Results 31 to 40 of about 979 (82)
Vacuum Polarization Energy for General Backgrounds in One Space Dimension [PDF]
, 2017 For field theories in one time and one space dimensions we propose an efficient method to compute the vacuum polarization energy of static field configurations that do not allow a decomposition into symmetric and anti--symmetric channels. The method also
Weigel, H.
core +3 more sources
A Consistent Heteroskedasticity‐Robust LM‐Type Specification Test for Semiparametric Models
Journal of Applied Econometrics, Volume 41, Issue 3, Page 240-252, April/May 2026.ABSTRACT This article develops a heteroskedasticity‐robust Lagrange Multiplier‐type specification test for semiparametric regression models. The test is able to detect a wide class of deviations from the null hypothesis. The test statistic is based on the estimates from the restricted semiparametric model, can be computed in a regression‐based way, and
Ivan Korolev
wiley +1 more source
A Levinson theorem for scattering from a Bose-Einstein condensate
, 2003 A relation between the number of bound collective excitations of an atomic Bose-Einstein condensate and the phase shift of elastically scattered atoms is derived.
Brand, J., Haering, I., Rost, J. -M.
core +1 more source
Potential scattering and the continuity of phase-shifts [PDF]
, 2012 Let $S(k)$ be the scattering matrix for a Schr\"odinger operator (Laplacian plus potential) on $\RR^n$ with compactly supported smooth potential. It is well known that $S(k)$ is unitary and that the spectrum of $S(k)$ accumulates on the unit circle only ...
Gell-Redman, Jesse, Hassell, Andrew
core +2 more sources
The legacy of the Cartwright–Littlewood collaboration
Journal of the London Mathematical Society, Volume 113, Issue 1, January 2026.Abstract Mary L. Cartwright and John E. Littlewood published a short “preliminary survey” in 1945 describing results of their investigation of the forced van der Pol equation ÿ−k(1−y2)ẏ+y=bλkcos(λt+a)$$\begin{equation*} \ddot{y}-k(1-y^2)\dot{y}+y = b \lambda k \cos (\lambda t+a) \end{equation*}$$in which b,λ,k,a$b,\lambda,k,a$ are parameters with k$k$
John Guckenheimer
wiley +1 more source
Uniqueness of polynomial canonical representations
, 2007 Let P(z) and Q(y) be polynomials of the same degree k>=1 in the complex variables z and y, respectively. In this extended abstract we study the non-linear functional equation P(z)=Q(y(z)), where y(z) is restricted to be analytic in a neighborhood of z=0.
Lladser, Manuel
core +4 more sources
A Hilton–Milner theorem for exterior algebras
Transactions of the London Mathematical Society, Volume 12, Issue 1, December 2025.Abstract Recent work of Scott and Wilmer and of Woodroofe extends the Erdős–Ko–Rado theorem from set systems to subspaces of k$k$‐forms in an exterior algebra. We prove an extension of the Hilton–Milner theorem to the exterior algebra setting, answering in a strong way a question asked by these authors.
Denys Bulavka +2 more
wiley +1 more source
Neutron-proton scattering and singular potentials
, 2018 We consider a Bargmann-type rational parametrization of the nucleon scattering phase shifts. Applying Marchenko's method of quantum inverse scattering we show that the scattering data suggest a singular repulsive core of the potential of the form $2/r^2$
Balog, Janos +2 more
core +1 more source
Estimation and Inference for Higher‐Order Stochastic Volatility Models With Leverage
Journal of Time Series Analysis, Volume 46, Issue 6, Page 1064-1084, November 2025.ABSTRACT Statistical inference—estimation and testing—for stochastic volatility models is challenging and computationally expensive. This problem is compounded when leverage effects are allowed. We propose efficient, simple estimators for higher‐order stochastic volatility models with leverage [SVL(p)$$ (p) $$], based on a small number of moment ...
Md. Nazmul Ahsan +2 more
wiley +1 more source
Pion dissociation and Levinson's theorem in hot PNJL quark matter
, 2013 Pion dissociation by the Mott effect in quark plasma is described within the generalized Beth-Uhlenbeck approach on the basis of the PNJL model which allows for a unified description of bound, resonant and scattering states.
Blaschke, D. +3 more
core +1 more source