1,447 research outputs found
Combined Modality Therapies for High-Risk Prostate Cancer: Narrative Review of Current Understanding and New Directions.
Despite the many prospective randomized trials that have been available in the past decade regarding the optimization of radiation, hormonal, and surgical therapies for high-risk prostate cancer (PCa), many questions remain. There is currently a lack of level I evidence regarding the relative efficacy of radical prostatectomy (RP) followed by adjuvant radiation compared to radiation therapy (RT) combined with androgen deprivation therapy (ADT) for high-risk PCa. Current retrospective series have also described an improvement in biochemical outcomes and PCa-specific mortality through the use of augmented radiation strategies incorporating brachytherapy. The relative efficacy of modern augmented RT compared to RP is still incompletely understood. We present a narrative review regarding recent advances in understanding regarding comparisons of overall and PCa-specific mortality measures among patients with high-risk PCa treated with either an RP/adjuvant RT or an RT/ADT approach. We give special consideration to recent trends toward the assembly of multi-institutional series targeted at providing high-quality data to minimize the effects of residual confounding. We also provide a narrative review of recent studies examining brachytherapy boost and systemic therapies, as well as an overview of currently planned and ongoing studies that will further elucidate strategies for treatment optimization over the next decade
Robust and Scalable Scheme to Generate Large-Scale Entanglement Webs
We propose a robust and scalable scheme to generate an -qubit state
among separated quantum nodes (cavity-QED systems) by using linear optics and
postselections. The present scheme inherits the robustness of the Barrett-Kok
scheme [Phys. Rev. A {\bf 71}, 060310(R) (2005)]. The scalability is also
ensured in the sense that an arbitrarily large -qubit state can be
generated with a quasi-polynomial overhead . The
process to breed the states, which we introduce to achieve the scalability,
is quite simple and efficient, and can be applied for other physical systems.Comment: 5 pages, 3 figure
On N=8 attractors
We derive and solve the black hole attractor conditions of N=8 supergravity
by finding the critical points of the corresponding black hole potential. This
is achieved by a simple generalization of the symplectic structure of the
special geometry to all extended supergravities with .
There are two solutions for regular black holes, one for 1/8 BPS ones and one
for the non-BPS. We discuss the solutions of the moduli at the horizon for BPS
attractors using N=2 language. An interpretation of some of these results in
N=2 STU black hole context helps to clarify the general features of the black
hole attractors.Comment: 15 page
Computational power of correlations
We study the intrinsic computational power of correlations exploited in
measurement-based quantum computation. By defining a general framework the
meaning of the computational power of correlations is made precise. This leads
to a notion of resource states for measurement-based \textit{classical}
computation. Surprisingly, the Greenberger-Horne-Zeilinger and
Clauser-Horne-Shimony-Holt problems emerge as optimal examples. Our work
exposes an intriguing relationship between the violation of local realistic
models and the computational power of entangled resource states.Comment: 4 pages, 2 figures, 2 tables, v2: introduction revised and title
changed to highlight generality of established framework and results, v3:
published version with additional table I
E_7 and the tripartite entanglement of seven qubits
In quantum information theory, it is well known that the tripartite
entanglement of three qubits is described by the group [SL(2,C)]^3 and that the
entanglement measure is given by Cayley's hyperdeterminant. This has provided
an analogy with certain N=2 supersymmetric black holes in string theory, whose
entropy is also given by the hyperdeterminant. In this paper, we extend the
analogy to N=8. We propose that a particular tripartite entanglement of seven
qubits, encoded in the Fano plane, is described by the exceptional group E_7(C)
and that the entanglement measure is given by Cartan's quartic E_7 invariant.Comment: Minor improvements. 15 page late
Proposed experiment for the quantum "Guess my number" protocol
An experimental realization of the entanglement-assisted "Guess my number"
protocol for the reduction of communication complexity, introduced by Steane
and van Dam, would require producing and detecting three-qubit GHZ states with
an efficiency eta > 0.70, which would require single photon detectors of
efficiency sigma > 0.89. We propose a modification of the protocol which can be
translated into a real experiment using present-day technology. In the proposed
experiment, the quantum reduction of the multi-party communication complexity
would require an efficiency eta > 0.05, achievable with detectors of sigma >
0.47, for four parties, and eta > 0.17 (sigma > 0.55) for three parties.Comment: REVTeX4, 4 pages, 1 figur
Hardy's argument and successive spin-s measurements
We consider a hidden-variable theoretic description of successive
measurements of non commuting spin observables on a input spin-s state. In this
scenario, the hidden-variable theory leads to a Hardy-type argument that
quantum predictions violate it. We show that the maximum probability of success
of Hardy's argument in quantum theory is , which is more
than in the spatial case.Comment: 7 page
Universal Measure of Entanglement
A general framework is developed for separating classical and quantum
correlations in a multipartite system. Entanglement is defined as the
difference in the correlation information encoded by the state of a system and
a suitably defined separable state with the same marginals. A generalization of
the Schmidt decomposition is developed to implement the separation of
correlations for any pure, multipartite state. The measure based on this
decomposition is a generalization of the entanglement of formation to
multipartite systems, provides an upper bound for the relative entropy of
entanglement, and is directly computable on pure states. The example of pure
three-qubit states is analyzed in detail, and a classification based on
minimal, four-term decompositions is developed.Comment: 4 page
Entanglement Purification of Any Stabilizer State
We present a method for multipartite entanglement purification of any
stabilizer state shared by several parties. In our protocol each party measures
the stabilizer operators of a quantum error-correcting code on his or her
qubits. The parties exchange their measurement results, detect or correct
errors, and decode the desired purified state. We give sufficient conditions on
the stabilizer codes that may be used in this procedure and find that Steane's
seven-qubit code is the smallest error-correcting code sufficient to purify any
stabilizer state. An error-detecting code that encodes two qubits in six can
also be used to purify any stabilizer state. We further specify which classes
of stabilizer codes can purify which classes of stabilizer states.Comment: 11 pages, 0 figures, comments welcome, submitting to Physical Review
A local hidden variable theory for the GHZ experiment
A recent analysis by de Barros and Suppes of experimentally realizable GHZ
correlations supports the conclusion that these correlations cannot be
explained by introducing local hidden variables. We show, nevertheless, that
their analysis does not exclude local hidden variable models in which the
inefficiency in the experiment is an effect not only of random errors in the
detector equipment, but is also the manifestation of a pre-set, hidden property
of the particles ("prism models"). Indeed, we present an explicit prism model
for the GHZ scenario; that is, a local hidden variable model entirely
compatible with recent GHZ experiments.Comment: 17 pages, LaTeX, 7 eps figures, computer demo:
http://hps.elte.hu/~leszabo/GHZ.html, an improper figure is replace
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