arXiv subjects

Fernando Chamizo

Publications and source records attributed to Fernando Chamizo.

25 records · Page 2Linked to original sources

arXiv2017

Lattice points in elliptic paraboloids

We consider the lattice point problem corresponding to a family of elliptic paraboloids in $\mathbb{R}^d$ with $d\ge3$ and we prove the expected to be optimal exponent, improving previous results. This is especially noticeable for $d=3$ because the optimal exponent is conjectural even for the sphere. We also treat some aspects of the case $d=2$, getting for a simple parabolic region an $Ω$-result that is unknown for the classical circle and divisor problems.

math.NT↗

arXiv2017

Lattice points in bodies of revolution II

In a previous article it was shown that when a three-dimensional smooth convex body has rotational symmetry around a coordinate axis one can find better bounds for the lattice point discrepancy than what is known for more general convex bodies. To accomplish this, however, it was necessary to assume a non-vanishing condition on the third derivative of the generatrix. In this article we drop this condition, showing that the aforementioned bound holds for a wider family of revolution bodies, which includes those with analytic boundary. A novelty in our approach is that, besides the usual analytic methods, it requires studying some Diophantine properties of the Taylor coefficients of the phase on the Fourier transform side.

math.NT↗

arXiv2016

Tachyonic instabilities in 2+1 dimensional Yang-Mills theory and its connection to Number Theory

We consider the $2+1$ dimensional Yang-Mills theory with gauge group $\text{SU}(N)$ on a flat 2-torus under twisted boundary conditions. We study the possibility of phase transitions (tachyonic instabilities) when $N$ and the volume vary and certain chromomagnetic flux associated to the topology of the bundle can be adjusted. Under natural assumptions about how to match the perturbative regime and the expected confinement, we prove that the absence of tachyonic instabilities is related to some problems in number theory, namely the Diophantine approximation of irreducible fractions by other fractions of smaller denominator.

hep-th↗

arXiv2015

The Hölder exponent of some Fourier series

In this paper we study the local regularity of fractional integrals of Fourier series using several definitions of the Hölder exponent. We especially consider series coming from fractional integrals of modular forms. Our results show that in general cusp forms give rise to pure fractals (as opposed to multifractals). We include explicit examples and computer plots.

math.CA↗

arXiv2014

Lattice points in the 3-dimensional torus

We prove the exponent $4/3$ for the lattice point discrepancy of a torus in $\mathbb{R}^3$ (generated by the rotation of a circle around the $z$ axis). The exponent comes from a diagonal term and it seems a natural limit for any approach based solely on classical methods of exponential sums. The result extends to other solids in $\mathbb{R}^3$ related to the torus.

math.NT↗

arXiv2012

Multifractal behavior of polynomial Fourier series

We prove non-trivial upper and lower bounds for the "Spectrum of Singularities" of Fourier Series with polynomial frequencies. The Spectrum of Singularities of a function f gives the Hausdorff dimension of the set of points with a given Hölder exponent for f.

math.NT↗

arXiv2006

Non-Euclidean visibility problems

We consider the analog of visibility problems in hyperbolic plane (represented by Poincaré half-plane model H), replacing the standard lattice $Z\times Z$ by the orbit $z=i$ under the full modular group $z$. We prove a visibility criterion and study orchard problem and the cardinality of visible points in large circles

math.NT↗