Browsing Physics and Astronomy by Type "Article"
Now showing items 41-60 of 82
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Neutron interferometer crystallographic imperfections and gravitationally induced quantum interference measurements
(American Physical Society, 2017-01-25)Dynamical diffraction leads to an interesting, unavoidable set of interference effects for neutron interferometers. This experiment studies the interference signal from two and three successive Bragg diffractions in the ... -
Neutron interferometric measurement of the scattering length difference between the triplet and singlet states of n-He-3
(American Physical Society, 2014-12-15)We report a determination of the n-He-3 scattering length difference = b = = b = 1 -b = 0 = [-5.411 = 0.031 (statistical) = 0.039 (systematic)] fm between the triplet and singlet states using a neutron interferometer. This ... -
Neutron Interferometry at the National Institute of Standards and Technology
(Hindawi, 2015)Neutron interferometry has proved to be a very precise technique for measuring the quantum mechanical phase of a neutron caused by a potential energy difference between two spatially separated neutron paths inside ... -
Neutron limit on the strongly-coupled chameleon field
(American Physical Society, 2016-03-11)The physical origin of the dark energy that causes the accelerated expansion rate of the Universe is one of the major open questions of cosmology. One set of theories postulates the existence of a self-interacting scalar ... -
Noise refocusing in a five-blade neutron interferometer
(AIP Publishing, 2017-08-07)We provide a quantum information description of a proposed five-blade neutron interferometer geometry and show that it is robust against low-frequency mechanical vibrations and dephasing due to the dynamical phase. The ... -
Opposing effects of cationic antimicrobial peptides and divalent cations on bacterial lipopolysaccharides
(American Physical Society, 2017-10-09)The permeability of the bacterial outer membrane, enclosing Gram-negative bacteria, depends on the interactions of the outer, lipopolysaccharide (LPS) layer, with surrounding ions and molecules. We present a coarse-grained ... -
Ordering and Reverse Ordering Mechanisms of Triblock Copolymers in the Presence of Solvent
(MDPI, 2009-02-27)Self-consistent field theory is used to study the self-assembly of a triblock copolymer melt. Two different external factors (temperature and solvent) are shown to affect the self-assembly. Either one or two-step self-assembly ... -
Ordering mechanisms in triblock copolymers
(American Physical Society, 2004)The ordering mechanisms for an ABC triblock copolymer system are studied using self-consistent field theory. We find a two-phase mechanism, similar to what has been suggested experimentally two-step mecha- nism. Analysis ... -
Origin of change in molecular-weight dependence for polymer surface tension
(APS publishing, 2008-09-30)Self-consistent-field theory is used to reproduce the behavior of polymer surface tension with molecular-weight for both lower and higher molecular-weight polymers. The change in behavior of the surface tension between ... -
Origins of Elastic Properties in Ordered Block Copolymer/Nanoparticle Composites
(American Chemical Society, 2004)We predict a diblock copolymer melt in the lamellar phase with added spherical nanoparticles that have an affinity for one block to have a lower tensile modulus than a pure diblock copolymer system. This weakening is due ... -
Origins of the failure of classical nucleation theory for nanocellular polymer foams
(RSC publishing, 2011-07-06)Relative nucleation rates for fluid bubbles of nanometre dimensions in polymer matrices are calculated using both classical nucleation theory and self-consistent field theory. An identical model is used for both calculations ... -
Particle Distributions in a Block Copolymer Nanocomposite
(American Chemical Society, 2008)Self-consistent-field theory is used to predict the center-of-mass distribution of spherical nanoparticles embedded in the lamellar phase of a diblock copolymer melt. The calculation is performed in the dilute limit, where ... -
Polymeric Foaming Predictions from the Sanchez-Lacombe Equation of State: Application to Polypropylene-Carbon Dioxide Mixtures
(American Physical Society, 2017)A simple off-lattice method of deriving the Sanchez-Lacombe equation of state is presented. The Sanchez-Lacombe equation of state for mixtures is shown to be thermodynamically inconsistent for all mixing rules in such a ... -
Predicting nonpolymeric materials structure with real-space self-consistent field theory
(APS publishing, 2006-02-17)Polymer self-consistent field theory of the Edwards-Helfand kind is the state-of-the-art method for predicting the morphologies of block copolymer materials. The methodology of block copolymer self-consistent field theory ... -
Predicting the Mesophases of Copolymer-Nanoparticle Composites
(American Association for the Advancement of Science, 2001)The interactions between mesophase-forming copolymers and nanoscopic par- ticles can lead to highly organized hybrid materials. The morphology of such composites depends not only on the characteristics of the copolymers, ... -
Predicting the phases of a two-dimensional hard-rod system with real-space self-consistent field theory
(APS publishing, 2006-10-16)Polymer self-consistent field theory numerical tools are applied to a two-dimensional hard-rod colloidal system. Rods are represented through an interaction site model density functional theory that is derived and expressed ... -
The PROSPECT reactor antineutrino experiment
(Elsevier, 2019-04-01)The Precision Reactor Oscillation and Spectrum Experiment, PROSPECT, is designed to make both a precise measurement of the antineutrino spectrum from a highly-enriched uranium reactor and to probe eV-scale sterile neutrinos ... -
Quantum correlations in a noisy neutron interferometer
(American Physical Society, 2014-09-15)We investigate quantum coherences in the presence of noise by entangling the spin and path degrees of freedom of the output neutron beam from a noisy three-blade perfect crystal neutron interferometer. We find that in the ... -
Quantum reference frames associated with non-compact groups: the case of translations and boosts, and the role of mass
(American Physical Society, 2016-03)Quantum communication without a shared reference frame or the construction of a relational quantum theory requires the notion of a quantum reference frame. We analyze aspects of quantum reference frames associated with ... -
Quantum-information approach to dynamical diffraction theory
(American Physical Society, 2016-12-08)We present a simplified model for dynamical diffraction of particles through a periodic thick perfect crystal based on repeated application of a coherent beam-splitting unitary at coarse-grained lattice sites. By demanding ...