Theory of Measurement-Altered Criticality

• URL: http://arxiv.org/abs/2608.05289v1
• Date: Wed, 05 Aug 2026 18:00:03 GMT
• Title: Theory of Measurement-Altered Criticality
• Abstract summary: Local measurements can alter long-range correlations in gapless quantum matter.<n>We propose a theory of weakly-monitored Tomonaga-Luttinger liquids, a broad class of quantum critical states in one dimension.
• Score: 0.10923877073891443
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: Local measurements can alter long-range correlations in gapless quantum matter. We propose a theory of weakly-monitored Tomonaga-Luttinger liquids, a broad class of quantum critical states in one dimension. In order to address the intrinsic randomness of the measurement record, we develop a replica instanton calculation to study Born-averaged observables. We find that when measurements are relevant, average correlators of density and phase fluctuations decay at long distances as universal power laws with logarithmic corrections, a feature we argue is peculiar to measurement-induced randomness. We characterize the full multifractal spectrum of moments of correlations functions, revealing broad, strongly non-gaussian fluctuations across the ensemble of post-measurement states. We support these analytic results with matrix-product-state calculations, and provide a general picture of measurement-altered criticality for ground states described by 1+1d conformal field theories. Our results establish that physical measurements alter critical quantum states in a manner that lies beyond both forced measurements and conventional critical scaling.

Related papers

• Measurement-Induced Entanglement in Conformal Field Theory [0.0]
  We study measurement-induced entanglement in Tomonaga-Luttinger liquids.<n>We show that the MIE is entirely universal, conformally invariant, and depends on the operator content of the CFT.<n>We show that the MIE for physical quantum measurements is fundamentally different from the entanglement induced by forcing measurement outcomes.
  arXiv  Detail & Related papers  (2025-08-04T18:01:22Z)
• Enhanced Entanglement in the Measurement-Altered Quantum Ising Chain [43.80709028066351]
  Local quantum measurements do not simply disentangle degrees of freedom, but may actually strengthen the entanglement in the system.<n>This paper explores how a finite density of local measurement modifies a given state's entanglement structure.
  arXiv  Detail & Related papers  (2023-10-04T09:51:00Z)
• Quantifying measurement-induced quantum-to-classical crossover using an open-system entanglement measure [49.1574468325115]
  We study the entanglement of a single particle under continuous measurements. We find that the entanglement at intermediate time scales shows the same qualitative behavior as a function of the measurement strength.
  arXiv  Detail & Related papers  (2023-04-06T09:45:11Z)
• Evolution of many-body systems under ancilla quantum measurements [58.720142291102135]
  We study the concept of implementing quantum measurements by coupling a many-body lattice system to an ancillary degree of freedom. We find evidence of a disentangling-entangling measurement-induced transition as was previously observed in more abstract models.
  arXiv  Detail & Related papers  (2023-03-13T13:06:40Z)
• Nonlocality and entanglement in measured critical quantum Ising chains [0.0]
  Local degrees of freedom in critical states exhibit long-range entanglement. We study the effects of measurements, performed with a finite density in space, on the ground state of the one-dimensional transverse-field Ising model at criticality.
  arXiv  Detail & Related papers  (2023-01-19T19:03:37Z)
• Full counting statistics as probe of measurement-induced transitions in the quantum Ising chain [62.997667081978825]
  We show that local projective measurements induce a modification of the out-of-equilibrium probability distribution function of the local magnetization. In particular we describe how the probability distribution of the former shows different behaviour in the area-law and volume-law regimes.
  arXiv  Detail & Related papers  (2022-12-19T12:34:37Z)
• Observation of partial and infinite-temperature thermalization induced by repeated measurements on a quantum hardware [62.997667081978825]
  We observe partial and infinite-temperature thermalization on a quantum superconducting processor. We show that the convergence does not tend to a completely mixed (infinite-temperature) state, but to a block-diagonal state in the observable basis.
  arXiv  Detail & Related papers  (2022-11-14T15:18:11Z)
• Measurements conspire nonlocally to restructure critical quantum states [0.0]
  We study how local measurements perfomed on critical quantum ground states affect long-distance correlations. We show that arbitrarily weak local measurements, performed over extended regions of space, can conspire to drive transitions in long-distance correlations.
  arXiv  Detail & Related papers  (2022-07-19T18:00:06Z)
• Continuous Gaussian Measurements of the Free Boson CFT: A model for Exactly Solvable and Detectable Measurement-Induced Dynamics [0.0]
  We introduce a scenario of measurement-induced many body evolution, which possesses an exact analytical solution: bosonic measurements. We consider an elementary model for quantum criticality, the free boson conformal field theory, and investigate in which way criticality is modified under measurements. For each scenario, we discuss the impact of imperfect measurements, which reduce the purity of the wavefunction and are equivalent to Markovian decoherence.
  arXiv  Detail & Related papers  (2021-08-09T18:00:04Z)
• Generalized quantum measurements with matrix product states: Entanglement phase transition and clusterization [58.720142291102135]
  We propose a method for studying the time evolution of many-body quantum lattice systems under continuous and site-resolved measurement. We observe a peculiar phenomenon of measurement-induced particle clusterization that takes place only for frequent moderately strong measurements, but not for strong infrequent measurements.
  arXiv  Detail & Related papers  (2021-04-21T10:36:57Z)
• Entanglement detection in quantum many-body systems using entropic uncertainty relations [0.0]
  We study experimentally accessible lower bounds on entanglement measures based on entropic uncertainty relations. We derive an improved entanglement bound for bipartite systems, which requires measuring joint probability distributions in only two different measurement settings per subsystem.
  arXiv  Detail & Related papers  (2021-01-21T20:50:11Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.