Pith. sign in

Elusive phase transition in the replica limit of monitored systems

3 Pith papers cite this work. Polarity classification is still indexing.

3 Pith papers citing it
abstract

We study an exactly solvable model of monitored dynamics in a system of $N$ spin-$1/2$ particles with pairwise all-to-all noisy interactions, where each spin is continuously weakly measured along a random direction. Using the replica trick to incorporate the Born-rule weighting of measurement outcomes, we obtain an exact large-$N$ description of purification and of the statistics of local observables. We find that the nature of the phase transition strongly depends on the number $n$ of replicas: non-perturbative logarithmic corrections appear in the physically relevant $n\to1$ limit and destroy the purifying phase present at finite integer $n$. As a consequence, the purification time of an initially mixed state is always exponentially long in the system size, even at arbitrarily large measurement rate.

fields

quant-ph 3

years

2026 1 2025 2

representative citing papers

Universal purification dynamics of monitored Clifford circuits

quant-ph · 2026-07-07 · accept · novelty 7.5

Purification of weakly monitored Clifford circuits on prime-dimensional qudits reduces exactly to a pure-death Markov process on the density-matrix rank, producing compact universal scaling functions for all Rényi entropies.

Measurement-Based Quantum Diffusion Models

quant-ph · 2025-08-12 · unverdicted · novelty 7.0

Measurement-based quantum diffusion models are introduced to recover pure and mixed quantum states via weak measurements, quantum score matching, and Petz recovery maps with error bounds, bridging to classical stochastic reversals.

citing papers explorer

Showing 3 of 3 citing papers.

  • Universal purification dynamics of monitored Clifford circuits quant-ph · 2026-07-07 · accept · none · ref 42 · internal anchor

    Purification of weakly monitored Clifford circuits on prime-dimensional qudits reduces exactly to a pure-death Markov process on the density-matrix rank, producing compact universal scaling functions for all Rényi entropies.

  • Measurement-induced phase transition in interacting bosons from most likely quantum trajectory quant-ph · 2025-09-29 · unverdicted · none · ref 15 · internal anchor

    A most-likely-trajectory method exactly solves Gaussian bosonic monitoring and approximates the Sine-Gordon model to show an entanglement phase transition from area-law to logarithmic scaling.

  • Measurement-Based Quantum Diffusion Models quant-ph · 2025-08-12 · unverdicted · none · ref 28 · internal anchor

    Measurement-based quantum diffusion models are introduced to recover pure and mixed quantum states via weak measurements, quantum score matching, and Petz recovery maps with error bounds, bridging to classical stochastic reversals.