555 research outputs found
Do You Have A Boyfriend Yet?
“Do you have a boyfriend yet?”
That was the question that haunted me for most of my teenage years, the one I knew I would be asked at each family event and have to answer as nonchalantly as I could, “No, not yet,” without letting anyone know how embarrassed I felt. The feelings of anguish and anxiety continued in games of “Never Have I Ever,” going around the table with a group of less-than-close girlfriends sharing some of our first or best romantic experiences, so grateful that I had those one or two experiences that “kind of counted but maybe not so I really hope no one asks me to go into detail.” [excerpt
The Casimir Effect for Generalized Piston Geometries
In this paper we study the Casimir energy and force for generalized pistons
constructed from warped product manifolds of the type where
is an interval of the real line and is a smooth compact
Riemannian manifold either with or without boundary. The piston geometry is
obtained by dividing the warped product manifold into two regions separated by
the cross section positioned at . By exploiting zeta function
regularization techniques we provide formulas for the Casimir energy and force
involving the arbitrary warping function and base manifold .Comment: 16 pages, LaTeX. To appear in the proceedings of the Conference on
Quantum Field Theory Under the Influence of External Conditions (QFEXT11).
Benasque, Spain, September 18-24, 201
The Spectral Zeta Function for Laplace Operators on Warped Product Manifolds of the type
In this work we study the spectral zeta function associated with the Laplace
operator acting on scalar functions defined on a warped product of manifolds of
the type where is an interval of the real line and is a
compact, -dimensional Riemannian manifold either with or without boundary.
Starting from an integral representation of the spectral zeta function, we find
its analytic continuation by exploiting the WKB asymptotic expansion of the
eigenfunctions of the Laplace operator on for which a detailed analysis is
presented. We apply the obtained results to the explicit computation of the
zeta regularized functional determinant and the coefficients of the heat kernel
asymptotic expansion.Comment: 29 pages, LaTe
Heat Kernel Coefficients for Laplace Operators on the Spherical Suspension
In this paper we compute the coefficients of the heat kernel asymptotic
expansion for Laplace operators acting on scalar functions defined on the so
called spherical suspension (or Riemann cap) subjected to Dirichlet boundary
conditions. By utilizing a contour integral representation of the spectral zeta
function for the Laplacian on the spherical suspension we find its analytic
continuation in the complex plane and its associated meromorphic structure.
Thanks to the well known relation between the zeta function and the heat kernel
obtainable via Mellin transform we compute the coefficients of the asymptotic
expansion in arbitrary dimensions. The particular case of a -dimensional
sphere as the base manifold is studied as well and the first few heat kernel
coefficients are given explicitly.Comment: 26 Pages, 1 Figur
Zeta Determinant for Laplace Operators on Riemann Caps
The goal of this paper is to compute the zeta function determinant for the
massive Laplacian on Riemann caps (or spherical suspensions). These manifolds
are defined as compact and boundaryless dimensional manifolds deformed by a
singular Riemannian structure. The deformed spheres, considered previously in
the literature, belong to this class. After presenting the geometry and
discussing the spectrum of the Laplacian, we illustrate a method to compute its
zeta regularized determinant. The special case of the deformed sphere is
recovered as a limit of our general formulas.Comment: 19 pages, 1 figur
Noncommutative Einstein Equations
We study a noncommutative deformation of general relativity where the
gravitational field is described by a matrix-valued symmetric two-tensor field.
The equations of motion are derived in the framework of this new theory by
varying a diffeomorphisms and gauge invariant action constructed by using a
matrix-valued scalar curvature. Interestingly the genuine noncommutative part
of the dynamical equations is described only in terms of a particular tensor
density that vanishes identically in the commutative limit. A noncommutative
generalization of the energy-momentum tensor for the matter field is studied as
well.Comment: 17 Pages, LaTeX, reference adde
Small Mass Expansion of Functional Determinants on the Generalized Cone
In this paper we compute the small mass expansion for the functional
determinant of a scalar Laplacian defined on the bounded, generalized cone. In
the framework of zeta function regularization, we obtain an expression for the
functional determinant valid in any dimension for both Dirichlet and Robin
boundary conditions in terms of the spectral zeta function of the base
manifold. Moreover, as a particular case, we specify the base to be a
-dimensional sphere and present explicit results for .Comment: LaTeX, 23 page
Results of the fifth international spectroradiometer comparison for improved solar spectral irradiance measurements and related impact on reference solar cell calibration
This paper reports on the results of the fifth spectral irradiance measurement intercomparison and the impact these results have on the spread of spectral mismatch calculations in the outdoor characterization of reference solar cell and photovoltaic (PV) devices. Ten laboratories and commercial partners with their own instruments were involved in the comparison. Solar spectral irradiance in clear sky condition was measured with both fast fixed and slow rotating grating spectroradiometers. This paper describes the intercomparison campaign, describes different statistical analysis used on acquired data, reports on the results, and analyzes the impact these results would have on the primary calibration of a c-Si PV reference cell under natural sunlight
Impact of advanced paternal age on the intracytoplasmic sperm injection (ICSI) outcomes in donor egg cycles
Non-commutative Corrections in Spectral Matrix Gravity
We study a non-commutative deformation of general relativity based on
spectral invariants of a partial differential operator acting on sections of a
vector bundle over a smooth manifold. We compute the first non-commutative
corrections to Einstein equations in the weak deformation limit and analyze the
spectrum of the theory. Related topics are discussed as well.Comment: 32 Pages, LaTex. Some nonessential typos in intermediate calculations
in sect. 3 and 4 are corrected. The final results are the sam
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