David D. Reid 
Lecturer (part-time)
Executive Officer & Senior Lecturer (Retired)
Department of Physics, University of Chicago
5720 South Ellis Avenue, room 205B
Chicago, Illinois 60637
Phone: 773-702-7013
E-mail (research): ddr.research@gmail.com
E-mail (UChicago): dreid@uchicago.edu
http://home.uchicago.edu/~dreid/

Research Interests
My work is mostly, but not exclusively, computational and touches mainly on the areas highlighted below. In addition to those mentioned below I have a developing interest in quantitative biophysics, particularly, but not exclusively, theoretical neuroscience.

Causal Sets

AIP Conf Proc 991, p. 5, Fig. 1

The causal set hypothesis supposes that the deep structure of spacetime is that of a locally finite partially ordered set. The set is locally finite because this model postulates that spacetime is discrete rather than continuous. The partial ordering - that some elements of the set have a specific relative order while others do not - provides the model with a built-in notion of causality.

The ultimate goal is to use this construct as the foundation for a theory of quantum gravity in which spacetime is discrete. However, my own interest is in the interface between causal sets and classical gravity (general relativity), especially aspects of the Order + Number ⇒ Geometry correspondence that is one of its foundational concepts.

There are many reasons to investigate the prospect that spacetime might be discrete. These reasons come from the study of black holes in classical gravity, certain aspects of quantum field theory, and many other considerations. For a discussion of some of these reasons see, Causal Sets: Discrete Gravity, by Rafael Sorkin. Many other introductory and review articles on causal sets are available. For one of the more recent ones see, The causal set approach to quantum gravity, by Sumati Surya. One of mine can be found here.

Research projects currently in my plans include the following.

  • manifold dimension of a causal set
  • embedding alorithms
  • a general study of causal sets in flat spacetime
  • curvature measures

Electron- and Positron-Gas Scattering

Phys Rev A 70, 062714, Fig. 2

The determination of quantum mechanical scattering cross sections continues to be a useful probe into the interactions of atoms and molecules. Cross sections are also important inputs for understanding transport phenomena in gases and other aspects of gaseous dynamics.

In this work, conducted with J. M. Wadehra at Wayne State University, we seek to understand major (even global) trends in the interaction of electrons and positrons in atomic and molecular gases. Our current work focuses on electron and positron scattering from atoms in the alkali-earth group.

Our calculations are performed using complex model interaction potentials. The model potential for polarization effects, which also (partially) takes into account correlation effects, was developed by us and introduced in this paper. Similarly, the model potential used for inelastic scattering of positrons was worked out by us and introduced here together with a key correction.

Current and future work includes the following.

  • Electron and positron scattering from alkali-earth atoms.
  • A new model to approximate e± scattering from molecules.
  • Critical minima in differential cross sections.
  • The Ramsauer-Townsend effect

Physics Pedagogy

EJP 20, p. 129, Fig. 2b

I also work in physics pedagogy, which I distinguish from physics education research. By physics pedagogy I mean finding ways to explain certain (known) phenomena that are either more elucidating, more complete, more accurate, or just different (in some useful way) than the expositions typically found in textbooks.

Current project ideas are related to the following.

  • Doppler Effect
  • Hubble Law
  • Electrocardiogram

A Few Selected Papers

  • Zily Burstein, David D. Reid, Peter J. Thomas, and Jack D. Cowan, "Pattern forming mechanisms of color vision," Network Neuroscience, vol. 7, iss. 2, 679 (2023).

  • Finian Ashmead and David D. Reid, "Estimating the manifold dimension of causal sets." In: Bambi, C., Modesto, L., Shapiro, I. (eds) Handbook of Quantum Gravity. Springer, Singapore (2024).

  • David D. Reid and J. M. Wadehra, "Electron and positron scattering by atomic beryllium," European Physical Journal D, vol. 74, 112 (2020).

  • He Liu and David D. Reid, "A new approach for embedding causal sets into Minkowski space," Classical and Quantum Gravity, vol. 35, 124002 (2018).

  • David D. Reid and J. M. Wadehra, "Scattering of low-energy electrons and positrons by atomic beryllium: Ramsauer-Townsend effect," Journal of Physics B: Atomic, Molecular and Optical Physics, vol. 47, 225211 (2014).

  • David D. Reid, "Embeddings of Causal Sets," in Proceedings of the 2008 Joint Annual Conference of the National Society of Black Physicists and the National Society of Hispanic Physicists, AIP Conference Proceedings, 1140, pp. 60−68 (2009).

  • Raluca Ilie, Gregory B. Thompson, and David D. Reid, "A numerical study of the correspondence between paths in a causal set and geodesics in the continuum," Classical and Quantum Gravity, vol. 23, pp. 3275−3285 (2006).

  • David D. Reid, William B. Klann, and J. M. Wadehra, "Scattering of low- to intermediate-energy positrons from molecular hydrogen," Physical Review A, vol. 70, 062714 (2004).

  • David D. Reid, "Manifold Dimension of a Causal Set: Tests in conformally flat spacetimes," Physical Review D, 67, 024034 (2003).

  • Natthi L. Sharma and David D. Reid,"Rolling as a frictional equilibration of translation and rotation," European Journal of Physics, vol. 20, pp. 129−136 (1999).

  • David D. Reid and J. M. Wadehra, "Scattering of intermediate- to high-energy positrons by alkali-metal atoms," Physical Review A, vol. 57, pp. 2583−2589 (1998).
University of Chicago                                                                                                                                                    Udated : Dec 2023