Entanglement and absorbing state transitions in $(d+1)$-dimensional stabilizer circuits

TL;DR

This paper investigates how feedback operations influence entanglement and absorbing state phase transitions in higher-dimensional monitored quantum circuits, revealing distinct universality classes and the conditions under which transitions coincide or remain separate.

Contribution

It extends previous one-dimensional results to higher dimensions, analyzing the effects of short-range and global feedback operations on phase transitions in stabilizer circuits.

Findings

Absorbing state transition belongs to d-dimensional directed percolation universality class.

Entanglement transition depends on feedback operation type and can be separated from the absorbing state transition.

Global control operations can cause the two critical points to coincide, with universality class potentially differing.

Abstract

We study the influence of feedback operations on the dynamics of $(d+1)$-dimensional monitored random quantum circuit. Competition between unitary dynamics and measurements leads to an entanglement phase transition, while the feedback steers the dynamics towards an absorbing state, yielding an absorbing state phase transition. Building on previous results in one spatial dimension [Phys. Rev. Lett. 130, 120402 (2023)], we discuss the interplay between the two types of transitions for $d \ge 2$ in the presence of (i) short-range feedback operations or (ii) additional global control operations. In both cases, the absorbing state transition belongs to the $d$-dimensional directed percolation universality class. In contrast, the entanglement transition depends on the feedback operation type and reveals the dynamics' inequivalent features. The entanglement and absorbing state phase transition remain separated for short-range feedback operations. When global control operations are applied, we find the two critical points coinciding; nevertheless, the universality class may still differ, depending on the choice of the control operation.