## Abstract

We use Lightcone Conformal Truncation (LCT)—a version of Hamiltonian truncation — to study the nonperturbative, real-time dynamics of ϕ

^{4}-theory in 2+1 dimensions. This theory has UV divergences that need to be regulated. We review how, in a Hamiltonian framework with a total energy cutoff, renormalization is necessarily state-dependent, and UV sensitivity cannot be canceled with standard local operator counter-terms. To overcome this problem, we present a prescription for constructing the appropriate state-dependent counterterms for (2+1)d ϕ^{4}-theory in lightcone quantization. We then use LCT with this counterterm prescription to study ϕ^{4}-theory, focusing on the ℤ_{2}symmetry-preserving phase. Specifically, we compute the spectrum as a function of the coupling and demonstrate the closing of the mass gap at a (scheme-dependent) critical coupling. We also compute Lorentz-invariant two-point functions, both at generic strong coupling and near the critical point, where we demonstrate IR universality and the vanishing of the trace of the stress tensor.Original language | English |
---|---|

Article number | 190 |

Journal | Journal of High Energy Physics |

Volume | 2021 |

DOIs | |

Publication status | Published - 20 May 2021 |

## Keywords

- hep-th
- cond-mat.stat-mech
- cond-mat.str-el
- hep-lat

## Fingerprint

Dive into the research topics of 'Nonperturbative dynamics of (2+1)d*ϕ*

^{4}-theory from Hamiltonian truncation'. Together they form a unique fingerprint.