# Quantum dissipation in a scalar field theory with gapped momentum states

## TL;DR

This paper introduces a non-perturbative approach to modeling quantum dissipation in scalar field theories, revealing how dissipation induces a momentum gap and modifies particle properties, with implications for understanding dissipative quantum systems.

## Contribution

It presents a novel non-perturbative method to incorporate dissipation into scalar field theories, demonstrating the emergence of gapped momentum states and their effects on particle dynamics.

## Key findings

- Dissipation creates a momentum gap in the scalar field.
- Dissipation leads to particle mass dressing and energy reduction.
- The mechanism is analogous to transverse modes in liquids.

## Abstract

Understanding quantum dissipation is important from both theoretical perspective and applications. Here, we show how to describe dissipation in a scalar field theory. We treat dissipation non-perturbatively, represent it by a bilinear term in the Lagrangian and quantize the theory. We find that dissipation promotes a gap in momentum space and reduces the particle energy. As a result, particle mass becomes dressed by dissipation due to self-interaction. The underlying mechanism is similar to that governing the propagation of transverse collective modes in liquids. We discuss the interplay between the dissipative and mass terms, the associated different regimes of field dynamics and the emergence of ultraviolet and infrared cutoffs due to dissipation.