability measure. This shows that in the noncommutative
regime dynamics and probability are unified. This also explains probabilistic
properties of the usual quantum mechanics.Comment: 13 pages, LaTe
SU(3) Lattice Gauge Theory in the Fundamental--Adjoint Plane and Scaling Along the Wilson Axis
We present further evidence for the bulk nature of the phase transition line
in the fundamental--adjoint action plane of SU(3) lattice gauge theory.
Computing the string tension and some glueball masses along the thermal phase
transition line of finite temperature systems with , which was found to
join onto the bulk transition line at its endpoint, we find that the ratio
remains approximately constant. However, the mass of the
glueball decreases as the endpoint of the bulk transition line is
approached, while the other glueball masses appear unchanged. This is
consistent with the notion that the bulk transition line ends in a critical
endpoint, with the continuum limit there being a theory with a
diverging correlation length only in the channel. We comment on the
implications for the scaling behavior along the fundamental or Wilson axis.Comment: 10 pages. Plain LaTeX file. 4 postscript figures added in a separate
fil
Conceptual Unification of Gravity and Quanta
We present a model unifying general relativity and quantum mechanics. The
model is based on the (noncommutative) algebra \mbox{{\cal A}} on the groupoid
\Gamma = E \times G where E is the total space of the frame bundle over
spacetime, and G the Lorentz group. The differential geometry, based on
derivations of \mbox{{\cal A}}, is constructed. The eigenvalue equation for the
Einstein operator plays the role of the generalized Einstein's equation. The
algebra \mbox{{\cal A}}, when suitably represented in a bundle of Hilbert
spaces, is a von Neumann algebra \mathcal{M} of random operators representing
the quantum sector of the model. The Tomita-Takesaki theorem allows us to
define the dynamics of random operators which depends on the state \phi . The
same state defines the noncommutative probability measure (in the sense of
Voiculescu's free probability theory). Moreover, the state \phi satisfies the
Kubo-Martin-Schwinger (KMS) condition, and can be interpreted as describing a
generalized equilibrium state. By suitably averaging elements of the algebra
\mbox{{\cal A}}, one recovers the standard geometry of spacetime. We show that
any act of measurement, performed at a given spacetime point, makes the model
to collapse to the standard quantum mechanics (on the group G). As an example
we compute the noncommutative version of the closed Friedman world model.
Generalized eigenvalues of the Einstein operator produce the correct components
of the energy-momentum tensor. Dynamics of random operators does not ``feel''
singularities.Comment: 28 LaTex pages. Substantially enlarged version. Improved definition
of generalized Einstein's field equation
Group invariant inferred distributions via noncommutative probability
One may consider three types of statistical inference: Bayesian, frequentist,
and group invariance-based. The focus here is on the last method. We consider
the Poisson and binomial distributions in detail to illustrate a group
invariance method for constructing inferred distributions on parameter spaces
given observed results. These inferred distributions are obtained without using
Bayes' method and in particular without using a joint distribution of random
variable and parameter. In the Poisson and binomial cases, the final formulas
for inferred distributions coincide with the formulas for Bayes posteriors with
uniform priors.Comment: Published at http://dx.doi.org/10.1214/074921706000000563 in the IMS
Lecture Notes--Monograph Series
(http://www.imstat.org/publications/lecnotes.htm) by the Institute of
Mathematical Statistics (http://www.imstat.org
SVIM: Structural Variant Identification using Mapped Long Reads
Motivation: Structural variants are defined as genomic variants larger than 50bp. They have been shown to affect more bases in any given genome than SNPs or small indels. Additionally, they have great impact on human phenotype and diversity and have been linked to numerous diseases. Due to their size and association with repeats, they are difficult to detect by shotgun sequencing, especially when based on short reads. Long read, single molecule sequencing technologies like those offered by Pacific Biosciences or Oxford Nanopore Technologies produce reads with a length of several thousand base pairs. Despite the higher error rate and sequencing cost, long read sequencing offers many advantages for the detection of structural variants. Yet, available software tools still do not fully exploit the possibilities. Results: We present SVIM, a tool for the sensitive detection and precise characterization of structural variants from long read data. SVIM consists of three components for the collection, clustering and combination of structural variant signatures from read alignments. It discriminates five different variant classes including similar types, such as tandem and interspersed duplications and novel element insertions. SVIM is unique in its capability of extracting both the genomic origin and destination of duplications. It compares favorably with existing tools in evaluations on simulated data and real datasets from PacBio and Nanopore sequencing machines. Availability and implementation: The source code and executables of SVIM are available on Github: github.com/eldariont/svim. SVIM has been implemented in Python 3 and published on bioconda and the Python Package Index. Supplementary information: Supplementary data are available at Bioinformatics online
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