REVIEW 3 major objections 5 minor 4 cited by
A Universal Protocol for Quantum-Enhanced Sensing via Information Scrambling
T0 review · 3 major / 5 minor · reviewed 2026-08-12 · deepseek-v4-flash
Pith's one-line read Butterfly metrology uses forward and reverse evolution under a generic many-body Hamiltonian to reach a sensitivity within a factor of two of the Heisenberg limit, with the sensitivity exactly a sum of local out-of-time-order correlators.
desk verdict Butterfly metrology is a genuinely new and clever protocol with an exact OTOC-sensitivity relation; the headline universality claim is undercut by its own conservation-law analysis, but the core idea survives and deserves refereeing. read the letter →
The pith
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
The reading
What carries the argument
The carrying object is the butterfly state and its OTOC identity. A local $\pi/2$-pulse $(1+iV)/\sqrt{2}$ splits the evolution into an identity branch that returns to $|0\rangle$ and a perturbation branch that becomes $V(t)|0\rangle$; a final forward evolution refocuses the accumulated phase into the local observable $V$. The identity $\eta^{-1}_{\phi=0} = \frac{1}{2}\sum_i\left(1-\langle0|\sigma_i^z V(t)\sigma_i^z V(t)|0\rangle\right)$ equates sensitivity with the summed decay of local OTOCs, so operator growth—ballistic for short-range interactions, exponential for all-to-all interactions—sets the rise of sensitivity from the standard quantum limit to $2/N$ by the scrambling time.
What would settle it
For a delocalized but integrable spin chain with conserved total $S_z$, starting from a fully polarized state, evaluate the small-signal sensitivity at times well beyond the scrambling time: the universal claim predicts $\eta\approx 2/N$, whereas the conservation-law formula predicts $\eta^{-1}=N(1-m)/2$; finding $\eta^{-1}$ of order one rather than of order $N$ would falsify the claim that any non-localized Hamiltonian reaches Heisenberg scaling.
Extended reading notes
Core claim
The central claim is that the state $|\psi_B\rangle = (|0\rangle + i V(t)|0\rangle)/\sqrt{2}$, produced by evolving a local perturbation forward and then backward under the same many-body unitary, is a metrological resource for essentially any non-localized Hamiltonian. Under fully scrambling dynamics the scrambled branch $V(t)|0\rangle$ has zero mean polarization, so the two branches are separated by a macroscopic polarization difference; the sensitivity reads $\eta^{-1}_{\phi=0} = N/2 - \langle 0 | V(t) S_z V(t) | 0\rangle = \frac{1}{2}\sum_i \left(1 - \langle 0 | \sigma_i^z V(t) \sigma_i^z V(t) |0\rangle\right)$, an exact sum of local out-of-time-order correlators. As $V(t)$ grows to act on all $N$ spins each OTOC decays, giving $\eta \approx 2/N$. The same construction with only global rotations and global readout reaches $\eta \approx \sqrt{2e}/N \approx 2.3/N$, and the paper provides pulse sequences and numerics for dense ensembles of NV centers.
Load-bearing premise
The Heisenberg enhancement rests on the assumption that the scrambled branch $V(t)|0\rangle$ has essentially zero mean polarization at late times; this holds for fully scrambling non-integrable dynamics but fails for integrable delocalized systems and for Hamiltonians with conserved charges that keep both branches polarized, where the paper's own formula gives $\eta^{-1}=N(1-m)/2$ and the enhancement shrinks or disappears.
Editorial extensions
If this is right
- Any non-localized interacting system becomes a Heisenberg-limited sensor after its scrambling time, so state preparation no longer requires special Hamiltonians.
- The exact OTOC identity makes the protocol a direct probe of scrambling: the inverse sensitivity counts the spins reached by $V(t)$, so time-resolved sensitivity maps the operator light cone.
- The global-control variant reaches $\eta\approx 2.3/N$ using only collective rotations and readout, extending Heisenberg scaling to platforms without single-site addressing.
- Since beating the standard quantum limit certifies multipartite entanglement, the protocol doubles as a generic entanglement witness for quench dynamics.
- In the proposed NV-center implementations, numerical simulations show saturation at the predicted $\eta\approx 2/N$, indicating the enhancement is achievable with currently accessible dipolar spin systems.
Reading between the lines
- One extension the authors leave implicit: the same protocol can serve as an operational thermometer for scrambling time, because the saturation of $\eta^{-1}$ coincides with the operator light cone covering the system; measuring sensitivity versus time yields the butterfly velocity and the effective dimension.
- The conservation-law caveat sharpens the boundary of the universality claim: integrable delocalized systems should not show the enhancement even though they are not localized, so the working definition of 'generic' excludes more than just many-body localization.
- The OTOC identity suggests a practical benchmark for quantum processors: run forward/reverse evolution around a single-qubit perturbation, extract $\eta^{-1}$, and read off whether the device scrambles as expected.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper introduces 'butterfly metrology,' a sensing protocol in which a forward/backward many-body evolution sequence interleaved with a local rotation prepares a coherent superposition of a polarized state and a 'scrambled' state. The signal is then imprinted by a collective rotation about Sz, and a final forward evolution followed by a local measurement yields a sensitivity that the authors show, in Eqs. (2)-(4), is exactly expressible through a sum of local out-of-time-order correlators. For late-time fully scrambling dynamics the claimed sensitivity is η≈2/N, within a factor of two of the Heisenberg limit. A global-control variant, detailed experimental blueprints (NV-P1 hybrids, NV ensembles, Rydberg arrays, cavities, superconducting qubits, trapped ions), and a noise analysis are also presented.
Significance. If the stated universality held, this would be a significant advance: it would turn generic interacting many-body dynamics into a resource for Heisenberg-limited sensing and would substantially broaden the set of experimental platforms for quantum-enhanced metrology. The OTOC identity in Eq. (4) is elegant and exact, the derivation of Eq. (3) from the protocol is transparent, and the numerical studies for concrete spin-defect platforms are a strength, as is the explicit treatment of readout, initialization, and incoherent errors. The central caveat is that the 'any non-localized Hamiltonian' claim is not supported by the paper's own conservation-law analysis; the headline statement needs a substantive qualification, not just local rewriting.
major comments (3)
- [Eq. (3) and final paragraph of 'Sensitivity from operator growth'] The conservation-law discussion in the final paragraph is load-bearing and is not consistent with Eq. (3). For any Hamiltonian with [H,Sz]=0 and for the main-text initial state |0>=|0>^⊗N, the scrambled branch V(t)|0> has total Sz=N/2−1 for all t, because V=σx flips exactly one spin and U preserves Sz. Eq. (3) then gives η^{-1}=N/2−⟨0|V(t)Sz V(t)|0⟩=1, independent of N. In the same paragraph's notation m=1, so the claimed prefactor N(1−m)/2 vanishes rather than yielding a Heisenberg-scaling sensitivity. This is not a slight deviation: the sensitivity is below the standard quantum limit, and it occurs in delocalized, strongly interacting, fully scrambling models such as the XXZ chain. The manuscript's abstract and introductory claims therefore need to be restricted to Hamiltonians and initial states for which the Gibbs polarization density m is strictly less than 1.
- [General strategy and Eq. (5)] The assertion that the protocol works for 'essentially any Hamiltonian, so long as it is not localized' is unsupported for delocalized integrable systems. Ballistic operator growth, which is what Eq. (5) uses, is not sufficient for the local OTOCs in Eq. (4) to decay to zero; in integrable models such as the XX chain, local OTOCs saturate at nonzero values, so the scrambled branch does not have zero mean polarization. The paper does not provide a proof or even a discussion that non-integrability is required, and the numerical examples are all nonintegrable or effectively random circuits. At minimum, the universality claim should be replaced by a precise scrambling assumption and a discussion of which classes of delocalized dynamics satisfy it.
- [Main text protocol vs. Supplemental Material Sec. III, first paragraph and Table I] There is a mismatch between the main-text recipe and the experimental prescriptions that actually avoid the conservation-law obstruction. The main text prepares the z-polarized state |0> and states the protocol works for any non-localized Hamiltonian; the Supplemental Material, by contrast, states that the native interactions of essentially all proposed platforms conserve total Sz polarization and therefore chooses initial states quantized along X, or averages over random X-basis product states. The main-text headline claim should either incorporate this qualification explicitly or prove that the z-polarized initialization still works when the Gibbs polarization density m in Eq. (5) is computed correctly. As written, a reader following the main-text protocol with a Sz-conserving Hamiltonian obtains no Heisenberg enhancement.
minor comments (5)
- [Main text, paragraph following Fig. 2(b)] There is a typo: 'Heisenerg-scaling sensitivity' should be 'Heisenberg-scaling sensitivity'.
- [Eq. (5)] Eq. (5) refers to 'Fig. 2(d)', but Fig. 2 has only panels (a), (b), and (c).
- [Abstract and 'General strategy'] The phrase 'using the dynamics of any interacting many-body Hamiltonian' is too strong even for the late-time scrambling regime, as discussed in the major comments; the abstract should state the scrambling and initial-state conditions under which η≈2/N is derived.
- [Supplemental Material Sec. III, first paragraph] The prescription of initializing in the X basis while choosing a butterfly operator V=σx is confusing: a random product state in the X basis is an eigenstate of σx, so the local rotation (1+iV)/√2 does not create the desired superposition. The authors should clarify the exact basis convention, or specify the transverse operator used in each platform.
- [Supplemental Material Sec. IV] The stochastic model's conversion factor between discrete time steps and continuous evolution time is extracted by matching to small-size exact dynamics; the large-N predictions shown in the insets of Fig. 4 therefore inherit a fitted calibration and should be described as extrapolations rather than parameter-free predictions.
Circularity Check
Derivation is self-contained: the sensitivity–OTOC identity is an exact algebraic reformulation, and the Heisenberg-scaling claim rests on an explicit fully-scrambling assumption, not on fitted inputs or load-bearing self-citations.
full rationale
The paper's central derivation chain is not circular. Equation (3), eta^{-1} = N/2 - <0|V(t)S_zV(t)|0>, follows directly from the small-signal expansion of the readout expectation value in Eq. (2), and Eq. (4) rewrites this as a sum of local OTOCs using only sigma^z_i|0>=|0>. This is a mathematical identity, not an equivalence assumed by construction. The Heisenberg-scaling sensitivity eta~2/N is obtained under the explicitly stated condition that U is fully scrambling, i.e. that the scrambled branch V(t)|0> has zero mean polarization; this is a physical assumption about late-time dynamics, and the paper supports it with Haar-random averaging and exact numerics, rather than fitting a parameter and relabeling it a prediction. The conservation-law discussion in the final main-text paragraph and the supplemental choice of transverse butterfly operators and X-basis initial states acknowledge an important limitation of the 'any Hamiltonian' claim, but a limitation is not a circular step. Self-citations, including Ref. [80] for Loschmidt-echo noise suppression, are used for secondary robustness estimates and standard OTOC properties; none is the load-bearing justification of the central sensitivity result. No fitted parameter is renamed as a prediction, and no uniqueness theorem or prior ansatz is imported to forbid alternatives. Accordingly, no circular step can be exhibited from the paper's own equations.
Assumptions & free parameters
free parameters (1)
- Stochastic model time-step conversion factor =
Not stated explicitly; matched to exact dynamics at early times in SM Fig. S5
assumptions (4)
- domain assumption Fully scrambling dynamics make the scrambled branch V(t)|0> have zero mean polarization, or at least polarization density m<1 in the relevant Gibbs ensemble.
- domain assumption The engineered pulse sequences realize high-fidelity time-reversed evolution U† of the full many-body Hamiltonian in the proposed platforms.
- domain assumption The stochastic operator growth model with Clifford circuits and Haar-random gates accurately captures the exact long-time sensitivity dynamics of the spin-defect systems.
- standard math Clifford unitaries form a 3-design, so Haar-random gate averages can be replaced by Clifford averages for the sensitivity.
Cite this review
Pith. "Pith review of A Universal Protocol for Quantum-Enhanced Sensing via Information Scrambling." pith.science (2026). https://pith.science/paper/GLCPPRB5
@misc{pith2026241112794,
author = {Pith},
title = {Pith review of: A Universal Protocol for Quantum-Enhanced Sensing via Information Scrambling},
year = {2026},
howpublished = {\url{https://pith.science/paper/GLCPPRB5}},
note = {Machine review of arXiv:2411.12794}
}
read the original abstract
We introduce a novel protocol, which enables Heisenberg-limited quantum-enhanced sensing using the dynamics of any interacting many-body Hamiltonian. Our approach - dubbed butterfly metrology - utilizes a single application of forward and reverse time evolution to produce a coherent superposition of a "scrambled" and "unscrambled" quantum state. In this way, we create metrologically-useful long-range entanglement from generic local quantum interactions. The sensitivity of butterfly metrology is given by a sum of local out-of-time-order correlators (OTOCs) - the prototypical diagnostic of quantum information scrambling. Our approach broadens the landscape of platforms capable of performing quantum-enhanced metrology; as an example, we provide detailed blueprints and numerical studies demonstrating a route to scalable quantum-enhanced sensing in ensembles of solid-state spin defects.
Figures
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Reference graph
Works this paper leans on
-
[1]
Giovannetti, S
V. Giovannetti, S. Lloyd, and L. Maccone, Quantum metrology, Physical review letters 96, 010401 (2006). 6
2006
-
[2]
Pezze, A
L. Pezze, A. Smerzi, M. K. Oberthaler, R. Schmied, and P. Treutlein, Quantum metrology with nonclassical states of atomic ensembles, Reviews of Modern Physics 90, 035005 (2018)
2018
-
[3]
Giovannetti, S
V. Giovannetti, S. Lloyd, and L. Maccone, Advances in quantum metrology, Nature photonics 5, 222 (2011)
2011
-
[4]
C. L. Degen, F. Reinhard, and P. Cappellaro, Quantum sensing, Reviews of modern physics 89, 035002 (2017)
2017
-
[5]
J. M. Robinson, M. Miklos, Y. M. Tso, C. J. Kennedy, T. Bothwell, D. Kedar, J. K. Thompson, and J. Ye, Direct comparison of two spin-squeezed optical clock ensembles at the 10- 17 level, Nature Physics 20, 208 (2024)
2024
-
[6]
A. L. Shaw, R. Finkelstein, R. B.-S. Tsai, P. Scholl, T. H. Yoon, J. Choi, and M. Endres, Multi-ensemble metrology by programming local rotations with atom movements, Nature Physics , 1 (2024)
2024
-
[7]
Komar, E
P. Komar, E. M. Kessler, M. Bishof, L. Jiang, A. S. Sørensen, J. Ye, and M. D. Lukin, A quantum network of clocks, Nature Physics 10, 582 (2014)
2014
-
[8]
Schnabel, N
R. Schnabel, N. Mavalvala, D. E. McClelland, and P. K. Lam, Quantum metrology for gravitational wave astron- omy, Nature communications 1, 121 (2010)
2010
Show all 140 references
-
[9]
J. Aasi, J. Abadie, B. Abbott, R. Abbott, T. Abbott, M. Abernathy, C. Adams, T. Adams, P. Addesso, R. Ad- hikari, et al. , Enhanced sensitivity of the ligo gravita- tional wave detector by using squeezed states of light, Nature Photonics 7, 613 (2013)
2013
-
[10]
M. e. Tse, H. Yu, N. Kijbunchoo, A. Fernandez-Galiana, P. Dupej, L. Barsotti, C. Blair, D. Brown, S. Dwyer, A. Effler, et al., Quantum-enhanced advanced ligo detec- tors in the era of gravitational-wave astronomy, Physical Review Letters 123, 231107 (2019)
2019
-
[11]
Kucsko, P
G. Kucsko, P. C. Maurer, N. Y. Yao, M. Kubo, H. J. Noh, P. K. Lo, H. Park, and M. D. Lukin, Nanometre- scale thermometry in a living cell, Nature 500, 54 (2013)
2013
-
[12]
Y. Wu, F. Jelezko, M. B. Plenio, and T. Weil, Diamond quantum devices in biology, Angewandte Chemie Inter- national Edition 55, 6586 (2016)
2016
-
[13]
Bakhshandeh, Quantum sensing goes bio, Nature Re- views Materials 7, 254 (2022)
S. Bakhshandeh, Quantum sensing goes bio, Nature Re- views Materials 7, 254 (2022)
2022
-
[14]
Aslam, H
N. Aslam, H. Zhou, E. K. Urbach, M. J. Turner, R. L. Walsworth, M. D. Lukin, and H. Park, Quantum sensors for biomedical applications, Nature Reviews Physics 5, 157 (2023)
2023
-
[15]
Bradley, J
R. Bradley, J. Clarke, D. Kinion, L. J. Rosenberg, K. van Bibber, S. Matsuki, M. M¨ uck, and P. Sikivie, Microwave cavity searches for dark-matter axions, Reviews of Mod- ern Physics 75, 777 (2003)
2003
-
[16]
Zheng, M
H. Zheng, M. Silveri, R. Brierley, S. Girvin, and K. Lehnert, Accelerating dark-matter axion searches with quantum measurement technology, arXiv preprint arXiv:1607.02529 (2016)
2016 arXiv
-
[17]
Aybas, J
D. Aybas, J. Adam, E. Blumenthal, A. V. Gramolin, D. Johnson, A. Kleyheeg, S. Afach, J. W. Blanchard, G. P. Centers, A. Garcon, et al. , Search for axionlike dark matter using solid-state nuclear magnetic resonance, Physical Review Letters 126, 141802 (2021)
2021
-
[18]
Lehnert, Quantum enhanced metrology in the search for fundamental physical phenomena, SciPost Physics Lecture Notes , 040 (2022)
K. Lehnert, Quantum enhanced metrology in the search for fundamental physical phenomena, SciPost Physics Lecture Notes , 040 (2022)
2022
-
[19]
T´ oth and I
G. T´ oth and I. Apellaniz, Quantum metrology from a quantum information science perspective, Journal of Physics A: Mathematical and Theoretical 47, 424006 (2014)
2014
-
[20]
X.-M. Lu, S. Yu, and C. Oh, Robust quantum metro- logical schemes based on protection of quantum fisher information, Nature communications 6, 7282 (2015)
2015
-
[21]
Fr¨ owis, P
F. Fr¨ owis, P. Sekatski, and W. D¨ ur, Detecting large quan- tum fisher information with finite measurement precision, Physical review letters 116, 090801 (2016)
2016
-
[22]
J. Liu, H. Yuan, X.-M. Lu, and X. Wang, Quantum fisher information matrix and multiparameter estima- tion, Journal of Physics A: Mathematical and Theoretical 53, 023001 (2020)
2020
-
[23]
Agarwal and L
G. Agarwal and L. Davidovich, Quantifying quantum- amplified metrology via fisher information, Physical Re- view Research 4, L012014 (2022)
2022
-
[24]
J. G. Bohnet, K. C. Cox, M. A. Norcia, J. M. Weiner, Z. Chen, and J. K. Thompson, Reduced spin measure- ment back-action for a phase sensitivity ten times be- yond the standard quantum limit, Nature Photonics 8, 731 (2014)
2014
-
[25]
Zhang, R
H. Zhang, R. McConnell, S. ´Cuk, Q. Lin, M. H. Schleier- Smith, I. D. Leroux, and V. Vuleti´ c, Collective state mea- surement of mesoscopic ensembles with single-atom res- olution, Physical review letters 109, 133603 (2012)
2012
-
[26]
Goldstein, P
G. Goldstein, P. Cappellaro, J. R. Maze, J. Hodges, L. Jiang, A. S. Sørensen, and M. Lukin, Environment- assisted precision measurement, Physical review letters 106, 140502 (2011)
2011
-
[27]
Davis, G
E. Davis, G. Bentsen, and M. Schleier-Smith, Approach- ing the heisenberg limit without single-particle detection, Physical review letters 116, 053601 (2016)
2016
-
[28]
Macr` ı, A
T. Macr` ı, A. Smerzi, and L. Pezz` e, Loschmidt echo for quantum metrology, Physical Review A 94, 010102 (2016)
2016
-
[29]
Colombo, E
S. Colombo, E. Pedrozo-Pe˜ nafiel, A. F. Adiyatullin, Z. Li, E. Mendez, C. Shu, and V. Vuleti´ c, Time-reversal-based quantum metrology with many-body entangled states, Nature Physics 18, 925 (2022)
2022
-
[30]
G. J. Mooney, G. A. White, C. D. Hill, and L. C. Hollenberg, Generation and verification of 27-qubit greenberger-horne-zeilinger states in a superconducting quantum computer, Journal of Physics Communications 5, 095004 (2021)
2021
-
[31]
Kitagawa and M
M. Kitagawa and M. Ueda, Squeezed spin states, Physical Review A 47, 5138 (1993)
1993
-
[32]
I. D. Leroux, M. H. Schleier-Smith, and V. Vuleti´ c, Im- plementation of cavity squeezing of a collective atomic spin, Physical Review Letters 104, 073602 (2010)
2010
-
[33]
R. J. Lewis-Swan, M. A. Norcia, J. R. Cline, J. K. Thompson, and A. M. Rey, Robust spin squeezing via photon-mediated interactions on an optical clock transi- tion, Physical review letters 121, 070403 (2018)
2018
-
[34]
Zou, L.-N
Y.-Q. Zou, L.-N. Wu, Q. Liu, X.-Y. Luo, S.-F. Guo, J.-H. Cao, M. K. Tey, and L. You, Beating the classical pre- cision limit with spin-1 dicke states of more than 10,000 atoms, Proceedings of the National Academy of Sciences 115, 6381 (2018)
2018
-
[35]
Luo, Y.-Q
X.-Y. Luo, Y.-Q. Zou, L.-N. Wu, Q. Liu, M.-F. Han, M. K. Tey, and L. You, Deterministic entanglement gen- eration from driving through quantum phase transitions, Science 355, 620 (2017)
2017
-
[36]
L¨ ucke, M
B. L¨ ucke, M. Scherer, J. Kruse, L. Pezz´ e, F. Deuret- zbacher, P. Hyllus, O. Topic, J. Peise, W. Ertmer, J. Arlt, et al., Twin matter waves for interferometry beyond the classical limit, Science 334, 773 (2011). 7
2011
-
[38]
Hyllus, O
P. Hyllus, O. G¨ uhne, and A. Smerzi, Not all pure entan- gled states are useful for sub-shot-noise interferometry, Physical Review A 82, 012337 (2010)
2010
-
[39]
D. A. Abanin, E. Altman, I. Bloch, and M. Serbyn, Col- loquium: Many-body localization, thermalization, and entanglement, Reviews of Modern Physics 91, 021001 (2019)
2019
-
[40]
Such OTOCs display substan- tially different physics than standard probes of scram- bling
We remark that prior work introducing a connection be- tween quantum-enhanced sensing and information scram- bling relied on a non-standard OTOC involving a highly non-local operator [84]. Such OTOCs display substan- tially different physics than standard probes of scram- blin...
-
[41]
Kitaev, A simple model of quantum holography (2015)
A. Kitaev, A simple model of quantum holography (2015)
2015
-
[42]
S. H. Shenker and D. Stanford, Black holes and the but- terfly effect, Journal of High Energy Physics 2014, 1 (2014)
2014
-
[43]
D. A. Roberts, D. Stanford, and L. Susskind, Localized shocks, Journal of High Energy Physics 2015, 1 (2015)
2015
-
[44]
Please see Supplemental Material for additional details
-
[45]
D. D. Awschalom, R. Hanson, J. Wrachtrup, and B. B. Zhou, Quantum technologies with optically interfaced solid-state spins, Nature Photonics 12, 516 (2018)
2018
-
[46]
J. M. Taylor, P. Cappellaro, L. Childress, L. Jiang, D. Budker, P. Hemmer, A. Yacoby, R. Walsworth, and M. Lukin, High-sensitivity diamond magnetometer with nanoscale resolution, Nature Physics 4, 810 (2008)
2008
-
[47]
Castelletto, C
S. Castelletto, C. Lew, W.-X. Lin, and J.-S. Xu, Quan- tum systems in silicon carbide for sensing applications, Reports on Progress in Physics (2023)
2023
-
[48]
S. L. Braunstein and C. M. Caves, Statistical distance and the geometry of quantum states, Physical Review Letters 72, 3439 (1994)
1994
-
[49]
spin up” state, and |1⟩ is the “spin down
For spin-1/2 particles, we adopt the convention that |0⟩ is the “spin up” state, and |1⟩ is the “spin down” state; i.e., σz|0⟩ =|0⟩ and σz|1⟩ =−| 1⟩
-
[50]
Bouwmeester, J.-W
D. Bouwmeester, J.-W. Pan, M. Daniell, H. Wein- furter, and A. Zeilinger, Observation of three-photon greenberger-horne-zeilinger entanglement, Physical Re- view Letters 82, 1345 (1999)
1999
-
[51]
We note that the quantum circuit implementing this approach [i.e. Fig. 1(a)] is closely related to the one- sided implementation of the teleportation circuit shown in Ref. [54]
-
[52]
K. A. Landsman, C. Figgatt, T. Schuster, N. M. Linke, B. Yoshida, N. Y. Yao, and C. Monroe, Verified quantum information scrambling, Nature 567, 61 (2019)
2019
-
[53]
M. S. Blok, V. V. Ramasesh, T. Schuster, K. O’Brien, J.-M. Kreikebaum, D. Dahlen, A. Morvan, B. Yoshida, N. Y. Yao, and I. Siddiqi, Quantum information scram- bling on a superconducting qutrit processor, Physical Re- view X 11, 021010 (2021)
2021
-
[54]
Schuster, B
T. Schuster, B. Kobrin, P. Gao, I. Cong, E. T. Khabi- boulline, N. M. Linke, M. D. Lukin, C. Monroe, B. Yoshida, and N. Y. Yao, Many-body quantum telepor- tation via operator spreading in the traversable wormhole protocol, Physical Review X 12, 031013 (2022)
2022
-
[55]
Zhou and B
T. Zhou and B. Swingle, Operator growth from global out-of-time-order correlators, Nature communications 14, 3411 (2023)
2023
-
[56]
Maldacena, S
J. Maldacena, S. H. Shenker, and D. Stanford, A bound on chaos, Journal of High Energy Physics2016, 1 (2016)
2016
-
[57]
Sekino and L
Y. Sekino and L. Susskind, Fast scramblers, Journal of High Energy Physics 2008, 065 (2008)
2008
-
[58]
D. Hume, I. Stroescu, M. Joos, W. Muessel, H. Strobel, and M. Oberthaler, Accurate atom counting in meso- scopic ensembles, Physical review letters 111, 253001 (2013)
2013
-
[59]
M. W. Doherty, N. B. Manson, P. Delaney, F. Jelezko, J. Wrachtrup, and L. C. Hollenberg, The nitrogen- vacancy colour centre in diamond, Physics Reports 528, 1 (2013)
2013
-
[60]
Cooper, W
A. Cooper, W. K. C. Sun, J.-C. Jaskula, and P. Cap- pellaro, Environment-assisted quantum-enhanced sens- ing with electronic spins in diamond, Physical Review Applied 12, 044047 (2019)
2019
-
[61]
Degen, S
M. Degen, S. Loenen, H. Bartling, C. Bradley, A. Meinsma, M. Markham, D. Twitchen, and T. Taminiau, Entanglement of dark electron-nuclear spin defects in diamond, Nature Communications 12, 3470 (2021)
2021
-
[62]
Schirhagl, K
R. Schirhagl, K. Chang, M. Loretz, and C. L. Degen, Nitrogen-vacancy centers in diamond: nanoscale sensors for physics and biology, Annual review of physical chem- istry 65, 83 (2014)
2014
-
[63]
J. F. Barry, M. J. Turner, J. M. Schloss, D. R. Glenn, Y. Song, M. D. Lukin, H. Park, and R. L. Walsworth, Optical magnetic detection of single-neuron action po- tentials using quantum defects in diamond, Proceedings of the National Academy of Sciences 113, 14133 (2016)
2016
-
[64]
Schlussel, T
Y. Schlussel, T. Lenz, D. Rohner, Y. Bar-Haim, L. Bougas, D. Groswasser, M. Kieschnick, E. Rozenberg, L. Thiel, A. Waxman, et al., Wide-field imaging of super- conductor vortices with electron spins in diamond, Phys- ical Review Applied 10, 034032 (2018)
2018
-
[65]
L. Hall, P. Kehayias, D. Simpson, A. Jarmola, A. Stacey, D. Budker, and L. Hollenberg, Detection of nanoscale electron spin resonance spectra demonstrated using nitrogen-vacancy centre probes in diamond, Nature com- munications 7, 10211 (2016)
2016
-
[66]
C. Zu, F. Machado, B. Ye, S. Choi, B. Kobrin, T. Mittiga, S. Hsieh, P. Bhattacharyya, M. Markham, D. Twitchen, et al., Emergent hydrodynamics in a strongly interacting dipolar spin ensemble, Nature 597, 45 (2021)
2021
-
[67]
J. Choi, H. Zhou, H. S. Knowles, R. Landig, S. Choi, and M. D. Lukin, Robust dynamic hamiltonian engineering of many-body spin systems, Physical Review X 10, 031002 (2020)
2020
-
[68]
Belthangady, N
C. Belthangady, N. Bar-Gill, L. M. Pham, K. Arai, D. Le Sage, P. Cappellaro, and R. L. Walsworth, Dressed- state resonant coupling between bright and dark spins in diamond, Physical review letters 110, 157601 (2013)
2013
-
[69]
Kucsko, S
G. Kucsko, S. Choi, J. Choi, P. C. Maurer, H. Zhou, R. Landig, H. Sumiya, S. Onoda, J. Isoya, F. Jelezko, et al., Critical thermalization of a disordered dipolar spin system in diamond, Physical review letters 121, 023601 (2018)
2018
-
[70]
De Lange, Z
G. De Lange, Z. Wang, D. Riste, V. Dobrovitski, and R. Hanson, Universal dynamical decoupling of a single solid-state spin from a spin bath, Science 330, 60 (2010)
2010
-
[71]
C. Chen, G. Bornet, M. Bintz, G. Emperauger, 8 L. Leclerc, V. S. Liu, P. Scholl, D. Barredo, J. Hauschild, S. Chatterjee, et al., Continuous symmetry breaking in a two-dimensional rydberg array, Nature 616, 691 (2023)
2023
-
[72]
Periwal, E
A. Periwal, E. S. Cooper, P. Kunkel, J. F. Wienand, E. J. Davis, and M. Schleier-Smith, Programmable in- teractions and emergent geometry in an array of atom clouds, Nature 600, 630 (2021)
2021
-
[73]
Braum¨ uller, A
J. Braum¨ uller, A. H. Karamlou, Y. Yanay, B. Kannan, D. Kim, M. Kjaergaard, A. Melville, B. M. Niedzielski, Y. Sung, A. Veps¨ al¨ ainen,et al., Probing quantum infor- mation propagation with out-of-time-ordered correlators, Nature Physics 18, 172 (2022)
2022
-
[74]
Pogorelov, T
I. Pogorelov, T. Feldker, C. D. Marciniak, L. Postler, G. Jacob, O. Krieglsteiner, V. Podlesnic, M. Meth, V. Negnevitsky, M. Stadler, et al. , Compact ion-trap quantum computing demonstrator, PRX Quantum 2, 020343 (2021)
2021
-
[75]
L. Egan, D. M. Debroy, C. Noel, A. Risinger, D. Zhu, D. Biswas, M. Newman, M. Li, K. R. Brown, M. Cetina, et al., Fault-tolerant control of an error-corrected qubit, Nature 598, 281 (2021)
2021
-
[76]
Chen and T
X. Chen and T. Zhou, Quantum chaos dynamics in long- range power law interaction systems, Physical Review B 100, 064305 (2019)
2019
-
[77]
T. Zhou, S. Xu, X. Chen, A. Guo, and B. Swingle, Op- erator l´ evy flight: Light cones in chaotic long-range in- teracting systems, Physical review letters 124, 180601 (2020)
2020
-
[78]
For the global protocol, we plot the metrological gain, instead of the sensitivity, since the global protocol has a sensitivity given by the SQL at time zero
-
[79]
We note that this suppression factor is precisely the square of the so-called Loschmidt echo [80]
-
[80]
Schuster and N
T. Schuster and N. Y. Yao, Operator growth in open quantum systems, Physical Review Letters 131, 160402 (2023)
2023
-
[81]
Hyllus, W
P. Hyllus, W. Laskowski, R. Krischek, C. Schwem- mer, W. Wieczorek, H. Weinfurter, L. Pezz´ e, and A. Smerzi, Fisher information and multiparticle entan- glement, Physical Review A 85, 022321 (2012)
2012
-
[82]
G¨ uhne and G
O. G¨ uhne and G. T´ oth, Entanglement detection, Physics Reports 474, 1 (2009)
2009
-
[83]
Krinner, S
S. Krinner, S. Lazar, A. Remm, C. K. Andersen, N. Lacroix, G. J. Norris, C. Hellings, M. Gabureac, C. Eichler, and A. Wallraff, Benchmarking coherent er- rors in controlled-phase gates due to spectator qubits, Physical Review Applied 14, 024042 (2020)
2020
-
[84]
Z. Li, S. Colombo, C. Shu, G. Velez, S. Pilatowsky- Cameo, R. Schmied, S. Choi, M. Lukin, E. Pedrozo- Pe˜ nafiel, and V. Vuleti´ c, Improving metrology with quan- tum scrambling, Science 380, 1381 (2023). Supplemental Material: A Universal Protocol for Quantum-Enhanced Sensing...
2023 arXiv
-
[85]
un-squeeze
The full sensing scheme consists of applying U to generate a GHZ state, accumulating a phase under the external signal, and then applying the inverse preparation circuit to refocus the acquired phase to a single-body observable. This last step is not strictly necessary—one cou...
-
[86]
butterfly
In Fig. 4(b) of the main text, we compare this prediction to the sensitivities obtained in exact numerical simulations of a spin model with N = 18 spins and observe excellent agreement. We remark that, interestingly, measuring the global spin operator, Sx, is in some cases not...
-
[87]
This is achieved for the NV centers via optical polarization and for the P1 centers via cyrogenic conditions
Initialize in a fully polarized state in the Z direction. This is achieved for the NV centers via optical polarization and for the P1 centers via cyrogenic conditions
-
[88]
Rotate the state to the X direction by applying a microwave pulse resonant with (a) the two levels of the P1 center, and (b) the|ms = 0⟩↔| ms =−1⟩ transition of the NV center
-
[89]
8 (a) (b) (c) (d) Metrological Gain 1/φ tτ Metrological Gain tτ tτ 1/φ tτ Circuit layers 1/φ σ = } } Layer 1 Layer 2 FIG
Evolve under the engineered Hamiltonian ˜H+ by applying the pulse sequence described above. 8 (a) (b) (c) (d) Metrological Gain 1/φ tτ Metrological Gain tτ tτ 1/φ tτ Circuit layers 1/φ σ = } } Layer 1 Layer 2 FIG. S4. Numerical simulations of our protocol with four proposed ex...
-
[90]
The steps up to this point produce the butterfly state
Apply a local rotation to the NV and evolve backwards under− ˜H+. The steps up to this point produce the butterfly state
-
[91]
Apply the global sensing signal e−iϕSz, where Sz =sz + ∑ ipi z
-
[92]
Evolve forward again under ˜H+, and measure the polarization of the NV center using optical excitation. We emphasize that the protocol succeeds despite the presence of strong positional disorder in the spin system: Any position configurations would lead to many-body interactio...
-
[93]
Optically polarize the NV centers into the |0⟩ state
-
[94]
Rotate the state via a pi/2 pulse in the subspace {|0⟩,|−1⟩}
-
[95]
Evolve under the average Hamiltonian ˜H by alternating between the {|0⟩,|−1⟩} subspace and {|−1⟩,|1⟩} subspace
-
[96]
Apply a small global rotation to the NV centers, eiϵSx, where the angle ϵ is optimized as function of the evolution time
-
[97]
S3 within each subspace
Evolve backwards under− ˜H by (a) alternating between the two subspaces and (b) applying the pulse sequence shown in Fig. S3 within each subspace
-
[98]
Apply the global sensing signal e−iϕSz, where Sz = ∑ isi z
-
[99]
subspace engineering
Evolve forward again under ˜H, and measure the total polarization of the NV centers via optical excitation. To our knowledge, implementing time reversal by applying pulse engineering sequences to multiple sub- spaces has not been previously proposed. Successfully demonstrating...
-
[100]
The bitstringbi is immediately given by flipping a on the ith bit
Sample a from a binomial distribution andi from a uniform distribution. The bitstringbi is immediately given by flipping a on the ith bit
-
[101]
Compute ϕab =ϕ(Sz{U†PaU}−S z{U†PbU}) by time evolving Xa and Xb under a Clifford circuit
-
[102]
contract
Average the quantity (i tanϵ)|bi|−|a|eiϕabi over many samples. We estimate the sensitivity via η−1 ϕ=0≡ (∂ϕ⟨Sx⟩ϕ/∆Sx,ϕ)ϕ=0≈⟨ Sx⟩ϕ/ √ N, where ϕ≪ 1, and for circuits with Haar-random gates, on average, ⟨Sx⟩ϕ=0 and (∆Sx)ϕ=0 = √ N/2. To benchmark the stochastic model, we calculat...
-
[103]
Davis, G
E. Davis, G. Bentsen, and M. Schleier-Smith, Physical review letters 116, 053601 (2016)
2016
-
[104]
Macr` ı, A
T. Macr` ı, A. Smerzi, and L. Pezz` e, Physical Review A94, 010102 (2016)
2016
-
[105]
G. J. Mooney, G. A. White, C. D. Hill, and L. C. Hollenberg, Journal of Physics Communications 5, 095004 (2021)
2021
-
[106]
Z. Li, S. Colombo, C. Shu, G. Velez, S. Pilatowsky-Cameo, R. Schmied, S. Choi, M. Lukin, E. Pedrozo-Pe˜ nafiel, and V. Vuleti´ c, Science380, 1381 (2023)
2023
-
[107]
Colombo, E
S. Colombo, E. Pedrozo-Pe˜ nafiel, A. F. Adiyatullin, Z. Li, E. Mendez, C. Shu, and V. Vuleti´ c, Nature Physics 18, 925 (2022)
2022
-
[108]
Goldstein, P
G. Goldstein, P. Cappellaro, J. R. Maze, J. Hodges, L. Jiang, A. S. Sørensen, and M. Lukin, Physical review letters 106, 140502 (2011)
2011
-
[109]
Block, B
M. Block, B. Ye, B. Roberts, S. Chern, W. Wu, Z. Wang, L. Pollet, E. J. Davis, B. I. Halperin, and N. Y. Yao, arXiv preprint arXiv:2301.09636 (2023)
2023 arXiv
-
[110]
Khemani, A
V. Khemani, A. Vishwanath, and D. A. Huse, Physical Review X 8, 031057 (2018)
2018
-
[111]
C. Chen, G. Bornet, M. Bintz, G. Emperauger, L. Leclerc, V. S. Liu, P. Scholl, D. Barredo, J. Hauschild, S. Chatterjee, et al. , Nature 616, 691 (2023)
2023
-
[112]
Bornet, G
G. Bornet, G. Emperauger, C. Chen, B. Ye, M. Block, M. Bintz, J. A. Boyd, D. Barredo, T. Comparin, F. Mezzacapo, et al. , arXiv preprint arXiv:2303.08053 (2023)
2023 arXiv
-
[113]
A. V. Gorshkov, S. R. Manmana, G. Chen, E. Demler, M. D. Lukin, and A. M. Rey, Physical Review A—Atomic, Molecular, and Optical Physics 84, 033619 (2011)
2011
-
[114]
De L´ es´ eleuc, D
S. De L´ es´ eleuc, D. Barredo, V. Lienhard, A. Browaeys, and T. Lahaye, Physical Review A97, 053803 (2018)
2018
-
[115]
C. Zu, F. Machado, B. Ye, S. Choi, B. Kobrin, T. Mittiga, S. Hsieh, P. Bhattacharyya, M. Markham, D. Twitchen, et al. , Nature 597, 45 (2021)
2021
-
[116]
Jarmola, V
A. Jarmola, V. Acosta, K. Jensen, S. Chemerisov, and D. Budker, Physical review letters 108, 197601 (2012)
2012
-
[117]
J. Choi, H. Zhou, H. S. Knowles, R. Landig, S. Choi, and M. D. Lukin, Physical Review X 10, 031002 (2020)
2020
-
[118]
Kucsko, S
G. Kucsko, S. Choi, J. Choi, P. C. Maurer, H. Zhou, R. Landig, H. Sumiya, S. Onoda, J. Isoya, F. Jelezko, et al., Physical review letters 121, 023601 (2018)
2018
-
[119]
Pedrozo-Pe˜ nafiel, S
E. Pedrozo-Pe˜ nafiel, S. Colombo, C. Shu, A. F. Adiyatullin, Z. Li, E. Mendez, B. Braverman, A. Kawasaki, D. Akamatsu, Y. Xiao, et al. , Nature 588, 414 (2020)
2020
-
[120]
V. D. Vaidya, Y. Guo, R. M. Kroeze, K. E. Ballantine, A. J. Koll´ ar, J. Keeling, and B. L. Lev, Physical Review X 8, 011002 (2018)
2018
-
[121]
Periwal, E
A. Periwal, E. S. Cooper, P. Kunkel, J. F. Wienand, E. J. Davis, and M. Schleier-Smith, Nature 600, 630 (2021)
2021
-
[122]
Bentsen, T
G. Bentsen, T. Hashizume, A. S. Buyskikh, E. J. Davis, A. J. Daley, S. S. Gubser, and M. Schleier-Smith, Physical review letters 123, 130601 (2019)
2019
-
[123]
Swingle, G
B. Swingle, G. Bentsen, M. Schleier-Smith, and P. Hayden, Physical Review A 94, 040302 (2016)
2016
-
[124]
Arute, K
F. Arute, K. Arya, R. Babbush, D. Bacon, J. C. Bardin, R. Barends, R. Biswas, S. Boixo, F. G. Brandao, D. A. Buell, et al. , Nature 574, 505 (2019)
2019
-
[125]
Y. Kim, A. Eddins, S. Anand, K. X. Wei, E. Van Den Berg, S. Rosenblatt, H. Nayfeh, Y. Wu, M. Zaletel, K. Temme, et al. , Nature 618, 500 (2023)
2023
-
[126]
Braum¨ uller, A
J. Braum¨ uller, A. H. Karamlou, Y. Yanay, B. Kannan, D. Kim, M. Kjaergaard, A. Melville, B. M. Niedzielski, Y. Sung, A. Veps¨ al¨ ainen,et al. , Nature Physics 18, 172 (2022)
2022
-
[127]
T. I. Andersen, N. Astrakhantsev, A. Karamlou, J. Berndtsson, J. Motruk, A. Szasz, J. A. Gross, T. Westerhout, Y. Zhang, E. Forati, et al. , arXiv preprint arXiv:2405.17385 (2024)
2024 arXiv
-
[128]
Foxen, C
B. Foxen, C. Neill, A. Dunsworth, P. Roushan, B. Chiaro, A. Megrant, J. Kelly, Z. Chen, K. Satzinger, R. Barends, et al. , Physical Review Letters 125, 120504 (2020)
2020
-
[129]
Rosenberg, T
E. Rosenberg, T. Andersen, R. Samajdar, A. Petukhov, J. Hoke, D. Abanin, A. Bengtsson, I. Drozdov, C. Er- 18 ickson, P. Klimov, et al. , arXiv preprint arXiv:2306.09333 (2023)
2023 arXiv
-
[130]
Z. Bao, S. Xu, Z. Song, K. Wang, L. Xiang, Z. Zhu, J. Chen, F. Jin, X. Zhu, Y. Gao, et al. , arXiv preprint arXiv:2401.08284 (2024)
2024 arXiv
-
[131]
X. Mi, P. Roushan, C. Quintana, S. Mandra, J. Marshall, C. Neill, F. Arute, K. Arya, J. Atalaya, R. Babbush, et al. , Science 374, 1479 (2021)
2021
-
[132]
Pogorelov, T
I. Pogorelov, T. Feldker, C. D. Marciniak, L. Postler, G. Jacob, O. Krieglsteiner, V. Podlesnic, M. Meth, V. Negnevitsky, M. Stadler, et al. , PRX Quantum 2, 020343 (2021)
2021
-
[133]
L. Egan, D. M. Debroy, C. Noel, A. Risinger, D. Zhu, D. Biswas, M. Newman, M. Li, K. R. Brown, M. Cetina, et al. , Nature 598, 281 (2021)
2021
-
[134]
Chen and T
X. Chen and T. Zhou, Physical Review B 100, 064305 (2019)
2019
-
[135]
T. Zhou, S. Xu, X. Chen, A. Guo, and B. Swingle, Physical review letters 124, 180601 (2020)
2020
-
[136]
Zhou and B
T. Zhou and B. Swingle, Nature communications 14, 3411 (2023)
2023
-
[137]
Nahum, S
A. Nahum, S. Vijay, and J. Haah, Physical Review X 8, 021014 (2018)
2018
-
[138]
Webb, arXiv preprint arXiv:1510.02769 (2015)
Z. Webb, arXiv preprint arXiv:1510.02769 (2015)
2015 arXiv
- [139]
-
[140]
Zhu, Physical Review A 96, 062336 (2017)
H. Zhu, Physical Review A 96, 062336 (2017)
2017
-
[141]
Schuster and N
T. Schuster and N. Y. Yao, Physical Review Letters 131, 160402 (2023)
2023
Reviewed August 12, 2026 · model on record in the stance chip above.
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