Gen Z and Digital Distractions in the Classroom: Student Classroom Use of Digital Devices for Non-Class Related Purposes

A 2019 survey of college students examined classroom-learning distractions caused by their use of digital devices for non-class purposes. The purpose of the survey, part of an on-going study, was to learn more about students’ behaviors and perceptions regarding their classroom uses of digital devices for non-class purposes. The survey included 986 respondents in 37 U.S. states and 47 respondents in Alberta, Canada. A significant feature of the study was its measurement of frequency and duration of students’ classroom digital distractions as well as respondents’ motivations for engaging in the distracting behavior. Respondents averaged 19.4% of class time using a digital device for non-class purposes. The average respondent used a digital device 9.06 times during a typical school day in the 2019 survey for non-class purposes. On a weighted average, survey respondents indicated they would turn-off all non-class digital distractions if their instructor gave them 7.8% extra credit on their final class grade

From Form Factors to Correlation Functions: The Ising Model

Using exact expressions for the Ising form factors, we give a new very simple proof that the spin-spin and disorder-disorder correlation functions are governed by the Painlev\'e III non linear differential equation. We also show that the generating function of the correlation functions of the descendents of the spin and disorder operators is a $N$-soliton, $N\to\infty$, $\tau$-function of the sinh-Gordon hierarchy. We discuss a relation of our approach to isomonodromy deformation problems, as well as further possible generalizations.Comment: SPhT-92-062; LPTHE-92-2

Basic hardware interconnection mechanisms for building multiple microcomputer systems

This report presents the current results of a research project which has been concerned with methods for designing and implementing multiple microcomputer systems. The design method is based upon identifying hardware interconnection primitives which may be used to construct the interconnection subsystem which characterizes a given multicomputer architecture. An actual experimental system has been constructed which will permit building nine of ten systems in the Anderson and Jensen architecture taxonomy. (Author)Supported in part by the Department of Electrical Engineering and Computer Science, University of Connecticut, Storrs, Connecticut and in part by the Department of Computer Science, Naval Postgraduate School, Monterey, Californiahttp://archive.org/details/basichardwareint00careNAApproved for public release; distribution is unlimited

Universal, finite temperature, crossover functions of the quantum transition in the Ising chain in a transverse field

We consider finite temperature properties of the Ising chain in a transverse field in the vicinity of its zero temperature, second order quantum phase transition. New universal crossover functions for static and dynamic correlators of the ``spin'' operator are obtained. The static results follow from an early lattice computation of McCoy, and a method of analytic continuation in the space of coupling constants. The dynamic results are in the ``renormalized classical'' region and follow from a proposed mapping of the quantum dynamics to the Glauber dynamics of a classical Ising chain.Comment: substantial re-arrangement of presentation, but no additional result

Finite temperature correlations in the one-dimensional quantum Ising model

We extend the form-factors approach to the quantum Ising model at finite temperature. The two point function of the energy is obtained in closed form, while the two point function of the spin is written as a Fredholm determinant. Using the approach of \Korbook, we obtain, starting directly from the continuum formulation, a set of six differential equations satisfied by this two point function. Four of these equations involve only spacetime derivatives, of which three are equivalent to the equations obtained earlier in \mccoy,\perk. In addition, we obtain two new equations involving a temperature derivative. Some of these results are generalized to the Ising model on the half line with a magnetic field at the origin.Comment: 37 pages, uses harvmac, minor changes in the last two paragraphs, updating some conjecture

Exact expectation values of local fields in quantum sine-Gordon model

We propose an explicit expression for vacuum expectation values of the exponential fields in the sine-Gordon model. Our expression agrees both with semi-classical results in the sine-Gordon theory and with perturbative calculations in the Massive Thirring model. We use this expression to make new predictions about the large-distance asymptotic form of the two-point correlation function in the XXZ spin chain.Comment: 18 pages, harvmac.tex, 2 figure

A cryogenic liquid-mirror telescope on the moon to study the early universe

We have studied the feasibility and scientific potential of zenith observing liquid mirror telescopes having 20 to 100 m diameters located on the moon. They would carry out deep infrared surveys to study the distant universe and follow up discoveries made with the 6 m James Webb Space Telescope (JWST), with more detailed images and spectroscopic studies. They could detect objects 100 times fainter than JWST, observing the first, high-red shift stars in the early universe and their assembly into galaxies. We explored the scientific opportunities, key technologies and optimum location of such telescopes. We have demonstrated critical technologies. For example, the primary mirror would necessitate a high-reflectivity liquid that does not evaporate in the lunar vacuum and remains liquid at less than 100K: We have made a crucial demonstration by successfully coating an ionic liquid that has negligible vapor pressure. We also successfully experimented with a liquid mirror spinning on a superconducting bearing, as will be needed for the cryogenic, vacuum environment of the telescope. We have investigated issues related to lunar locations, concluding that locations within a few km of a pole are ideal for deep sky cover and long integration times. We have located ridges and crater rims within 0.5 degrees of the North Pole that are illuminated for at least some sun angles during lunar winter, providing power and temperature control. We also have identified potential problems, like lunar dust. Issues raised by our preliminary study demand additional in-depth analyses. These issues must be fully examined as part of a scientific debate we hope to start with the present article.Comment: 35 pages, 11 figures. To appear in Astrophysical Journal June 20 200

Difference Equations in Spin Chains with a Boundary

Correlation functions and form factors in vertex models or spin chains are known to satisfy certain difference equations called the quantum Knizhnik-Zamolodchikov equations. We find similar difference equations for the case of semi-infinite spin chain systems with integrable boundary conditions. We derive these equations using the properties of the vertex operators and the boundary vacuum state, or alternatively through corner transfer matrix arguments for the 8-vertex model with a boundary. The spontaneous boundary magnetization is found by solving such difference equations. The boundary $S$-matrix is also proposed and compared, in the sine-Gordon limit, with Ghoshal--Zamolodchikov's result. The axioms satisfied by the form factors in the boundary theory are formulated.Comment: 28 pages, LaTeX with amssymbols.sty, 7 uuencoded postscript figure

gl(N|N) Super-Current Algebras for Disordered Dirac Fermions in Two Dimensions

We consider the non-hermitian 2D Dirac Hamiltonian with (A): real random mass, imaginary scalar potential and imaginary gauge field potentials, and (B) arbitrary complex random potentials of all three kinds. In both cases this Hamiltonian gives rise to a delocalization transition at zero energy with particle-hole symmetry in every realization of disorder. Case (A) is in addition time-reversal invariant, and can also be interpreted as the random-field XY Statistical Mechanics model in two dimensions. The supersymmetric approach to disorder averaging results in current-current perturbations of $gl(N|N)$ super-current algebras. Special properties of the $gl(N|N)$ algebra allow the exact computation of the beta-functions, and of the correlation functions of all currents. One of them is the Edwards-Anderson order parameter. The theory is `nearly conformal' and possesses a scale-invariant subsector which is not a current algebra. For N=1, in addition, we obtain an exact solution of all correlation functions. We also study the delocalization transition of case (B), with broken time reversal symmetry, in the Gade-Wegner (Random-Flux) universality class, using a GL(N|N;C)/U(N|N) sigma model, as well as its PSL(N|N) variant, and a corresponding generalized random XY model. For N=1 the sigma model is shown to be identical to the current-current perturbation. For the delocalization transitions (case (A) and (B)) a density of states, diverging at zero energy, is found.Comment: LaTeX, 40 page

Mass Generation in Perturbed Massless Integrable Models

We extend form-factor perturbation theory to non--integrable deformations of massless integrable models, in order to address the problem of mass generation in such systems. With respect to the standard renormalisation group analysis this approach is more suitable for studying the particle content of the perturbed theory. Analogously to the massive case, interesting information can be obtained already at first order, such as the identification of the operators which create a mass gap and those which induce the confinement of the massless particles in the perturbed theory