10,199 research outputs found
A Transactional Analysis of Interaction Free Measurements
The transactional interpretation of quantum mechanics is applied to the
"interaction-free" measurement scenario of Elitzur and Vaidman and to the
Quantum Zeno Effect version of the measurement scenario by Kwiat, et al. It is
shown that the non-classical information provided by the measurement scheme is
supplied by the probing of the intervening object by incomplete offer and
confirmation waves that do not form complete transactions or lead to real
interactions.Comment: Accepted for publication in Foundations of Physics Letter
Entanglement genesis by ancilla-based parity measurement in 2D circuit QED
We present an indirect two-qubit parity meter in planar circuit quantum
electrodynamics, realized by discrete interaction with an ancilla and a
subsequent projective ancilla measurement with a dedicated, dispersively
coupled resonator. Quantum process tomography and successful entanglement by
measurement demonstrate that the meter is intrinsically quantum non-demolition.
Separate interaction and measurement steps allow commencing subsequent data
qubit operations in parallel with ancilla measurement, offering time savings
over continuous schemes.Comment: 5 pages, 4 figures; supplemental material with 5 figure
Chromaticity effects in microlensing by wormholes
Chromaticity effects introduced by the finite source size in microlensing
events by presumed natural wormholes are studied. It is shown that these
effects provide a specific signature that allow to discriminate between
ordinary and negative mass lenses through the spectral analysis of the
microlensing events. Both galactic and extragalactic situations are discussed.Comment: To appear in Modern Physics Letters A, 200
On the possibility of an astronomical detection of chromaticity effects in microlensing by wormhole-like objects
We study the colour changes induced by blending in a wormhole-like
microlensing scenario with extended sources. The results are compared with
those obtained for limb darkening. We assess the possibility of an actual
detection of the colour curve using the difference image analysis method.Comment: Accepted for publication in Modern Physics Letters A. 13 report
pages, 7 figure
Partial-measurement back-action and non-classical weak values in a superconducting circuit
We realize indirect partial measurement of a transmon qubit in circuit
quantum electrodynamics by interaction with an ancilla qubit and projective
ancilla measurement with a dedicated readout resonator. Accurate control of the
interaction and ancilla measurement basis allows tailoring the measurement
strength and operator. The tradeoff between measurement strength and qubit
back-action is characterized through the distortion of a qubit Rabi oscillation
imposed by ancilla measurement in different bases. Combining partial and
projective qubit measurements, we provide the solid-state demonstration of the
correspondence between a non-classical weak value and the violation of a
Leggett-Garg inequality.Comment: 5 pages, 4 figures, and Supplementary Information (8 figures
New CP-violation and preferred-frame tests with polarized electrons
We used a torsion pendulum containing polarized
electrons to search for CP-violating interactions between the pendulum's
electrons and unpolarized matter in the laboratory's surroundings or the sun,
and to test for preferred-frame effects that would precess the electrons about
a direction fixed in inertial space. We find and for AU. Our preferred-frame constraints, interpreted in
the Kosteleck\'y framework, set an upper limit on the parameter eV that should be compared to the benchmark
value eV.Comment: 4 figures, accepted for publication in Physical Review Letter
Multireference Methods are Realistic and Useful Tools for Modeling Catalysis
Highly correlated systems, in particular those that include transition metals, are ubiquitous in catalysis. The significant static correlation found in such systems is often poorly accounted for using Kohn Sham density functional theory methods, as they are single determinantal in nature. Applications to catalysis of more rigorous and appropriate multiconfigurational methods have been reported in select instances, but their use remains rare. We discuss obstacles that hinder the routine application of multireference (MR) wave function theoretical calculations to catalytic systems and the current state of the art with respect to removing those obstacles
Associated factors and consequences of risk of bias in randomized controlled trials of yoga: A systematic review
© 2015 Cramer et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Background: Bias in randomized controlled trials (RCTs) of complementary therapy interventions seems to be associated with specific factors and to potentially distort the studies' conclusions. This systematic review assessed associated factors of risk of bias and consequences for the studies' conclusions in RCTs of yoga as one of the most commonly used complementary therapies. Methods: Medline/PubMed, Scopus, IndMED and the Cochrane Library were searched through February 2014 for yoga RCTs. Risk of selection bias was assessed using the Cochrane tool and regressed to a) publication year; b) country of origin; c) journal type; and d) impact factor using multiple logistic regression analysis. Likewise, the authors' conclusions were regressed to risk of bias. Results: A total of 312 RCTs were included. Impact factor ranged from 0.0 to 39.2 (median = 1.3); 60 RCT (19.2%) had a low risk of selection bias, and 252 (80.8%) had a high or unclear risk of selection bias. Only publication year and impact factor significantly predicted low risk of bias; RCTs published after 2001 (adjusted odds ratio (OR) = 12.6; 95% confidence interval (CI) = 1.7, 94.0; p<0.001) and those published in journals with impact factor (adjusted OR = 2.6; 95%CI = 1.4, 4.9; p = 0.004) were more likely to have low risk of bias. The authors' conclusions were not associated with risk of bias. Conclusions: Risk of selection bias was generally high in RCTs of yoga; although the situation has improved since the publication of the revised CONSORT statement 2001. Pre-CONSORT RCTs and those published in journals without impact factor should be handled with increased care; although risk of bias is unlikely to distort the RCTs' conclusions
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