Ion structure in warm dense matter: benchmarking solutions of hypernetted-chain equations by first-principle simulations

We investigate the microscopic structure of strongly coupled ions in warm dense matter using ab initio simulations and hypernetted chain (HNC) equations. We demonstrate that an approximate treatment of quantum effects by weak pseudopotentials fails to describe the highly degenerate electrons in warm dense matter correctly. However, one-component HNC calculations for the ions agree well with first-principles simulations if a linearly screened Coulomb potential is used. These HNC results can be further improved by adding a short-range repulsion that accounts for bound electrons. Examples are given for recently studied light elements, lithium and beryllium, and for aluminum where the extra short-range repulsion is essential

Mapping a Homopolymer onto a Model Fluid

We describe a linear homopolymer using a Grand Canonical ensemble formalism, a statistical representation that is very convenient for formal manipulations. We investigate the properties of a system where only next neighbor interactions and an external, confining, field are present, and then show how a general pair interaction can be introduced perturbatively, making use of a Mayer expansion. Through a diagrammatic analysis, we shall show how constitutive equations derived for the polymeric system are equivalent to the Ornstein-Zernike and P.Y. equations for a simple fluid, and find the implications of such a mapping for the simple situation of Van der Waals mean field model for the fluid.Comment: 12 pages, 3 figure

Liquid Transport Due to Light Scattering

Using experiments and theory, we show that light scattering by inhomogeneities in the index of refraction of a fluid can drive a large-scale flow. The experiment uses a near-critical, phase-separated liquid, which experiences large fluctuations in its index of refraction. A laser beam traversing the liquid produces a large-scale deformation of the interface and can cause a liquid jet to form. We demonstrate that the deformation is produced by a scattering-induced flow by obtaining good agreements between the measured deformations and those calculated assuming this mechanism.Comment: 4 pages, 5 figures, submitted to Physical Review Letters v2: Edited based on comments from referee

Structure of strongly coupled, multi-component plasmas

We investigate the short-range structure in strongly coupled fluidlike plasmas using the hypernetted chain approach generalized to multicomponent systems. Good agreement with numerical simulations validates this method for the parameters considered. We found a strong mutual impact on the spatial arrangement for systems with multiple ion species which is most clearly pronounced in the static structure factor. Quantum pseudopotentials were used to mimic diffraction and exchange effects in dense electron-ion systems. We demonstrate that the different kinds of pseudopotentials proposed lead to large differences in both the pair distributions and structure factors. Large discrepancies were also found in the predicted ion feature of the x-ray scattering signal, illustrating the need for comparison with full quantum calculations or experimental verification

Quantum criticality around metal-insulator transitions of strongly correlated electrons

Quantum criticality of metal-insulator transitions in correlated electron systems is shownto belong to an unconventional universality class with violation of Ginzburg-Landau-Wilson(GLW) scheme formulated for symmetry breaking transitions. This unconventionality arises from an emergent character of the quantum critical point, which appears at the marginal point between the Ising-type symmetry breaking at nonzero temperatures and the topological transition of the Fermi surface at zero temperature. We show that Hartree-Fock approximations of an extended Hubbard model on square latticesare capable of such metal-insulator transitions with unusual criticality under a preexisting symmetry breaking. The obtained universality is consistent with the scaling theory formulated for Mott transition and with a number of numerical results beyond the mean-field level, implying that the preexisting symmetry breaking is not necessarily required for the emergence of this unconventional universality. Examinations of fluctuation effects indicate that the obtained critical exponents remain essentially exact beyond the mean-field level. Detailed analyses on the criticality, containing diverging carrier density fluctuations around the marginal quantum critical point, are presented from microscopic calculations and reveal the nature as quantum critical "opalescence". Analyses on crossovers between GLW type at nonzero temperature and topological type at zero temperature show that the critical exponents observed in (V,Cr)2O3 and kappa-ET-type organic conductor provide us with evidences for the existence of the present marginal quantum criticality.Comment: 24 pages, 19 figure

Caregiving for Older Adults with Obesity in the United States

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138397/1/jgs14918_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138397/2/jgs14918.pd

How do you define recovery? A qualitative study of patients with eating disorders, their parents, and clinicians

ObjectiveRecovery from an eating disorder (ED) may be defined differently by different stakeholders. We set out to understand the definition of ED recovery from the perspective of patients, their parents, and clinicians.MethodWe recruited patients with EDs (n = 24, ages 12–23 years) representing different diagnoses (anorexia nervosa n = 17, bulimia nervosa n = 4, binge‐ED n = 2, avoidant/restrictive food intake disorder n = 1), along with their parents (n = 20), dietitians (n = 11), therapists (n = 14), and primary care providers (n = 9) from three sites: Boston Children’s Hospital, University of Michigan C. S. Mott Children’s Hospital, and Penn State Hershey Children’s Hospital. In‐depth, semi‐structured, qualitative interviews explored participants’ definitions of recovery. Interviews were analyzed using inductive data‐driven thematic analysis. Statistical analyses followed to examine the distribution within each theme by respondent type.ResultsQualitative analysis resulted in the emergence of four overarching themes of ED recovery: (a) psychological well‐being, (b) eating‐related behaviors/attitudes, (c) physical markers, and (d) self‐acceptance of body image. Endorsement of themes two and four did not significantly differ between patients, parents, and clinicians. Clinicians were significantly more likely to endorse theme one (χ2 = 9.90, df = 2, p = .007, φc = 0.356) and theme three (χ2 = 6.42, df = 2, p = .04, φc = 0.287) than patients and parents.DiscussionOur study demonstrates overwhelming support for psychological markers as indicators of ED recovery by all three groups. Clinicians should remain open to additional markers of recovery such as body acceptance and eating‐related behaviors/emotions that may be of critical importance to patients and their caregivers.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156211/2/eat23294_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156211/1/eat23294.pd