A mean field approach for string condensed states

We describe a mean field technique for quantum string (or dimer) models. Unlike traditional mean field approaches, the method is general enough to include string condensed phases in addition to the usual symmetry breaking phases. Thus, it can be used to study phases and phases transitions beyond Landau's symmetry breaking paradigm. We demonstrate the technique with a simple example: the spin-1 XXZ model on the Kagome lattice. The mean field calculation predicts a number of phases and phase transitions, including a z=2 deconfined quantum critical point.Comment: 10 pages + appendix, 15 figure

Casimir repulsion between metallic objects in vacuum

We give an example of a geometry in which two metallic objects in vacuum experience a repulsive Casimir force. The geometry consists of an elongated metal particle centered above a metal plate with a hole. We prove that this geometry has a repulsive regime using a symmetry argument and confirm it with numerical calculations for both perfect and realistic metals. The system does not support stable levitation, as the particle is unstable to displacements away from the symmetry axis.Comment: 4 pages, 4 figures; added references, replaced Fig.

Weight-Related Psychological Inflexibility as a Mediator Between Weight Self-Stigma and Health-Related Outcomes

Weight self-stigma, the internalization of negative societal stereotypes, is a problem amongst populations with high weight. Weight self-stigma is associated with psychological inflexibility and maladaptive health-related behaviors. In this study, we explore how weight-related psychological inflexibility may influence weight self-stigma and health-related outcomes in 79 adults with high weight. Participants were primarily white (92.4%) and female (82.3%), with an average age of 39.56 and average body mass index of 33.78. The present study uses baseline, self-report data from a larger trial. Results indicate that weight self-stigma was negatively correlated with maladaptive eating behaviors, weight, and mental health. Weight-related psychological inflexibility was found as a significant mediator for the relationship between weight self-stigma and emotional eating, sedentary behavior, and mental health. Weight-related psychological inflexibility did not mediate the relationships between weight self-stigma and other eating measures and physical activity. These results support targeting weight-related psychological inflexibility and weight self-stigma in interventions

Evaluating the Open and Engaged Components of Acceptance and Commitment Therapy in an Online Self-Guided Website: Results From a Pilot Trial

Online acceptance and commitment therapy (ACT) is promising for treating a range of psychological problems. Component research can further clarify which components are needed for optimal outcomes in what contexts. Online platforms provide a highly controlled format for such research. In this pilot trial, 55 adults were randomized to: ACT-Open (i.e., acceptance, defusion components), ACT-Engaged (i.e., values, committed action), or ACT-Combined (i.e., acceptance, defusion, values, committed action). Each condition was 12 sessions over six weeks, with assessments at baseline, posttreatment, and four-week follow-up. ACT-Open, ACT-Engaged, and ACT-Combined all significantly improved from pre- to post-treatment on mental health, psychosocial functioning, and components of psychological flexibility. Compared to ACT-Combined, ACT-Open improved less on psychosocial functioning at posttreatment, and ACT-Engaged worsened on functioning at follow-up. The platform was acceptable with high satisfaction ratings. Results support the feasibility of conducting online ACT component research, which will be tested in a fully powered non-inferiority trial

The Potential Benefits of Flexibility for Dissemination and Implementation: Acceptance and Commitment Therapy as an Example

Our commentary on the article by Fixsen and Blase (2018) highlights some of the converging and diverging strategies between the Teaching-Family Model (TFM) and the dissemination and implementation of acceptance and commitment therapy (ACT). We focus primarily on the potential benefits of flexibility in areas including theory, methodology, and intervention protocols. Examples include the use of middle level terms, randomized controlled trial methods, protocols focused more on function than specific topography, and an open, collaborative approach to dissemination. We also note how this broader set of strategies can be made coherent and progressive through a careful connection back to contextual behavioral science as an underlying scientific strategy and its associated philosophy of science. We hope this approach contributes to an ongoing conversation on potentially useful strategies for dissemination and implementation

Is the electrostatic force between a point charge and a neutral metallic object always attractive?

We give an example of a geometry in which the electrostatic force between a point charge and a neutral metallic object is repulsive. The example consists of a point charge centered above a thin metallic hemisphere, positioned concave up. We show that this geometry has a repulsive regime using both a simple analytical argument and an exact calculation for an analogous two-dimensional geometry. Analogues of this geometry-induced repulsion can appear in many other contexts, including Casimir systems.Comment: 7 pages, 7 figure

Discretization Dependence of Criticality in Model Fluids: a Hard-core Electrolyte

Grand canonical simulations at various levels, $\zeta=5$-20, of fine- lattice discretization are reported for the near-critical 1:1 hard-core electrolyte or RPM. With the aid of finite-size scaling analyses it is shown convincingly that, contrary to recent suggestions, the universal critical behavior is independent of $\zeta$ (\grtsim 4); thus the continuum $(\zeta\to\infty)$ RPM exhibits Ising-type (as against classical, SAW, XY, etc.) criticality. A general consideration of lattice discretization provides effective extrapolation of the {\em intrinsically} erratic $\zeta$-dependence, yielding (\Tc^ {\ast},\rhoc^{\ast})\simeq (0.0493_{3},0.075) for the $\zeta=\infty$ RPM.Comment: 4 pages including 4 figure

Is Perfectionism Always Unhealthy? Examining the Moderating Effects of Psychological Flexibility and Self-Compassion

Objectives: Perfectionism is generally associated with worse mental health outcomes, though evidence suggests elements of it might be helpful. In light of these findings, we examined whether psychological skills like psychological flexibility and self-compassion moderated the relationship between perfectionism and wellbeing (i.e., quality of life, symptom impairment, and psychological distress). Methods: Undergraduate students (N= 677) completed self-report measures. Results: A latent profile analysis identified three perfectionism groups (low, average, high) based on four perfectionism subscales: concern over mistakes, need for approval, rumination, and striving for excellence. Generally, we found that psychological flexibility and/or self-compassion buffered the impact of average and high perfectionism on quality of life and symptom impairment. Conclusion: Our results support the utility of practicing psychological flexibility and/or self-compassion for people with average and high levels of perfectionism. Limitations include using a cross-sectional design and non-clinical sample