IAS Physics Group Meeting

This group meeting will be presented in-person in the Bloomberg Lecture Hall at the IAS and on Zoom. The Zoom link will be provided in the email announcement.

For contact-tracing purposes all off-campus attendees must register for this seminar: 
REGISTRATION FORM

All in-person attendees must be fully vaccinated, including a booster dose, and masks are optional in all indoor spaces. Additionally, all off-campus attendees are required to upload proof of vaccination that includes a booster dose via the IAS CrowdPass App . 

Abstract: We revisit the lattice formulation of the Schwinger model using the Kogut-Susskind Hamiltonian approach with staggered fermions. This model, introduced by Banks et al., contains the mass term $m_{\rm lat} \sum_{n} (-1)^{n} \chi^\dagger_n \chi_n$, and setting it to zero is often assumed to provide the lattice regularization of the massless Schwinger model. We instead argue that the relation between the lattice and continuum mass parameters should be taken as $m_{\rm lat}=m- \frac{1}{8} e^2 a$. The model with $m=0$ is shown to possess a discrete chiral symmetry that is generated by the unit lattice translation accompanied by the shift of the $\theta$-angle by $\pi$. While the mass shift vanishes as the lattice spacing $a$ approaches zero, we find that including this shift greatly improves the rate of convergence to the continuum limit. We demonstrate the faster convergence using both numerical diagonalizations of finite lattice systems, as well as extrapolations of the lattice strong coupling expansions.

The talk will be based mostly on the recent paper in collaboration with Ross Dempsey, Silviu Pufu and Bernardo Zan:

[2206.05308] Discrete Chiral Symmetry and Mass Shift in Lattice Hamiltonian Approach to Schwinger Model (arxiv.org)