266 research outputs found
Coulomb force effects in low-energy -deuteron scattering
The -proton Coulomb interaction is included in the description of
-deuteron scattering using the screening and renormalization approach
in the framework of momentum-space three-particle equations. The technical
reliability of the method is demonstrated. Large Coulomb-force effects are
found.Comment: To be published in Phys. Rev.
New calculation schemes for proton-deuteron scattering including the Coulomb interaction
The Coulomb interaction between the protons is included in the description of
proton-deuteron scattering using the screening and renormalization approach in
the framework of momentum-space integral equations. Two new calculational
schemes are presented that confirm the reliability of the perturbative approach
for treating the screened Coulomb interaction in high partial waves, used by us
in earlier works.Comment: To be published in Phys. Rev.
Three-body description of direct nuclear reactions: Comparison with the continuum discretized coupled channels method
The continuum discretized coupled channels (CDCC) method is compared to the
exact solution of the three-body Faddeev equations in momentum space. We
present results for: i) elastic and breakup observables of d-12C at E_d=56 MeV,
ii) elastic scattering of d-58Ni at E_d=80 MeV, and iii) elastic, breakup and
transfer observables for 11Be+p at E_{11Be}/A=38.4 MeV. Our comparative studies
show that, in the first two cases, the CDCC method is a good approximation to
the full three-body Faddeev solution, but for the 11Be exotic nucleus,
depending on the observable or the kinematic regime, it may miss out some of
the dynamic three-body effects that appear through the explicit coupling to the
transfer channel.Comment: 12 pages, 10 figures, accepted for publication in Physical Review
Modeling Pitch Trajectories in Fastpitch Softball
The fourth-order Runge–Kutta method is used to numerically integrate the equations of motion for a fastpitch softball pitch and to create a model from which the trajectories of drop balls, rise balls and curve balls can be computed and displayed. By requiring these pitches to pass through the strike zone, and by assuming specific values for the initial speed, launch angle and height of each pitch, an upper limit on the lift coefficient can be predicted which agrees with experimental data. This approach also predicts the launch angles necessary to put rise balls, drop balls and curve balls in the strike zone, as well as a value of the drag coefficient that agrees with experimental data. Finally, Adair’s analysis of a batter’s swing is used to compare pitches that look similar to a batter starting her swing, yet which diverge before reaching the home plate, to predict when she is likely to miss or foul the ball
Are (pre)adolescents differentially susceptible to experimentally manipulated peer acceptance and rejection? A vignette-based experiment
The differential susceptibility model proposes that some children are more susceptible to both positive and negative peer relationships than others. However, experimental evidence supporting such a proposition is relatively scarce. The current experiment aimed to help address this gap, investigating whether Chinese (pre)adolescents who have higher levels of general sensitivity to the environment (i.e., higher levels of sensory processing sensitivity [SPS]) would be more strongly affected by peer acceptance and rejection. (Pre)adolescents aged 8.75–15.17 (N = 1,207, Mage = 11.19 years, 59.7% boys) randomly received four hypothetical vignettes describing either peer acceptance or peer rejection. Before and after this manipulation, they reported on their positive and negative mood. We assessed (pre)adolescents’ SPS using (pre)adolescent self-reports, as well as caregiver reports for a subset of (pre)adolescents (n = 480). Results supported differential susceptibility to peer rejection and acceptance for self-reported SPS, but not caregiver-reported SPS. (Pre)adolescents with higher levels of self-reported SPS not only had stronger increases in positive mood upon peer acceptance (susceptible “for better”; β = .09, p = .001) but also stronger increases in negative mood upon peer rejection (susceptible “for worse”; β = .09, p = .023). These findings illustrate the short-term dynamics that may underlie differences in children’s long-term susceptibility to acceptance or rejection by peers
Benchmark calculation for proton-deuteron elastic scattering observables including Coulomb
Two independent calculations of proton-deuteron elastic scattering
observables including Coulomb repulsion between the two protons are compared in
the proton lab energy region between 3 MeV and 65 MeV. The hadron dynamics is
based on the purely nucleonic charge-dependent AV18 potential. Calculations are
done both in coordinate space and momentum space. The coordinate-space
calculations are based on a variational solution of the three-body
Schr\"odinger equation using a correlated hyperspherical expansion for the wave
function. The momentum-space calculations proceed via the solution of the
Alt-Grassberger-Sandhas equation using the screened Coulomb potential and the
renormalization approach. Both methods agree within 1% on all observables,
showing the reliability of both numerical techniques in that energy domain. At
energies below three-body breakup threshold the coordinate-space method remains
favored whereas at energies higher than 65 MeV the momentum-space approach
seems to be more efficient.Comment: Submitted to Phys. Rev.
Psychometric properties of the Chinese version of the Highly Sensitive Child scale across age groups, gender, and informants
Sensory Processing Sensitivity (SPS) is theorized to be a fundamental trait capturing children’s general sensitivity to the environment. Yet, scientific knowledge of SPS is mostly based on findings from Western cultures and few translated measures exist to assess children’s SPS outside of Western countries. Therefore, we developed the Chinese Highly Sensitive Child (HSC) scale. In Study 1, we investigated the scale’s psychometric properties for both self-reports (N = 2925, Mage = 11.74 years, 43.3% girls) and caregiver reports (n = 460, Mchild age = 9.02 years, 44.0% girls). Findings replicated most psychometric properties found in international studies including: (a) a bifactor structure with one general sensitivity component and three specific components, (b) acceptable internal consistency of the total scale (although not for self-report of elementary school children, and not for the subscales), and (c) at least partial invariance across age groups, gender, and informants. In Study 2, we investigated convergent validity with related temperament and personality measures using self-reports from both elementary school children (n = 845, Mage = 9.71 years, 41.9% girls) and middle school children (n = 563, Mage = 13.17 years, 43.2% girls). Findings replicated bivariate associations found in Western studies: Ease of Excitation (EOE) was associated with more positive traits, whereas Aesthetic Sensitivity (AES) was associated with more negative traits, suggesting that EOE and AES may capture the “dark” and “bright side” of sensitivity, respectively. We hope that our studies help spur research on SPS across western and Chinese cultures
Noncommutative Quantum Mechanics and rotating frames
We study the effect of noncommutativity of space on the physics of a quantum
interferometer located in a rotating disk in a gauge field background. To this
end, we develop a path-integral approach which allows defining an effective
action from which relevant physical quantities can be computed as in the usual
commutative case. For the specific case of a constant magnetic field, we are
able to compute, exactly, the noncommutative Lagrangian and the associated
shift on the interference pattern for any value of .Comment: 17 pages, presentation improved, references added. To appear in
Physical Review
Local Entanglement Entropy and Mutual Information across the Mott Transition in the Two-Dimensional Hubbard Model
Entanglement and information are powerful lenses to probe phases transitions
in many-body systems. Motivated by recent cold atom experiments, which are now
able to measure the corresponding information-theoretic quantities, we study
the Mott transition in the half-filled two-dimensional Hubbard model using
cellular dynamical mean-field theory, and focus on two key measures of quantum
correlations: entanglement entropy and mutual information. We show that they
detect the first-order nature of the transition, the universality class of the
endpoint, and the crossover emanating from the endpoint.Comment: 6 pages, 3 figure
Thermodynamic and information-theoretic description of the Mott transition in the two-dimensional Hubbard model
At the Mott transition, electron-electron interaction changes a metal, in
which electrons are itinerant, to an insulator, in which electrons are
localized. This phenomenon is central to quantum materials. Here we contribute
to its understanding by studying the two-dimensional Hubbard model at finite
temperature with plaquette cellular dynamical mean-field theory. We provide an
exhaustive thermodynamic description of the correlation-driven Mott transition
of the half-filled model by calculating pressure, charge compressibility,
entropy, kinetic energy, potential energy and free energy across the
first-order Mott transition and its high-temperature crossover (Widom line).
The entropy is extracted from the Gibbs-Duhem relation and shows complex
behavior near the transition, marked by discontinuous jumps at the first-order
boundary, singular behavior at the Mott endpoint and inflections marking sharp
variations in the supercritical region. The free energy allows us to identify
the thermodynamic phase boundary, to discuss phases stability and
metastability, and to touch upon nucleation and spinodal decomposition
mechanisms for the transition. We complement this thermodynamic description of
the Mott transition by an information-theoretic description. We achieve this by
calculating the local entropy, which is a measure of entanglement, and the
single-site total mutual information, which quantifies quantum and classical
correlations. These information-theoretic measures exhibit characteristic
behaviors that allow us to identify the first-order coexistence regions, the
Mott critical endpoint and the crossovers along the Widom line in the
supercritical region.Comment: 22 pages, 15 figure
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