12,441 research outputs found
Concerning resolvent estimates for simply connected manifolds of constant curvature
We prove families of uniform resolvent estimates for simply
connected manifolds of constant curvature (negative or positive) that imply the
earlier ones for Euclidean space of Kenig, Ruiz and the second author
\cite{KRS}. In the case of the sphere we take advantage of the fact that the
half-wave group of the natural shifted Laplacian is periodic. In the case of
hyperbolic space, the key ingredient is a natural variant of the Stein-Tomas
restriction theorem.Comment: 25 pages, 2 figure
How good are your testers? An assessment of testing ability
During our previous research conducted in the Sheffield Software Engineering Observatory [11], we found that test first programmers spent a higher percentage of their time testing than those testing after coding. However as the team allocation was based on subjects' academic records and their preference, it was unclear if they were simply better testers. Thus this paper proposes two questionnaires to assess the testing ability of subjects, in order to reveal the factors that contribute to the previous findings. Preliminary results show that the testing ability of subjects, as measured by the survey, varies based on their professional skill level
Boundary Conformal Field Theory and a Boundary Central Charge
We consider the structure of current and stress tensor two-point functions in
conformal field theory with a boundary. The main result of this paper is a
relation between a boundary central charge and the coefficient of a
displacement operator correlation function in the boundary limit. The boundary
central charge under consideration is the coefficient of the product of the
extrinsic curvature and the Weyl curvature in the conformal anomaly. Along the
way, we describe several auxiliary results. Three of the more notable are as
follows: (1) we give the bulk and boundary conformal blocks for the current
two-point function; (2) we show that the structure of these current and stress
tensor two-point functions is essentially universal for all free theories; (3)
we introduce a class of interacting conformal field theories with boundary
degrees of freedom, where the interactions are confined to the boundary. The
most interesting example we consider can be thought of as the infrared fixed
point of graphene. This particular interacting conformal model in four
dimensions provides a counterexample of a previously conjectured relation
between a boundary central charge and a bulk central charge. The model also
demonstrates that the boundary central charge can change in response to
marginal deformations.Comment: 75 pages, 4 figures; v2: references added. v3: comments on anomalous
dimension and references added. v4: minor corrections, published versio
A Psychology of Emotional Legal Decision Making: Revulsion and Saving Face in Legal Theory and Practice
Interface Conformal Anomalies
We consider two conformal field theories (CFTs) glued together
along a codimension one conformal interface. The conformal anomaly of such a
system contains both bulk and interface contributions. In a curved-space setup,
we compute the heat kernel coefficients and interface central charges in free
theories. The results are consistent with the known boundary CFT data via the
folding trick. In , two interface invariants generally allowed as
anomalies turn out to have vanishing interface charges. These missing
invariants are constructed from components with odd parity with respect to
flipping the orientation of the defect. We conjecture that all invariants
constructed from components with odd parity may have vanishing coefficient for
symmetric interfaces, even in the case of interacting interface CFT.Comment: 14 pp; v2: clarifications added, introduction expande
Physical Correlations of the Scatter between Galaxy Mass, Stellar Content, and Halo Mass
We use the UniverseMachine to analyze the source of scatter between the
central galaxy mass, the total stellar mass in the halo, and the dark matter
halo mass. We also propose a new halo mass estimator, the cen+N mass: the sum
of the stellar mass of the central and the N most massive satellites. We show
that, when real space positions are perfectly known, the cen+N mass has scatter
competitive with that of richness-based estimators. However, in redshift space,
the cen+N mass suffers less from projection effects in the UniverseMachine
model. The cen+N mass is therefore a viable low scatter halo mass estimator,
and should be considered an important tool to constrain cosmology with upcoming
spectroscopic data from DESI. We analyze the scatter in stellar mass at fixed
halo mass and show that the total stellar mass in a halo is uncorrelated with
secondary halo properties, but that the central stellar mass is a function of
both halo mass and halo age. This is because central galaxies in older halos
have had more time to grow via accretion. If the UniverseMachine model is
correct, accurate galaxy-halo modeling of mass selected samples therefore needs
to consider halo age in addition to mass.Comment: 13 pages, 11 figures, submitted to MNRA
Superconformal Models for Graphene and Boundary Central Charges
In the context of boundary conformal field theory, we investigate whether the
boundary trace anomaly can depend on marginal directions in the presence of
supersymmetry. Recently, it was found that a graphene-like non-supersymmetric
conformal field theory with a four-dimensional bulk photon and a
three-dimensional boundary electron has two boundary central charges that
depend on an exactly marginal direction, namely the gauge coupling. In this
work, we supersymmetrize this theory, paying special attention to the boundary
terms required by supersymmetry. We study models with 4, 8, and 16 Poincar\'e
supercharges in the bulk, half of which are broken by the boundary. In all
cases, we find that at all orders in perturbation theory, the gauge coupling is
not renormalized, providing strong evidence that these theories are boundary
conformal field theories. Moreover, the boundary central charges depend on the
coupling. One possible exception to this dependence on marginal directions is
that the difference between the two charges is coupling independent at one-loop
in the maximally supersymmetric case. In our analysis, a possible boundary
Chern-Simons term is incorporated by a bulk -term.Comment: 47 pages; v2: footnotes and references adde
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