Messengers from imaginary time: instantons and topological non-perturbative physics — from quantum mechanics to QCD and experimental searches
by
Abstract:
The universe we observe is real, yet the path integral that governs it runs over complex field configurations — invisible to perturbation theory, the default tool of quantum field theory. What it misses is a whole zoo of topological, non-perturbative objects: solitons and monopoles, domain walls and cosmic strings, sphalerons, baryon junctions, and instantons. These are not abstractions: confinement is non-perturbative, and the masses and spins of the hadrons around us have no perturbative explanation. Taking instantons as the guiding example, the talk follows them from a particle tunneling through a double well — messengers from imaginary time (t → -iτ) — to the heart of QCD: the θ-vacuum, strong CP and its axion, and chiral symmetry breaking, meeting topology and resurgence. A second example is the baryon junction — a gluonic Y-topology that may carry baryon number rather than the valence quarks. The second half turns to experiment: can such objects be detected? We review instanton searches at HERA and the LHC, the junction search at RHIC, and the prospects both open at the Electron-Ion Collider — no confirmed signal yet, but the next decade may change that.
The seminar will be held in the Dvořák hall, FZU, Pod Vodárenskou věží 1, Prague.
Location: https://goo.gl/maps/wEf7PsiLimSXMZhE9
The seminar will be also available via ZOOM video conference system:
Meeting ID: 674 9629 6646
Passcode: 575511
or join meeting via direct ZOOM link
Jiří Hejbal and Roman Lysák