Run-and-Tumble Dynamics and Zeno--Anti-Zeno Transition in Biased Quantum Trajectories

TL;DR

This paper explores a phase transition in monitored qubits, drawing parallels with active matter, and demonstrates how measurement and feedback induce a transition akin to biological motility behaviors.

Contribution

It introduces a novel mapping between biased quantum trajectories and classical active particles, revealing measurement-induced phase transitions in quantum systems.

Findings

Identification of Zeno--Anti-Zeno transition in qubits

Mapping of quantum dynamics to classical active matter models

Insights into designing dissipative quantum systems

Abstract

We identify the transition from the oscillatory Rabi regime to the localized Zeno/Anti-Zeno regime in continuous measurement and feedback of a qubit as a quantum analogue of Motility-Induced Phase Separation (MIPS). A mapping between a biased monitored qubit and a classical ``Run-and-Tumble" active particle is studied. We demonstrate that the competition between coherent Rabi driving (analogous to active motility) and measurement-induced feedback bias (analogous to persistence) mimics the behavior of biological swimmers. This framework provides a picture of measurement-induced phase transitions using the language of active matter and offering a novel pathway for designing dissipative noisy quantum systems.