Multipartite entanglement structure of monitored quantum circuits
Pith reviewed 2026-05-23 06:21 UTC · model grok-4.3
The pith
Unstructured monitored random circuits lack divergent multipartite entanglement even at criticality.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
Unstructured monitored random circuits fail to exhibit divergent multipartite entanglement even at criticality, highlighting their departure from standard quantum critical behavior. However, genuinely multipartite entangled phases can be realized through two-site measurements, provided a protection mechanism is in place.
What carries the argument
Quantum Fisher information as a lens for multipartite entanglement structure in monitored phases.
If this is right
- Multipartite entanglement serves as a diagnostic that distinguishes monitored phases from standard critical points.
- Two-site measurements open a route to genuinely multipartite entangled phases when combined with protection.
- The same perspective extends to the study of interacting monitored circuits and noisy quantum dynamics.
- Unstructured random monitoring alone is insufficient to produce the entanglement scaling expected at criticality.
Where Pith is reading between the lines
- Measurement-induced transitions in fully random circuits may belong to a distinct universality class that does not produce the usual entanglement divergences.
- Protection mechanisms could be realized by adding symmetries or feedback rules that suppress local disentangling effects.
- The approach invites comparison with other open-system settings where multipartite probes have been applied to phase transitions.
Load-bearing premise
A protection mechanism can be implemented to enable genuinely multipartite entangled phases via two-site measurements.
What would settle it
A direct computation of the quantum Fisher information in an unstructured monitored random circuit at the critical measurement rate that shows clear divergence would falsify the reported absence of divergent multipartite entanglement.
Figures
read the original abstract
Monitored quantum circuits have attracted significant interest as an example of synthetic quantum matter, intrinsically defined by their quantum information content. Here, we propose a multipartite entanglement perspective on monitored phases through the lens of quantum Fisher information. Our findings reveal that unstructured monitored random circuits fail to exhibit divergent multipartite entanglement even at criticality, highlighting their departure from standard quantum critical behavior. However, we demonstrate that genuinely multipartite entangled phases can be realized through two-site measurements, provided a protection mechanism is in place. This work positions multipartite entanglement as a valuable perspective for the study of interacting monitored circuits and broader frameworks of noisy quantum dynamics.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The manuscript proposes a multipartite entanglement perspective on monitored quantum phases via quantum Fisher information. It claims that unstructured monitored random circuits do not exhibit divergent multipartite entanglement even at criticality (departing from standard quantum critical behavior) but that genuinely multipartite entangled phases can be realized through two-site measurements when a protection mechanism is present.
Significance. If the claims are substantiated with explicit constructions and scaling data, the work would supply a new diagnostic for entanglement structure in monitored circuits and a route to engineering multipartite phases under noise, potentially broadening the classification of measurement-induced phases beyond bipartite measures.
major comments (1)
- [Abstract] Abstract: the central positive claim—that genuinely multipartite entangled phases are realized via two-site measurements 'provided a protection mechanism is in place'—is load-bearing yet supplies no definition, circuit modification, measurement protocol, or Fisher-information calculation, rendering the claim unevaluable from the given text.
Simulated Author's Rebuttal
We thank the referee for their comments. The primary concern raised is that the abstract's central claim lacks sufficient detail to be evaluable. We agree that the abstract is concise and will revise it to better summarize the key elements while pointing to the main text for definitions and calculations.
read point-by-point responses
-
Referee: [Abstract] Abstract: the central positive claim—that genuinely multipartite entangled phases are realized via two-site measurements 'provided a protection mechanism is in place'—is load-bearing yet supplies no definition, circuit modification, measurement protocol, or Fisher-information calculation, rendering the claim unevaluable from the given text.
Authors: We acknowledge that the abstract, standing alone, does not define the protection mechanism, specify the circuit modification, detail the measurement protocol, or include the Fisher-information calculation. The full manuscript develops these elements in the main text with explicit constructions. To make the claim more evaluable from the abstract itself, we will revise it to include a brief definition of the protection mechanism and reference the relevant sections containing the protocols and scaling data. revision: yes
Circularity Check
No circularity: abstract presents claims without any derivation chain or self-referential structure
full rationale
The provided document consists solely of the abstract, which states findings from a proposed perspective on monitored circuits using quantum Fisher information. No equations, derivations, fitted parameters, or citations appear. Claims about unstructured circuits and multipartite phases via two-site measurements are framed as empirical or analytical results rather than definitions or tautologies. No self-citation load-bearing steps, ansatzes, or renamings are present. The derivation chain cannot be walked because none is supplied; the text is self-contained as a high-level summary of external analysis.
Axiom & Free-Parameter Ledger
axioms (1)
- domain assumption Quantum Fisher information serves as a valid lens for multipartite entanglement structure in monitored quantum circuits
Forward citations
Cited by 1 Pith paper
-
Rise and fall of nonstabilizerness via random measurements
Analytical and numerical study of stabilizer nullity and Rényi entropies in monitored Clifford circuits shows quantized decay for computational measurements and size-dependent relaxation to a non-trivial steady state ...
Reference graph
Works this paper leans on
- [1]
-
[2]
M. P. Fisher, V. Khemani, A. Nahum, and S. Vijay, Annu. Rev. Condens. Matter Phys. 14, 335 (2023)
work page 2023
-
[3]
M. J. Gullans and D. A. Huse, Phys. Rev. X 10, 041020 (2020)
work page 2020
-
[4]
M. J. Gullans, S. Krastanov, D. A. Huse, L. Jiang, and S. T. Flammia, Phys. Rev. X 11, 031066 (2021)
work page 2021
- [5]
-
[6]
U. Agrawal, J. Lopez-Piqueres, R. Vasseur, S. Gopalakr- ishnan, and A. C. Potter, Phys. Rev. X 14, 041012 (2024)
work page 2024
- [7]
- [8]
- [9]
- [10]
-
[11]
R. Horodecki, P. Horodecki, M. Horodecki, and K. Horodecki, Rev. Mod. Phys. 81, 865 (2009)
work page 2009
-
[12]
P. Calabrese and J. Cardy, J. Phys. A: Math. Theor. 42, 504005 (2009)
work page 2009
- [13]
-
[14]
C. Noel, P. Niroula, D. Zhu, A. Risinger, L. Egan, D. Biswas, M. Cetina, A. V. Gorshkov, M. J. Gullans, D. A. Huse, and C. Monroe, Nat. Phys. 18, 760 (2022)
work page 2022
-
[15]
J. M. Koh, S.-N. Sun, M. Motta, and A. J. Minnich, Nat. Phys. 19, 1314 (2023)
work page 2023
-
[16]
Google AI Quantum and collaborators, Nature 622, 481 (2023)
work page 2023
-
[17]
A. C. Potter and R. Vasseur, Entanglement dynamics in hybrid quantum circuits, inEntanglement in Spin Chains (Springer International Publishing, 2022) p. 211
work page 2022
-
[18]
O. Lunt, J. Richter, and A. Pal, Quantum simulation us- ing noisy unitary circuits and measurements, inEntangle- ment in Spin Chains (Springer International Publishing,
-
[19]
Y. Li, X. Chen, and M. P. Fisher, Phys. Rev. B 98, 205136 (2018)
work page 2018
-
[20]
Y. Li, X. Chen, and M. P. Fisher, Phys. Rev. B 100, 134306 (2019)
work page 2019
- [21]
-
[22]
C.-M. Jian, Y.-Z. You, R. Vasseur, and A. W. W. Ludwig, 6 Phys. Rev. B 101, 104302 (2020)
work page 2020
-
[23]
Y. Bao, S. Choi, and E. Altman, Phys. Rev. B 101, 104301 (2020)
work page 2020
- [24]
- [25]
-
[26]
S. P. Kelly, U. Poschinger, F. Schmidt-Kaler, M. P. A. Fisher, and J. Marino, SciPost Phys. 15, 250 (2023)
work page 2023
-
[27]
L. Colmenarez, Z.-M. Huang, S. Diehl, and M. M¨ uller, Phys. Rev. Res. 6, L042014 (2024)
work page 2024
-
[28]
F. Eckstein, B. Han, S. Trebst, and G.-Y. Zhu, PRX Quantum 5, 040313 (2024)
work page 2024
-
[29]
F. Venn, J. Behrends, and B. B´ eri, Phys. Rev. Lett.131, 060603 (2023)
work page 2023
-
[30]
P. Niroula, C. D. White, Q. Wang, S. Johri, D. Zhu, C. Monroe, C. Noel, and M. J. Gullans, Nat. Phys. 20, 1786–1792 (2024)
work page 2024
- [31]
-
[32]
G. E. Fux, E. Tirrito, M. Dalmonte, and R. Fazio, Phys. Rev. Res. 6, L042030 (2024)
work page 2024
-
[33]
A. Paviglianiti, G. Lami, M. Collura, and A. Silva, (2024), arXiv:2405.06054 [quant-ph]
-
[34]
A. Gu, S. F. E. Oliviero, and L. Leone, (2024), arXiv:2403.19610 [quant-ph]
work page internal anchor Pith review Pith/arXiv arXiv 2024
- [35]
-
[36]
M. J. Gullans and D. A. Huse, Phys. Rev. Lett. 125, 070606 (2020)
work page 2020
-
[37]
Y. Li, Y. Zou, P. Glorioso, E. Altman, and M. P. A. Fisher, Phys. Rev. Lett. 130, 220404 (2023)
work page 2023
-
[38]
H. Kamakari, J. Sun, Y. Li, J. J. Thio, T. P. Gujarati, M. P. A. Fisher, M. Motta, and A. J. Minnich, (2024), arXiv:2403.00938 [quant-ph]
-
[39]
S. L. Braunstein and C. M. Caves, Phys. Rev. Lett. 72, 3439 (1994)
work page 1994
-
[40]
M. G. Paris, Int. J. Quantum Inf. 7, 125 (2009)
work page 2009
- [41]
-
[42]
V. Giovannetti, S. Lloyd, and L. Maccone, Nat. Photonics 5, 222 (2011)
work page 2011
- [43]
- [44]
- [45]
-
[46]
Quantum theory of phase estimation
L. Pezze’ and A. Smerzi, (2014), arXiv:1411.5164 [quant- ph]
work page internal anchor Pith review Pith/arXiv arXiv 2014
-
[47]
L. Pezz` e, A. Smerzi, M. K. Oberthaler, R. Schmied, and P. Treutlein, Rev. Mod. Phys. 90, 035005 (2018)
work page 2018
-
[48]
J. Liu, H. Yuan, X.-M. Lu, and X. Wang, J. Phys. A: Math. Theor. 53, 023001 (2019)
work page 2019
-
[49]
M. Yu, Y. Liu, P. Yang, M. Gong, Q. Cao, S. Zhang, H. Liu, M. Heyl, T. Ozawa, N. Goldman, and J. Cai, npj Quantum Info. 8, 56 (2022)
work page 2022
- [50]
-
[51]
G. Passarelli, X. Turkeshi, A. Russomanno, P. Lucig- nano, M. Schir` o, and R. Fazio, Phys. Rev. Lett. 132, 163401 (2024)
work page 2024
-
[52]
P. M. Poggi and M. H. Mu˜ noz-Arias, Quantum 8, 1229 (2024)
work page 2024
-
[53]
D. M. Greenberger, M. A. Horne, and A. Zeilinger, (2007), arXiv:0712.0921 [quant-ph]
work page internal anchor Pith review Pith/arXiv arXiv 2007
-
[54]
Throughout this work, the Pauli matrices acting on site i are denoted as ˆσα i with α = x, y, z
-
[55]
C. N. Yang, Rev. Mod. Phys. 34, 694 (1962)
work page 1962
- [56]
-
[57]
L. Pezz` e, M. Gabbrielli, L. Lepori, and A. Smerzi, Phys. Rev. Lett. 119, 250401 (2017)
work page 2017
-
[58]
S. Pappalardi, A. Russomanno, A. Silva, and R. Fazio, J. Stat. Mech.: Theory Exp. 2017 (5), 053104
work page 2017
- [59]
-
[60]
P. Laurell, A. Scheie, C. J. Mukherjee, M. M. Koza, M. Enderle, Z. Tylczynski, S. Okamoto, R. Coldea, D. A. Tennant, and G. Alvarez, Phys. Rev. Lett. 127, 037201 (2021)
work page 2021
- [61]
- [62]
- [63]
-
[64]
M. M. Rams, P. Sierant, O. Dutta, P. Horodecki, and J. Zakrzewski, Phys. Rev. X 8, 021022 (2018)
work page 2018
-
[65]
Y. Chu, S. Zhang, B. Yu, and J. Cai, Phys. Rev. Lett. 126, 010502 (2021)
work page 2021
- [66]
- [67]
-
[68]
P. Sierant, M. Schir` o, M. Lewenstein, and X. Turkeshi, Phys. Rev. B 106, 214316 (2022)
work page 2022
-
[69]
Y. Li, X. Chen, A. W. W. Ludwig, and M. P. A. Fisher, Phys. Rev. B 104, 104305 (2021)
work page 2021
-
[70]
J.-Y. Desaules, F. Pietracaprina, Z. Papi´ c, J. Goold, and S. Pappalardi, Phys. Rev. Lett. 129, 020601 (2022)
work page 2022
-
[71]
Crucially, the computation remains non-trivial even in the limit p → 0, corresponding to purely unitary dynam- ics |ψt⟩ = U |ψ0⟩ for some unitary operator U. Specifi- cally, the local rotations depend on the evolution oper- ator U (nj ) j (U), and averaging over circuit realizations is non-linear, cf. also Ref. [50]. A similar reasoning holds also in the ...
-
[72]
X. Chen, Y. Li, M. P. A. Fisher, and A. Lucas, Phys. Rev. Res. 2, 033017 (2020)
work page 2020
- [73]
- [74]
-
[75]
Rep. Prog. Phys. 43, 833 (1980)
work page 1980
-
[76]
S. Sang, Y. Li, T. Zhou, X. Chen, T. H. Hsieh, and M. P. Fisher, PRX Quantum 2, 030313 (2021)
work page 2021
- [77]
- [78]
- [79]
- [80]
discussion (0)
Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.