Critical Coupling for Two-dimensional $\phi^4$ Theory in Discretized Light-Cone Quantization

TL;DR

This paper determines the critical coupling in 2D $\,phi^4$ theory using Discretized Light-Cone Quantization, finding results consistent with some methods but differing from others by 17%.

Contribution

It introduces a method to compute the critical coupling in 2D $\,phi^4$ theory with DLCQ, comparing results across different quantization approaches.

Findings

Critical coupling consistent with conformal truncation results.

17% difference from light-front quantization with polynomial basis.

Neglecting zero mode still yields reliable critical coupling estimate.

Abstract

We solve for the critical coupling in the symmetric phase of two-dimensional $\phi^4$ field theory using Discretized Light-Cone Quantization. We adopt periodic boundary conditions, neglect the zero mode, and obtain a critical coupling consistent with the critical coupling reported using conformal truncation in light-front quantization. We find a 17% dfference from the critical coupling reported with light-front quantization in a symmetric polynomial basis.