Doctoral defence: Ernest Michael Priidik Gallagher „On the internal gauge theory analogy to the Cartan Khronon theory of gravity“

29. aprillil 2026 at 14, Michael Priidik Gallagher will defend his doctoral thesis „On the internal gauge theory analogy to the Cartan Khronon theory of gravity“ („Sisemise kalibratsiooniteooria analoogiast Cartani Kroononi gravitatsiooniteooriaga“).

Supervisors:

Dr. Tomi Sebastian Koivisto, University of Tartu, National Institute of Chemical Physics and Biophysics (Estonia)

Dr. Luca Marzola, National Institute of Chemical Physics and Biophysics (Estonia)

Dr. Stefan Groote, University of Tartu

Opponent: Dr. William E. V. Barker, Central European Institute for Cosmology and Fundamental Physics, Institute of Physics of the Czech Academy of Sciences

Summary

Gravity is geometry, but actually so is all of physics – and not only geometry, but also algebra, analysis, mathematics in general, and an expression of endless creativity and exhausting work. One discipline, still theoretical but with remarkable interest, is the creation of a unified theory, which would put all interactions into a common framework. What happens if to approach this with a new perspective, based on the Cartan Khronon theory of gravity and the differential geometry of gauge theory? The doctoral work of E. M. P. Gallagher handles precisely these unification-geometric moments, how to put modern Lorentz gauge theory into the unification framework.
The Cartan Khronon theory (Zlosnik, Urban, Marzola, Koivisto) gives a new, compact, and perhaps more fundamental basis how spacetime geometry should appear. The titular Khronon field gives a direction for the flow of time, and the Lorentz symmetry breaking results additionally in dark matter dust. But how to introduce the remainder of matter and interactions? It is known that fundamental interactions, i.e. the electromagnetic, weak and strong force are described by gauge theory: a subtle mathematics of special objects, connections. The gauge theoretic nature of gravity is more nuanced, but in the Khronon theory it has a clearly similar description as the remaining interactions.
The new doctoral thesis proposes several options how to complement the rest of the interactions with the Khronon, the field of time. The wonder of all this activity is in the nature of the unified phase. How should the world appear, if gravity is indiscernible from the other interactions? Undoubtedly exotic, if the measure of distance disappears. At the same time the work does not exclude technical details on dynamics, field duality, symmetries, their breakings and conservation laws. Much work still remains: but now one of the first dissertations on the Khronon gives a strong basis that future developments can spring from.