13,666 research outputs found
New Methods for Characterizing Phases of 2D Supersymmetric Gauge Theories
We study the physics of two-dimensional N=(2,2) gauged linear sigma models
(GLSMs) via the two-sphere partition function. We show that the classical phase
boundaries separating distinct GLSM phases, which are described by the
secondary fan construction for abelian GLSMs, are completely encoded in the
analytic structure of the partition function. The partition function of a
non-abelian GLSM can be obtained as a limit from an abelian theory; we utilize
this fact to show that the phases of non-abelian GLSMs can be obtained from the
secondary fan of the associated abelian GLSM. We prove that the partition
function of any abelian GLSM satisfies a set of linear differential equations;
these reduce to the familiar A-hypergeometric system of Gel'fand, Kapranov, and
Zelevinski for GLSMs describing complete intersections in toric varieties. We
develop a set of conditions that are necessary for a GLSM phase to admit an
interpretation as the low-energy limit of a non-linear sigma model with a
Calabi-Yau threefold target space. Through the application of these criteria we
discover a class of GLSMs with novel geometric phases corresponding to
Calabi-Yau manifolds that are branched double-covers of Fano threefolds. These
criteria provide a promising approach for constructing new Calabi-Yau
geometries.Comment: 25 pages + references, appendices. v2: references added, typos
corrected. v3: two small typos correcte
Comment on "Layering transition in confined molecular thin films: Nucleation and growth"
When fluid is confined between two molecularly smooth surfaces to a few
molecular diameters, it shows a large enhancement of its viscosity. From
experiments it seems clear that the fluid is squeezed out layer by layer. A
simple solution of the Stokes equation for quasi-two-dimensional confined flow,
with the assmption of layer-by-layer flow is found. The results presented here
correct those in Phys. Rev. B, 50, 5590 (1994), and show that both the
kinematic viscosity of the confined fluid and the coefficient of surface drag
can be obtained from the time dependence of the area squeezed out. Fitting our
solution to the available experimental data gives the value of viscosity which
is ~7 orders of magnitude higher than that in the bulk.Comment: 4 pages, 2 figure
Off-Diagonal Dark-Matter Phenomenology: Exploring Enhanced Complementarity Relations in Non-Minimal Dark Sectors
In most multi-component dark-matter scenarios, two classes of processes
generically contribute to event rates at experiments capable of probing the
nature of the dark sector. The first class consists of "diagonal" processes
involving only a single species of dark-matter particle -- processes analogous
to those which arise in single-component dark-matter scenarios. By contrast,
the second class consists of "off-diagonal" processes involving dark-matter
particles of different species. Such processes include inelastic scattering at
direct-detection experiments, asymmetric production at colliders, dark-matter
co-annihilation, and certain kinds of dark-matter decay. In typical
multi-component scenarios, the contributions from diagonal processes dominate
over those from off-diagonal processes. Unfortunately, this tends to mask those
features which are most sensitive to the multi-component nature of the dark
sector. In this paper, by contrast, we point out that there exist natural,
multi-component dark-sector scenarios in which the off-diagonal contributions
actually dominate over the diagonal. This then gives rise to a new, enhanced
picture of dark-matter complementarity. In this paper, we introduce a scenario
in which this situation arises and examine the enhanced picture of dark-matter
complementarity which emerges.Comment: 17 pages, LaTeX, 2 figures. Replaced to match published versio
A universal correction to higher spin entanglement entropy
We consider conformal field theories in 1+1 dimensions with W-algebra
symmetries, deformed by a chemical potential \mu for the spin-three current. We
show that the order \mu^2 correction to the Re'nyi and entanglement entropies
of a single interval in the deformed theory, on the infinite spatial line and
at finite temperature, is universal. The correction is completely determined by
the operator product expansion of two spin-three currents, and by the
expectation values of the stress tensor, its descendants and its composites,
evaluated on the n-sheeted Riemann surface branched along the interval. This
explains the recently found agreement of the order \mu^2 correction across
distinct free field CFTs and higher spin black hole solutions holographically
dual to CFTs with W-symmetry.Comment: Version accepted for publication as Rapid Communications in Phys.
Rev. D. Included an expanded discussion of the prescription used for contact
terms in relevant integrals; typos correcte
Posttraumatic Stress and Parenting Behaviors: The Mediating Role of Emotion Regulation
Maternal trauma has been linked with problematic parenting, including both harsh and permissive behaviors. However, little is known about mechanisms accounting for this association. The current study examined the potential impact of posttraumatic stress disorder (PTSD) and emotion regulation on dysfunctional parenting behaviors in a sample of community mothers. We hypothesized a mediation model wherein PTSD would be associated with dysfunctional parenting (i.e., lax and overreactive behaviors) indirectly through deficits in maternal emotion regulation. Seventy-eight community mothers of 18- to 36-month-old children were administered the Clinician Administered PTSD Scale for DSM-5 (CAPS-5) and 19 mothers met criteria for PTSD. Mothers also completed self-report measures of difficulties with emotion regulation and maternal laxness and overreactivity in parenting. Results revealed that emotion dysregulation fully mediated relations between PTSD status and lax (but not overreactive) parenting behaviors. Compared to mothers without PTSD, those with PTSD reported greater lax parenting behaviors indirectly through greater emotion dysregulation. Mothers with PTSD may struggle to parent assertively when trauma symptoms interfere with emotion regulation abilities. The current study highlights the need to design interventions focused on helping trauma-exposed mothers manage distress, ultimately aiming to enhance parenting effectiveness and improve child outcomes
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