arXiv subjects

Costas Efthimiou

Publications and source records attributed to Costas Efthimiou.

10 recordsLinked to original sources

arXiv2020

Electrostatics and Riemann Surfaces

Using techniques from geometry and complex analysis in their simplest form, we present a derivation of electric fields on surfaces with non-trivial topology. A byproduct of this analysis is an intuitive visualization of elliptic functions when their argument is complex-valued. The underlying connections between these techniques and the theory of Riemann surfaces are also explained. Our goal is to provide students and instructors a quick reference article for an extraordinary topic that is not included in the standard books.

physics.gen-ph↗

arXiv2018

Investigation of Skyscraper's Feat (original version with an addendum)

Skyscraper is a Hollywood action film directed and written by Rawson M. Thurber scheduled to be released on July 13, 2018. We present an exhaustive analysis of the feat shown in the recently released teaser poster and trailer of the film. Although the feat appears to be unrealistic at first glance, after close investigation using back-of-the-envelope calculations, it is seen to be within human capabilities. This article is the original version of an abridged article published in Physics Education. It was written very soon after the poster and clip were released by Universal Pictures.

physics.pop-ph↗

arXiv2016

Household Income Distribution in the USA

In this article we present an alternative model for the distribution of household incomes in the United States. We provide arguments from two differing perspectives which both yield the proposed income distribution curve, and then fit this curve to empirical data on household income distribution obtained from the United States Census Bureau.

q-fin.GN↗

arXiv2013

String Theory has no Isotropic Solution for the Modified Einstein's Equations without the Dilaton

We investigate the modification to Einstein's vacuum field equations which is imposed by string theory when the dilaton field is ignored. Including the cosmological constant in all calculations, we prove that such a theory of gravity admits no static isotropic solution. We then show that any isotropic solution of the equations in question must necessarily be static, therefore proving that no isotropic solution exists for this stringy modification to gravity.

hep-th↗

arXiv2011

Implementing Elements of The Physics Suite at a Large Metropolitan Research University

A key question in physics education is the effectiveness of the teaching methods. A curriculum that has been investigated at the University of Central Florida (UCF) over a period of two years is the use of particular elements of The Physics Suite. Select sections of the introductory physics classes at UCF have made use of Interactive Lecture Demonstrations as part of the lecture component of the class. The lab component of the class has implemented the RealTime Physics curriculum, again in select sections. The remaining sections have continued with the teaching methods traditionally used. Using pre- and post-semester concept inventory tests, a student survey, student interviews, and a standard for successful completion of the course, the data indicates improved student learning.

physics.ed-ph↗

arXiv1998

Finding Exact Values For Infinite Sums

This paper offers a solution method that allows one to find exact values for a large class of convergent series of rational terms. Sums of this form arise often in problems dealing with Quantum Field Theory.

math-ph↗

arXiv1997

Minimal Models of CFT on Z_N-Surfaces

The conformal field theory on a Z_N-surface is studied by mapping it on the branched sphere. Using a coulomb gas formalism we construct the minimal models of the theory.

hep-th↗

arXiv1997

Shape Invariance in the Calogero and Calogero-Sutherland Models

We show that the Calogero and Calogero-Sutherland models possess an N-body generalization of shape invariance. We obtain the operator representation that gives rise to this result, and discuss the implications of this result, including the possibility of solving these models using algebraic methods based on this shape invariance. Our representation gives us a natural way to construct supersymmetric generalizations of these models, which are interesting both in their own right and for the insights they offer in connection with the exact solubility of these models.

quant-ph↗

arXiv1994

Form Factors of 2-D Integrable Models Using Radial Quantization

We review some ideas from a recent construction which introduced the notion of vertex operators and form factors as vacuum expectation values of related vertex operators in the space of fields. The vertex operators are constructed explicitly in radial quantization. These ideas are explained at the free-fermion point of the sine-Gordon theory.

hep-th↗

arXiv1993

Particle-Field Duality and Form Factors from Vertex Operators

Using a duality between the space of particles and the space of fields, we show how one can compute form factors directly in the space of fields. This introduces the notion of vertex operators, and form factors are vacuum expectation values of such vertex operators in the space of fields. The vertex operators can be constructed explicitly in radial quantization. Furthermore, these vertex operators can be exactly bosonized in momentum space. We develop these ideas by studying the free-fermion point of the sine-Gordon theory, and use this scheme to compute some form-factors of some non-free fields in the sine-Gordon theory. This work further clarifies earlier work of one of the authors, and extends it to include the periodic sector.

hep-th↗