Spring 2026 Colloquium Schedule

Colloquia are Wednesdays at 4:00 p.m. in the JILA Auditorium.

Coffee, tea and cookies will be available in G1B31 (across from G1B20) from 3:30 - 3:50 p.m.

January 14 — Joint Physics-APS Colloquium, "String Theory Reborn"

  • Presenter: Andrew Hamilton, CU Boulder
  • Host: Mike Litos
  • Abstract: String theory offers a viable theory of quantum gravity, with spin 2 gravitons encoded in closed strings.  But the failure to find evidence for supersymmetry at the LHC has left string theory in an uncertain state.  A solution to the problem is in plain sight: revert to classic nonsupersymmetric, bosonic string theory, reenvisaged as a theory of all the forces, not just the strong force.  The classic theory correctly reproduces the Brauer-Weyl (1935) algebraic relation between fermions and bosons seen in the standard model, whereas supersymmetry does not. 
    Sages rejected the classic theory on the grounds that (1) it does not admit fermions, and (2) its ground state is tachyonic.  But rejection (1) assumes that fermions are strings, whereas the fermions of bosonic string theory are the endpoints of strings, and are not themselves strings; in modern parlance, the fermions are excitations of the D-brane boundary of strings.  As to rejection (2), the properties of the tachyon are precisely those of a Higgs field: it is a multiplet of the unbroken symmetry; the "vacuum" state where the Higgs field vanishes identically is tachyonically unstable; and it has spin zero.  The gauge group of bosonic string theory is tightly constrained.  I show that a 26-dimensional bosonic string theory that fits the standard model emerges without contrivance.  Unburdened by supersymmetry, bosonic string theory has the potential to bring string theory back into the realm of testable physics accessible to present-day observation and experiment.

January 21

  • Presenter: Libai Huang, Purdue University
  • Host: Markus Raschke
  • Abstract:

January 28

  • Presenter: Noel Clark, CU Boulder
  • Host: Leo Radzihovsky
  • Abstract:

February 4

  • Presenter: Andrew Gettelman, PNNL
  • Host: Ivy Tan
  • Abstract:

February 11

  • Presenter: Eric Bittner, University of Houston
  • Host: Sean Shaheen
  • Abstract:

February 18

  • Presenter: Terry Wallace, Lawrence Livermore National Laboratory
  • Host: Markus Raschke
  • Abstract:

February 25

  • Presenter: Adam Koberinski, Rotman Institute of Philosophy, Western University
  • Host: Heather Demarest
  • Abstract:

March 4

  • Presenter: Hamish Gordon, Carnegie Mellon University
  • Host: Ivy Tan
  • Abstract:

March 11

  • Presenter: Ben Lev, Stanford University
  • Host: Ana Maria Rey
  • Abstract:

No Colloquium March 18 — Spring Break

March 25

  • Presenter: Mehran Kardar, Massachusetts Institute of Technology
  • Host: Leo Radzihovsky
  • Abstract:

April 1

  • Presenter: Scott Pratt, Michigan State University
  • Host: Jamie Nagle
  • Abstract:

April 8

  • Presenter: Rachel Henderson, Michigan State University
  • Host: Bethany Wilcox
  • Abstract:

April 15

  • Presenter: Phil Nelson, University of Pennsylvania
  • Host: Leo Radzihovsky
  • Abstract:

April 22

  • Presenter: Long Ju, Massachusetts Institute of Technology
  • Host: Victor Gurarie
  • Abstract:

For more information about colloquia this semester, contact: Mike Litos