Universal monitored dynamics in multimode bosonic systems

TL;DR

This paper introduces a method to study monitored many-body dynamics in multimode bosonic systems using circuit QED, revealing measurement-induced phase transition-like behavior and critical regimes observable with current hardware.

Contribution

It develops a framework for analyzing monitored bosonic systems with brickwork circuits, combining experimental proposals with theoretical insights into phase transitions.

Findings

Measurement-induced phase transition signatures observed

Critical-like high-measurement regime identified

Signatures detectable with near-term hardware

Abstract

We propose a route to study monitored many-body dynamics in multimode bosonic systems using circuit quantum electrodynamics. In this experimental setting, we construct several bosonic models comprising brickwork circuits built from beam-splitter gates, local parity measurements, and optional on-site Hubbard interactions, and diagnose their monitored dynamics via ancilla purification and a learnability-based probe. Under parity measurements, generic gate sets exhibit behavior that is largely consistent with a conventional measurement-induced phase transition, while a special class of beam-splitter circuits shows an apparent critical-like high-measurement regime in which purification times scale linearly with system size. We show that for realistic noise, gate, and measurement rates, these signatures are observable with near-term circuit QED hardware.