Aspects of spontaneous symmetry breaking in LCT

Note: Recording:
Password: gaf?MpP9
Speaker: Kyriakos Grammatikos, Boston University

When: November 23, 2020 (Mon), 03:00PM to 04:00PM (add to my calendar)
Hosted by: Eric Boyers

This event is part of the Graduate Student Council Events.

Part of the student seminar series. A recording will be posted on the event page.

Abstract: QFT still remains an elusive subject about 80 years after its conception. While remaining the only consistent framework for the relativistic treatment of quantum particles, it boasts a vast phenomenological variety and it still poses conceptual and computational challenges, one being the detection of phase transitions in strongly interacting QFTs. The majority of existing tools rely on putting QFTs on a lattice, a powerful approach that requires however treating the theory in finite volume and extrapolating to obtain dynamical quantities. In this talk, I present a tool that aims to fill this gap. Lightcone Conformal Truncation (LCT) is a computational scheme that marries together the power of conformal field theories and lightcone quantization in a framework capable of extracting variational approximations to infinite volume correlation functions and more importantly, an approximation to the spectrum of a field theory, which may reveal important information about the low-lying bound states of the theory. We use our tool to investigate a boson in a quartic potential with a cubic deformation, a model known to exhibit a transition, which at weak coupling is a product of spontaneous symmetry breaking. We present results on the spectrum, correlation functions and the map of the phase transition and discuss possible emergent descriptions for the line of criticality.