Pith. sign in

REVIEW 3 major objections 5 minor 1 cited by

Phase-locking in dynamical systems and quantum mechanics

T0 review · 3 major / 5 minor · reviewed 2026-08-16 · deepseek-v4-flash

Pith's one-line read Phase-locking domains of Möbius-type torus flows are the instability zones of a single Hill equation, uniting Shapiro steps, Hannay angles, and quantized bands.

desk verdict A useful dictionary linking Arnold tongues, Hill equations, Hannay angles, and Virasoro orbits, with a clean new identity but an unproven step in the RSJ regime where the potential has poles. read the letter →

arxiv 2504.20181 v1 pith:SD52TXPX submitted 2025-04-28 cond-mat.stat-mech hep-thmath.DSnlin.PSquant-ph

classification cond-mat.stat-mechhep-thmath.DSnlin.PSquant-ph MSC 37E4534B3081Q2070H11
keywords phaselockingArnoldtonguesHillequationrotationnumberquantizationHannayangleMilneexactWKBVirasorocoadjointorbits
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

The paper argues that phase-locking in a class of torus flows is not a separate phenomenon but a shadow of one second-order periodic operator. Through the Prüfer transform, a flow on the two-torus with integer-only rotation numbers is equivalent to a Hill equation; the paper claims that phase-locking domains are exactly the instability zones of that Hill operator, that the rotation number equals the non-adiabatic Hannay angle of the associated parametric oscillator in stable zones, and that integer rotation numbers are band indices of a periodic Schrödinger problem via Milne quantization. If this is right, the same dictionary organizes Shapiro steps in Josephson junctions, Arnold tongues, geometric phases, and WKB band-gap data. The paper also assigns each phase-locking domain a Virasoro coadjoint-orbit type, giving a Lie-algebraic classification of the staircase.

What carries the argument

The load-bearing device is the Prüfer transform, the radial projection $(u,\dot u)\mapsto \arg(u-i\dot u)$, which converts the Hill equation into a dynamical system on the two-torus. This projection makes the number of zeros of Hill solutions into the rotation number, makes the $SL(2,\mathbb R)$ conjugacy class of the monodromy into the phase-locking type (hyperbolic means locked, elliptic means unlocked, parabolic means boundary), and connects the Ermakov–Pinney solution $w(t)$, through $\theta_H=\int_0^T dt/w(t)^2$, to the Hannay angle and the Milne wavefunction. The same $w$ solves the stabilizer equation for the Virasoro coadjoint orbit, so the orbit classification is carried by the same object, and the complexified slow manifold of the Riccati form of the Hill equation supplies the spectral curve used for exact WKB estimates.

What would settle it

Numerically integrate the RSJ phase equation and the associated Hill equation at parameters with $A>|B+1|$, where the Hill potential in eq. (2.14) has poles, and check whether the rotation number stays exactly constant and integer wherever the Hill monodromy is hyperbolic; a single parameter point where the two disagree would falsify the claimed identification in the region the paper itself flags.

Watch

Extended reading notes

Core claim

The central claim is a three-way identity: the Poincaré rotation number of a Möbius-type flow on the torus, the monodromy and Floquet data of the associated Hill equation, and the quantization data of the corresponding parametric oscillator or periodic Schrödinger equation are the same mathematical object seen from different sides. Concretely, projecting a Hill equation solution through $\xi=\arg(u-i\dot u)$ produces a torus flow, and the paper shows for the RSJ Josephson model and the Mathieu equation that phase-locking domains, where the rotation number is integer, coincide with hyperbolic instability zones of the Hill operator, while elliptic stability zones carry the irrational rotation number given by $\rho=2\theta_H/T$, with $\theta_H$ the non-adiabatic Hannay angle. The same rotation number is identified with the density of states and, through the Milne ansatz, with exact WKB quantization on a spectral curve. Each tongue, boundary, and gap is then labeled by a Virasoro coadjoint orbit: hyperbolic orbits inside tongues, parabolic orbits at boundaries, elliptic orbits between tongues, and degenerate orbits at constrictions.

Load-bearing premise

The whole identification rests on assuming the zero-counting/rotation-number theorem, proved for smooth periodic potentials, also works for the RSJ Hill potential when that potential has poles; the paper flags this but does not prove it.

Editorial extensions

If this is right

  • If the identification is correct, the boundaries of integer Shapiro steps in overdamped Josephson junctions can be computed directly from the stability chart of one Hill equation, including the pole-affected parameter region if the assumed extension holds.
  • Irrational rotation numbers acquire a classical geometric-phase meaning: in elliptic stability zones the rotation number is fixed by the non-adiabatic Hannay angle, so measuring the rotation number of a driven oscillator measures a geometric angle.
  • The Milne and exact-WKB dictionary makes Arnold-tongue widths computable beyond perturbation theory; the paper derives exponentially thin Mathieu tongues with width scaling like $\exp(-8\sqrt A/\omega)$ and connects them to canard-type non-perturbative effects.
  • The Virasoro coadjoint-orbit classification turns the parameter plane into an orbit diagram, labeling each tongue by a pair of invariants, with degenerate $T_{0,n}$ orbits at constriction points where tongues shrink to points.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • The equality $\rho=2\theta_H/T$ suggests a direct experimental test: in an elliptic, non-locking region of a driven Josephson junction, the time-averaged voltage is proportional to the rotation number and should equal the Hannay angle computed from the Ermakov–Pinney solution, making a classical geometric phase measurable in a solid-state device.
  • The canard–instanton identification points to a resurgent structure in slow-fast torus systems: exponentially small tongue widths should be the leading terms of trans-series in the small-frequency parameter, with Stokes phenomena located by the complexified slow manifold.
  • If the Virasoro classification is robust, constriction points sit at degenerate orbits, which predicts their locations from zeros of Bessel functions and connects conformal weights to the RSJ parameter plane; this is a checkable extension the paper does not carry out.
  • The dictionary suggests that rational plateaus of the rotation number could play the role of Chern-number plateaus in a classical analogue of the quantum Hall staircase, but establishing the underlying topological invariant would require a new argument beyond what the paper provides.
Share X Bluesky LinkedIn Reddit HN

Signed reviews

No signed human review yet.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

3 major / 5 minor

Summary. The paper develops a dictionary between dynamical systems on the two-torus of Möbius type, Hill equations, parametric oscillators, and periodic Schrödinger operators. The central construction is the Prüfer transform: a Hill equation is projected to a flow on the torus, and the Poincaré rotation number of that flow is related to the number of zeros of Hill solutions. The authors claim that phase-locking domains coincide with instability zones of the associated Hill equation, that the rotation number equals 2θ_H/T where θ_H is the non-adiabatic Hannay angle of the parametric oscillator (eq. 3.20), and that these domains are classified by Virasoro coadjoint orbits (Table 2). The paper also connects rotation-number quantization to Milne quantization and exact WKB, interprets semiclassical WKB via slow-fast dynamics and canards, and presents the RSJ Josephson-junction model and the Mathieu equation as examples. Numerical band-structure and phase-locking charts are provided for both models.

Significance. If the claims hold, the paper offers a useful unifying view: the same operator controls the rotation number of a torus flow, the Hannay angle of a parametric oscillator, the band-gap structure of a periodic Schrödinger equation, and the Virasoro-orbit classification of the Hill potential. The clean derivation of ρ=2θ_H/T in the elliptic regime, the self-contained proof of the zero-counting/rotation-number relation for smooth potentials (Appendix A), and the explicit elliptic-integral expressions for the Mathieu actions (eq. 6.21) are strengths. The paper is also honest in flagging some of its own limitations. The Virasoro-orbit classification is essentially a relabeling of the known SL(2,R) monodromy classification rather than independent evidence, but it is a useful organizational principle. The main weakness is that the central RSJ example is used in a regime where the Hill potential is singular and the proved correspondence does not apply; a second, independent issue is a factor-of-two inconsistency in the rotation-number conventions in the summary tables.

major comments (3)
  1. [Sec. 2.3 and Sec. 6.3.2, eq. (2.14)] The RSJ Hill potential (2.14) has poles whenever A≥|B+1|, and the paper's own caveat that 'integration over the period should be performed with care' plus the deferral in Sec. 6.3.2 ('accurate and rigorous analysis will be presented elsewhere') show that Theorem 1 of Appendix A, proved for smooth periodic coefficients, has not been extended to this singular case. Domain III (A>B+1), which contains the 'parquet-like tongues with constrictions' that are a distinctive RSJ feature, lies exactly in the singular regime. Since Figures 2-3 and Tables 1-2 present the RSJ example as support for the general phase-locking/instability-zone correspondence, this is a load-bearing gap. The authors should either prove the extension, for instance by a regularization argument showing convergence of monodromy and rotation number for approximating smooth potentials, or explicitly restrict the proved correspondence and the Virasoro classification to the nonsingular domains and present Domain III only as numerical observation.
  2. [Sec. 4.2 and Table 2] The assignment of RSJ potentials to Virasoro coadjoint orbits (T_{Δ,n}, T±,n, T_{α,0}) assumes that the Hill potential is a smooth quadratic differential, so that the stabilizer equation (4.2) and the representative potentials (4.8)-(4.10) are well defined. For the singular RSJ potential, the stabilizer vector field and the orbit classification are not directly defined, and no regularization is supplied. Therefore Table 2's classification of RSJ phase-locking domains is not established, independently of the numerical correspondence. This is a load-bearing issue because the Virasoro classification is advertised in the abstract and conclusion as one of the paper's main results.
  3. [Tables 1-2 and eqs. (2.3), (3.3), (3.20)] There is a factor-of-two inconsistency in the rotation-number convention. Equation (2.3) defines ρ as π times the zero density, which for the example u=sin(nt/2) with period 2π and n zeros gives ρ=n/2 for the ξ-flow; eqs. (3.3)-(3.4) define ρ via φ=2ξ, giving ρ=n; and eq. (3.20) with unit-Wronskian solutions then also gives ρ=n for the same example. Yet Tables 1-2 list ρ=2n for hyperbolic/phase-locking domains, while Sec. 4.2 states that the integer in the constriction condition B=ωk 'is equal to the rotation number.' These statements cannot all be correct. The authors should fix the convention, correct the factor of two in the tables, and state explicitly which rotation number (ξ-flow, φ-flow, or the original RSJ phase average) is being identified with the Hill-instability zones.
minor comments (5)
  1. [Sec. 7] The text twice writes 'Hanney angle' where 'Hannay angle' is meant; this should be corrected.
  2. [Secs. 2.3 and 6.3.1] The numerical results are described as obtained with Julia's DifferentialEquations.jl, but no code, parameter values, or convergence tests are provided; a reproducibility statement or data/code availability note would strengthen the paper.
  3. [Sec. 6.2] The identification of canards with instanton contributions and the claim that the complexified slow manifold coincides with the spectral curve are presented as assertions rather than theorems; the paper should explicitly label this part as a conjecture or physical interpretation, since the deferred rigorous analysis is acknowledged.
  4. [Sec. 6.3.1, eqs. (6.26)-(6.28)] The asymptotic width estimates should state their regime of validity more precisely (for example, fixed N, small ω, and E≈-1), since the text applies them across a range of parameters without specifying where the asymptotic forms are expected to hold.
  5. [Sec. 2.1] The rotation number ρ is defined modulo Z in Sec. 2.1 but then used as a real-valued quantity in later sections; the paper should explicitly state when lifts to R are being used.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: the central Hill-equation/torus correspondence is proved via the Prüfer transform in Appendix A, and the Hannay-angle relation is a direct derivation rather than a fitted input.

full rationale

The paper's central mapping from Hill equations to dynamical systems on the torus is derived from an explicit Prüfer transformation, Eq. (2.5), and the key rotation-number/zero-counting relation is stated as Theorem 1 and proved in Appendix A; no fitted parameter or assumed conclusion is used there. The RSJ Hill potential (2.14) is obtained by explicit variable changes from the RSJ model in Appendix D, and the monodromy/stability charts are computed numerically and compared with independent simulations and experimental data, so the phase-locking/instability correspondence is a benchmarked check rather than a construction. The relation ρ = 2θ_H/T in Eq. (3.20) follows by direct computation from the definitions: θ_H = ∫_0^T dt/w(t)^2 and ρ = 2 lim_{t→∞} (1/t)∫_0^t ds/(u_1^2+u_2^2), with w^2 = u_1^2+u_2^2 in the elliptic case; it is an identity derived from those definitions, not an input disguised as a prediction. The Virasoro coadjoint-orbit classification in Tables 1 and 2 is a translation of the standard SL(2,R) monodromy classification, with the Δ-eigenvalue relations proved in Appendix C, so it is a relabeling but not circular reasoning. Self-citations such as [16,17] are rigorous published results on RSJ/Heun monodromy used as external mathematical facts, not as the sole justification of a load-bearing premise. The paper itself flags the singular RSJ potential for A ≥ |B+1| and defers rigorous analysis; that is a correctness/rigor gap, not circularity. Overall, the derivation chain is self-contained and independently checkable, so no circular step is exhibited.

Assumptions & free parameters 0 free parameters · 7 assumptions · 0 invented entities

The paper's quantitative claims depend on standard ODE/Floquet theory, the known Johnson-Moser rotation number-zero relation, the Virasoro orbit classification borrowed from the literature, and the exact WKB formulas of Dunne-Unsal and Zinn-Justin. No parameters are fitted to data; the only hand-set constants are normalizations (C=1) that do not affect the central identities. The genuinely load-bearing ad hoc assumption is the extension of the correspondence to singular RSJ potentials and the identification of canards with instantons.

assumptions (7)
  • standard math Rotation number of a torus flow equals π times the density of zeros of the corresponding Hill-equation solution.
    Theorem 1 (Appendix A), following Johnson-Moser [24]; foundational for the whole paper.
  • standard math Floquet theory classifies Hill-equation solutions by elliptic/hyperbolic/parabolic monodromy, with hyperbolic monodromy giving instability.
    Used throughout Section 2 and 4 to identify phase-locking domains with instability bands; standard ODE theory.
  • standard math The classification of Virasoro coadjoint orbits by (n, Δ) and the correspondence between stabilizers and EP-equation solutions.
    Borrowed from [46,47,48,50,52]; applied in Section 4 without re-derivation.
  • domain assumption For the RSJ model, the rotation number is integer-quantized (integer-only Shapiro steps).
    Proved in [12]; the paper relies on it to label phase-locking domains.
  • domain assumption The Hill-equation/rotation-number/Floquet correspondence extends to potentials with poles (RSJ potential for A ≥ |B+1|).
    The paper notes the poles in Section 2.3 but does not prove the extension; numerical integration is performed 'with care'.
  • domain assumption Exact WKB quantization conditions (6.25) and gap-width estimates from [71,82] apply to the rescaled Mathieu equation.
    Used in Section 6.3.1 to derive tongue widths; the formulas are quoted from the literature.
  • ad hoc to paper The complexified slow manifold of a slow-fast torus system coincides with the spectral curve of the associated Schrödinger equation, and canards correspond to instanton contributions.
    Central to Section 6; stated as 'we argue' and 'presumably', not demonstrated.

how reviews work

0 comments
Cite this review

Pith. "Pith review of Phase-locking in dynamical systems and quantum mechanics." pith.science (2026). https://pith.science/paper/SD52TXPX

@misc{pith2026250420181,
  author       = {Pith},
  title        = {Pith review of: Phase-locking in dynamical systems and quantum mechanics},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/SD52TXPX}},
  note         = {Machine review of arXiv:2504.20181}
}
read the original abstract

In this study, we discuss the Prufer transform that connects the dynamical system on the torus and the Hill equation, which is interpreted as either the equation of motion for the parametric oscillator or the Schrodinger equation with periodic potential. The structure of phase-locking domains in the dynamical system on torus is mapped into the band-gap structure of the Hill equation. For the parametric oscillator, we provide the relation between the non-adiabatic Hannay angle and the Poincare rotation number of the corresponding dynamical system. In terms of quantum mechanics, the integer rotation number is connected to the quantization number via the Milne quantization approach and exact WKB. Using recent results concerning the exact WKB approach in quantum mechanics, we discuss the possible non-perturbative effects in the dynamical systems on the torus and for parametric oscillator. The semiclassical WKB is interpreted in the framework of a slow-fast dynamical system. The link between the classification of the coadjoint Virasoro orbits and the Hill equation yields a classification of the phase-locking domains in the parameter space in terms of the classification of Virasoro orbits. Our picture is supported by numerical simulations for the model of the Josephson junction and Mathieu equation.

Figures

Figures reproduced from arXiv: 2504.20181 by the authors.

Figure 1
Figure 1. (a) Trajectory C on torus that start at point A and after one period ends at point B, the dashed circle represents the Poincar´e section, (b) Poincar´e map h that maps A ∈ S 1 to the point B ∈ S 1 where f(φ,t) is a smooth function 2π-periodic in each variable. Consider an arbitrary solution φ(t) of equation (2.1), it is uniquely defined by its initial condition φ(t0) = φ0. Note that if φ(t) is a solution, then φ(t +… view at source ↗
Figure 2
Figure 2. Rotation number ρ as the function of B for fixed value of A for the RSJ model. steps. The question was: does this current-voltage graph have only integer steps or non￾integer steps are also possible? For an external current of the form I/Ic = B + A cos ωt (B is the DC component, A cos ωt is the AC component), direct simulations show that the steps are integer only; see [PITH_FULL_IMAGE:figures/full_fig_p009_2.png] view at source ↗
Figure 3
Figure 3. (a) largest Lyapunov exponent chart for the RSJ model, (b) phase-locking domains [PITH_FULL_IMAGE:figures/full_fig_p010_3.png] view at source ↗
Figures from the paper (4 more)
Figure 4
Figure 4. Figure 4: (a) rotation number quantization for Mathieu system ( [PITH_FULL_IMAGE:figures/full_fig_p011_4.png]
Figure 5
Figure 5. Figure 5: Phase-locking domains (shaded) for the Mathieu equation with small frequencies [PITH_FULL_IMAGE:figures/full_fig_p028_5.png]
Figure 6
Figure 6. Figure 6: Left: two integration contours for the Mathieu equation that encircling real and [PITH_FULL_IMAGE:figures/full_fig_p030_6.png]
Figure 7
Figure 7. Figure 7: Arnold tongues for different values of ω. Domain I corresponds to the region below the full red line; domain II corresponds to the region between full & dashed red lines; domain III corresponds to the region above the dashed line (color online) noticed in [14], in the …

Discussion (0). Continue with ORCID to comment.

Forward citations

Cited by 1 Pith paper

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score. Full citation record

  1. Dynamical systems on torus related to general Heun equations: phase-lock areas and constriction breaking

    math.DS 2025-07 conditional novelty 7.0 of 10

    A deformed RSJ model related to general Heun equations keeps integer-only phase-lock areas while breaking all constrictions.

Reference graph

Works this paper leans on

122 extracted references · 50 canonical work pages · cited by 1 Pith paper

  1. [1]

    Pikovsky, M

    A. Pikovsky, M. Rosenblum, and J. Kurths. Synchronization: A Universal Concept in Nonlinear Sciences. Cambridge University Press, 2001.doi:10.1017/CBO9780511755743

  2. [2]

    D. E. McCumber. Effect of AC impedance on DC voltage-current characteristics of superconductor weak-link junctions. Journal of Applied Physics, 39(7):3113–3118, 1968. doi:10.1063/1.1656743

  3. [3]

    Mishra, A

    S. Mishra, A. Ryabov, and P. Maass. Phase locking and fractional Shapiro steps in collective dynamics of microparticles. Physical Review Letters, 134(10):107102, 2025. doi:10.1103/PhysRevLett.134. 107102

  4. [4]

    R. C. Dinsmore, M. Bae, and A. Bezryadin. Fractional order Shapiro steps in superconducting nanowires. Applied physics letters, 93(19), 2008. doi:10.1063/1.3012360

  5. [5]

    Gr¨ uner and A

    G. Gr¨ uner and A. Zettl. Charge density wave conduction: A novel collective transport phenomenon in solids. Physics Reports, 119(3):117–232, 1985. doi:10.1016/0370-1573(85)90073-0

  6. [6]

    Reichhardt and J

    С. Reichhardt and J. Olson. Shapiro steps for skyrmion motion on a washboard potential with lon- gitudinal and transverse ac drives.Physical Review B, 92(22):224432, 2015. doi:10.1103/PhysRevB. 92.22443

  7. [7]

    D. J. Thouless, M. Kohmoto, M. P. Nightingale, and M. den Nijs. Quantized Hall conductance in a two- dimensional periodic potential. Physical review letters, 49(6):405, 1982. doi:10.1103/PhysRevLett. 49.405

  8. [8]

    J. E. Avron and R. Seiler. Quantization of the Hall conductance for general, multiparticle Schr¨ odinger hamiltonians. Physical review letters, 54(4):259, 1985. URL: 10.1103/PhysRevLett.54.259, doi: 10.1103/PhysRevLett.54.259

Show all 122 references
  1. [9]

    J. E. Avron, R. Seiler, and P. G. Zograf. Viscosity of quantum Hall fluids.Physical review letters, 75(4):697, 1995. doi:10.1103/PhysRevLett.75.697

  2. [10]

    Flack, A

    A. Flack, A. Gorsky, and S. Nechaev. Generalized Devil’s staircase and RG flows.Nuclear Physics B, 996:116376, 2023. doi:10.1016/j.nuclphysb.2023.116376

  3. [11]

    V. Arnold. Geometrical methods in the theory of ordinary differential equations, volume 250. Springer Science & Business Media, 2012

  4. [12]

    Buchstaber, O

    V. Buchstaber, O. Karpov, and S. Tertychniy. Rotation number quantization effect.Theoretical and Mathematical Physics, 162:211–221, 2010. doi:10.1007/s11232-010-0016-4. 45

  5. [13]

    S. Shapiro. Josephson currents in superconducting tunneling: The effect of microwaves and other observations. Physical Review Letters, 11(2):80, 1963. doi:10.1103/PhysRevLett.11.80

  6. [14]

    M. J. Renne and D. Polder. Some analytical results for the resistively shunted Josephson junction. Revue de physique appliqu´ ee, 9(1):25–28, 1974. doi:10.1051/rphysap:019740090102500

  7. [15]

    J. R. Waldram and P. H. Wu. An alternative analysis of the nonlinear equations of the current-driven Josephsonjunction. Journal of Low Temperature Physics, 47:363–374, 1982.doi:10.1007/BF00683738

  8. [16]

    Buchstaber and A

    V. Buchstaber and A. Glutsyuk. On monodromy eigenfunctions of Heun equations and boundaries of phase-lock areas in a model of overdamped Josephson effect.Proceedings of the Steklov Institute of Mathematics, 297:50–89, 2017. doi:10.1134/S0081543817040046

  9. [17]

    Glutsyuk, V

    A. Glutsyuk, V. Kleptsyn, D. Filimonov, and I. Schurov. On the adjacency quantization in an equation modeling the Josephson effect. Functional Analysis and Its Applications, 48(4):272–285, 2014. doi: 10.1007/s10688-014-0070-z

  10. [18]

    Glutsyuk

    A. Glutsyuk. On constrictions of phase-lock areas in model of overdamped Josephson effect and transition matrix of the double-confluent Heun equation.Journal of Dynamical and Control Systems, 25(3):323–349, 2019. doi:10.1007/s10883-018-9411-1

  11. [19]

    S. I. Tertychniy. The modelling of a Josephson junction and Heun polynomials, 2006.arXiv:math-ph/ 0601064

  12. [20]

    Buchstaber and S

    V. Buchstaber and S. Tertychniy. Explicit solution family for the equation of the resistively shunted Josephson junction model.Theoretical and Mathematical Physics, 176(2):965–986, 2013.doi:10.1007/ s11232-013-0085-2

  13. [21]

    Buchstaber and S

    V. Buchstaber and S. Tertychnyi. Holomorphic solutions of the double confluent Heun equation associ- atedwiththeRJSmodeloftheJosephsonjunction. Theoretical and Mathematical Physics, 182:329–355,

  14. [22]

    Bondeson, E

    A. Bondeson, E. Ott, and Thomas M Antonsen Jr. Quasiperiodically forced damped pendula and Schr¨ odinger equations with quasiperiodic potentials: implications of their equivalence.Physical review letters, 55(20):2103, 1985. doi:10.1103/PhysRevLett.55.2103

  15. [23]

    TheHess-Appelrotcaseandquantizationoftherotation number

    I.A.Bizyaev, A.V.Borisov, andI.S.Mamaev. TheHess-Appelrotcaseandquantizationoftherotation number. Regular and Chaotic Dynamics, 22:180–196, 2017. doi:10.1134/S156035471702006X

  16. [24]

    Johnson and J

    R. Johnson and J. Moser. The rotation number for almost periodic potentials. Communications in Mathematical Physics, 84(3):403–438, 1982. URL: https://doi.org/10.1007/BF01208484, doi: doi.org/10.1007/BF01208484

  17. [25]

    Br´ ezin and C

    E. Br´ ezin and C. Itzykson. Pair production in vacuum by an alternating field.Physical Review D, 2(7):1191, 1970. doi:10.1103/PhysRevD.2.1191

  18. [26]

    V. S. Popov. Pair production in a variable external field (quasiclassical approximation).Soviet Journal of Experimental and Theoretical Physics, 34:709, 1972

  19. [27]

    M. Diener. The canard unchained or how fast/slow dynamical systems bifurcate.The Mathematical Intelligencer, 6(3):38–49, 1984. URL:doi.org/10.1007/BF03024127, doi:10.1007/BF03024127

  20. [28]

    Desroches and M

    M. Desroches and M. R. Jeffrey. Canards and curvature: the “smallness ofε“ in slow-fast dynamics. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 467(2132):2404– 2421, 2011. doi:10.1098/rspa.2011.0053

  21. [29]

    Guckenheimer and Y

    J. Guckenheimer and Y. Ilyashenko. The duck and the devil: canards on the staircase. Moscow Mathematical Journal, 1(1):27–47, 2001. doi:10.17323/1609-4514-2001-1-1-27-47

  22. [30]

    Shchurov

    I. Shchurov. Canard cycles in generic fast-slow systems on the torus. Transactions of the Moscow Mathematical Society, 71:175–207, 2010. doi:10.1090/S0077-1554-2010-00184-7. 46

  23. [31]

    Schurov and N

    I. Schurov and N. Solodovnikov. Duck factory on the two-torus: multiple canard cycles without geometric constraints. Journal of Dynamical and Control Systems, 23:481–498, 2017. doi:10.1007/ s10883-016-9335-6

  24. [32]

    Kleptsyn, O

    V. Kleptsyn, O. Romaskevich, and I. Schurov. Josephson effect and slow-fast systems, 2013.arXiv: 1305.6755

  25. [33]

    Pr¨ ufer

    H. Pr¨ ufer. Neue herleitung der Sturm-Liouvilleschen Reihenentwicklung stetiger funktionen.Mathe- matische Annalen, 95(1):499–518, 1926. doi:10.1007/BF01206624

  26. [34]

    Broer and M

    H. Broer and M. Levi. Geometrical aspects of stability theory for Hill’s equations.Archive for rational mechanics and analysis, 131:225–240, 1995. doi:10.1007/BF00382887

  27. [35]

    Broer and C

    H. Broer and C. Sim´ o. Resonance tongues in Hill’s equations: a geometric approach.Journal of Differential Equations, 166(2):290–327, 2000. doi:10.1006/jdeq.2000.3804

  28. [36]

    Sch¨ on and A

    G. Sch¨ on and A. Zaikin. Quantum coherent effects, phase transitions, and the dissipative dynamics of ultra small tunnel junctions.Physics Reports, 198(5-6):237–412, 1990. doi:10.1016/0370-1573(90) 90156-V

  29. [37]

    Zaikin and D

    A. Zaikin and D. Golubev. Dissipative quantum Mechanics of Nanostructures: Electron Transport, Fluctuations, and Interactions. Jenny Stanford Publishing, 2019. URL: 10.1201/9780429298233, doi:10.1201/9780429298233

  30. [38]

    Chikmagalur and B

    K. Chikmagalur and B. Bassam. An implicit function method for computing the stability boundaries of Hill’s equation, 2024.arXiv:2408.08390

  31. [39]

    Panghotra, B

    R. Panghotra, B. Raes, C. C. de Souza Silva, I. Cools, W. Keijers, J. E. Scheerder, V. V. Moshchalkov, and J. Van de Vondel. Giant fractional Shapiro steps in anisotropic Josephson junction arrays.Com- munications Physics, 3(1):53, 2020. doi:10.1038/s42005-020-0315-5

  32. [40]

    Modelingofrf-biasedoverdamped Josephson junctions

    O.Karpov, V.Buchstaber, S.Tertychniy, J.Niemeyer, andO.Kieler. Modelingofrf-biasedoverdamped Josephson junctions. Journal of Applied Physics, 104(9), 2008. doi:10.1063/1.3008011

  33. [41]

    M. V. Berry and J. H. Hannay. Classical non-adiabatic angles.Journal of Physics A: Mathematical and General, 21(6):L325, 1988. doi:10.1088/0305-4470/21/6/002

  34. [42]

    Aharonov and J

    Y. Aharonov and J. Anandan. Phase change during a cyclic quantum evolution. Physical Review Letters, 58(16):1593, 1987. doi:10.1103/PhysRevLett.58.1593

  35. [43]

    H. R. Lewis Jr. Class of exact invariants for classical and quantum time-dependent harmonic oscillators. Journal of Mathematical Physics, 9(11):1976–1986, 1968. doi:10.1063/1.1664532

  36. [44]

    C. J. Eliezer and A. Gray. A note on the time-dependent harmonic oscillator.SIAM Journal on Applied Mathematics, 30(3):463–468, 1976. doi:10.1137/0130043

  37. [45]

    The nonlinear differential equationy +p(x)y +cy−3 = 0

    Edmund Pinney. The nonlinear differential equationy +p(x)y +cy−3 = 0. Proc. Amer. Math. Soc, 1(681):1, 1950. doi:10.1090/S0002-9939-1950-0037979-4

  38. [46]

    Lazutkin and T

    V. Lazutkin and T. Pankratova. Normal forms and versal deformations for Hill’s equation.Functional Analysis and its applications, 9(4):306–311, 1975. doi:10.1007/BF01075876

  39. [47]

    Kirillov

    A. Kirillov. Orbits of the group of diffeomorphisms of a circle and local Lie superalgebras.Functional Analysis and Its Applications, 15(2):135–137, 1981. doi:10.1007/BF01082289

  40. [48]

    E. Witten. Coadjoint orbits of the Virasoro group.Communications in Mathematical Physics, 114(1):1– 53, 1988. doi:10.1007/BF01218287

  41. [49]

    Balog, L

    J. Balog, L. Feh´ er, and L. Palla. Coadjoint orbits of the Virasoro algebra and the global Liou- ville equation. International Journal of Modern Physics A, 13(02):315–362, 1998. doi:10.1142/ S0217751X98000147. 47

  42. [50]

    Blau and D

    M. Blau and D. R. Youmans.SL(2,R) gauge theory, hyperbolic geometry and Virasoro coadjoint orbits,

  43. [51]

    Klimenko and O

    A. Klimenko and O. Romaskevich. Asymptotic properties of Arnold tongues and Josephson effect,

  44. [52]

    Unterberger

    J. Unterberger. A classification of periodic time-dependent generalized harmonic oscillators using a Hamiltonian action of the Schr¨ odinger–Virasoro group.Confluentes Mathematici, 2(02):217–263, 2010. doi:10.1142/S1793744210000168

  45. [53]

    Alekseev and S

    A. Alekseev and S. Shatashvili. Path integral quantization of the coadjoint orbits of the Virasoro group and 2D-gravity.Nuclear Physics B, 323(3):719–733, 1989. doi:10.1016/0550-3213(89)90130-2

  46. [54]

    P. B. Wiegmann. Multivalued functionals and geometrical approach for quantization of relativistic particles and strings.Nuclear Physics B, 323(2):311–329, 1989.doi:10.1016/0550-3213(89)90144-2

  47. [55]

    Gorsky, B

    A. Gorsky, B. Roy, and K. Selivanov. Large gauge transformations and special orbits of the Virasoro group. Soviet Journal of Experimental and Theoretical Physics Letters, 53:64, 1991

  48. [56]

    Gorsky and A

    A. Gorsky and A. Johansen. Liouville theory and special coadjoint Virasoro orbits. International Journal of Modern Physics A, 10(06):785–799, 1995. doi:10.1142/S0217751X95000371

  49. [57]

    V. V. Bazhanov, S. L. Lukyanov, and A. B. Zamolodchikov. Integrable structure of conformal field theory, quantum KdV theory and thermodynamic Bethe ansatz. Communications in Mathematical Physics, 177(2):381–398, 1996. doi:10.1007/BF02101898

  50. [58]

    S. Novikov. The periodic problem for the Korteweg-de Vries equation.Funktsional’nyi Analiz i ego Prilozheniya, 8(3):54–66, 1974. doi:10.1007/BF01075697

  51. [59]

    Bibilo and A

    Y. Bibilo and A. Glutsyuk. On families of constrictions in model of overdamped Josephson junction and Painlev´ e 3 equation.Nonlinearity, 35(10):5427, 2022. doi:10.1088/1361-6544/ac8aee

  52. [60]

    A. Voros. The return of the quartic oscillator. the complex WKB method.Annales de l’IHP Physique th´ eorique, 39(3):211–338, 1983. URL:http://dml.mathdoc.fr/item/AIHPA_1983__39_3_211_0

  53. [61]

    U. D. Jentschura and J. Zinn-Justin. Instantons in quantum mechanics and resurgent expansions. Physics Letters B, 596(1-2):138–144, 2004. doi:10.1016/j.physletb.2004.06.077

  54. [62]

    Zinn-Justin and U

    J. Zinn-Justin and U. D. Jentschura. Multi-instantons and exact results I: Conjectures, WKB expan- sions, and instanton interactions.Annals of Physics, 313(1):197–267, 2004.doi:10.1016/j.aop.2004. 04.004

  55. [63]

    R. E. Langer. The asymptotic solutions of certain linear ordinary differential equations of the second order. Transactions of the American Mathematical Society, 36(1):90–106, 1934.doi:10.2307/1989709

  56. [64]

    G. Alvarez. Langer-Cherry derivation of the multi-instanton expansion for the symmetric double well. Journal of mathematical physics, 45(8):3095–3108, 2004. doi:10.1063/1.1767988

  57. [65]

    G. V. Dunne and M. ¨Unsal. Uniform WKB, multi-instantons, and resurgent trans-series. Physical Review D, 89(10):105009, 2014. doi:10.1103/PhysRevD.89.105009

  58. [66]

    W. E. Milne. The numerical determination of characteristic numbers.Physical Review, 35(7):863, 1930. doi:10.1103/PhysRev.35.863

  59. [67]

    H. J. Korsch. On Milne’s quantum number function.Physics Letters A, 109(7):313–316, 1985. doi: 10.1016/0375-9601(85)90181-1

  60. [68]

    Grassi, J

    A. Grassi, J. Gu, and M. Mari˜ no. Non-perturbative approaches to the quantum Seiberg-Witten curve. Journal of High Energy Physics, 2020(7):1–51, 2020. doi:10.1007/JHEP07(2020)106

  61. [69]

    Mironov and A

    A. Mironov and A. Morozov. Nekrasov functions and exact Bohr-Sommerfeld integrals.Journal of High Energy Physics, 2010(4):1–15, 2010. doi:10.1007/JHEP04(2010)040. 48

  62. [70]

    Grassi, Y

    A. Grassi, Y. Hatsuda, and M. Mari˜ no. Topological strings from quantum mechanics.Annales Henri Poincar´ e, 17:3177–3235, 2016. doi:10.1007/s00023-016-0479-4

  63. [71]

    G. V. Dunne and M.¨Unsal. WKB and resurgence in the Mathieu equation. InResurgence, physics and numbers, pages 249–298. Springer, 2017.doi:10.1007/978-88-7642-613-1_6

  64. [72]

    Exact WKB analysis and TBA equations

    Katsushi Ito and Hongfei Shu. Exact WKB analysis and TBA equations. InODE/IM correspondence and Quantum Periods, pages 23–73. Springer, 2025.doi:10.1007/978-981-96-0499-9_1

  65. [73]

    Exact WKB analysis and cluster algebras.Journal of Physics A: Mathematical and Theoretical, 47(47):474009, 2014

    Kohei Iwaki and Tomoki Nakanishi. Exact WKB analysis and cluster algebras.Journal of Physics A: Mathematical and Theoretical, 47(47):474009, 2014. doi:10.1088/1751-8113/47/47/474009

  66. [74]

    Del Monte and P

    F. Del Monte and P. Longhi. The threefold way to quantum periods: WKB, TBA equations and q-Painlev´ e.SciPost Physics, 15(3):112, 2023. doi:10.21468/SciPostPhys.15.3.112

  67. [75]

    Gaiotto, G

    D. Gaiotto, G. W. Moore, and A. Neitzke. Spectral networks.Annales Henri Poincar´ e, 14(7):1643– 1731, 2013. doi:10.1007/s00023-013-0239-7

  68. [76]

    J. L. Callot, F. Diener, M. M. Diener, et al. Chasse au canard (premi` ere partie).Collectanea Mathe- matica, pages 37–76, 1981

  69. [77]

    K. U. Kristiansen and P. Szmolyan. A dynamical systems approach to WKB-methods: The simple turning point. Journal of Differential Equations, 406:202–254, 2024. doi:10.1016/j.jde.2024.06. 006

  70. [78]

    K. U. Kristiansen and P. Szmolyan. A dynamical systems approach to WKB-methods: The eigenvalue problem for a single well potential, 2025.arXiv:2501.10707

  71. [79]

    V. S. Popov. Imaginary-time method in quantum mechanics and field theory.Physics of Atomic Nuclei, 68:686–708, 2005. doi:10.1134/1.1903097

  72. [80]

    He and Y

    W. He and Y. Miao. Mathieu equation and elliptic curve.Communications in Theoretical Physics, 58(6):827, 2012. doi:10.1088/0253-6102/58/6/08

  73. [81]

    W. He. Combinatorial approach to Mathieu and Lam´ e equations.Journal of Mathematical Physics, 56(7), 2015. doi:10.1063/1.4926954

  74. [82]

    Basar and G

    G. Basar and G. V. Dunne. Resurgence and the Nekrasov-Shatashvili limit: connecting weak and strong coupling in the Mathieu and Lam´ e systems.Journal of high energy physics, 2015(2):1–49, 2015. doi:10.1007/JHEP02(2015)160

  75. [83]

    J. L. Dunham. The Wentzel-Brillouin-Kramers method of solving the wave equation.Physical Review, 41(6):713, 1932. doi:10.1103/PhysRev.41.713

  76. [84]

    U. P. Sukhatme and M. N. Sergeenko. Semiclassical approximation for periodic potentials, 1999. arXiv:quant-ph/9911026

  77. [85]

    Gorsky, A

    A. Gorsky, A. Milekhin, and N. Sopenko. Bands and gaps in Nekrasov partition function.Journal of High Energy Physics, 2018(1), 2018. doi:10.1007/JHEP01(2018)133

  78. [86]

    Seiberg and E

    N. Seiberg and E. Witten. Electric-magnetic duality, monopole condensation, and confinement in N = 2 supersymmetric Yang-Mills theory. Nuclear Physics B, 426(1):19–52, 1994. doi:10.1016/ 0550-3213(94)90124-4

  79. [87]

    Nekrasov

    N. Nekrasov. Seiberg-Witten prepotential from instanton counting.Advances in Theoretical and Math- ematical Physics, 7(5):831–864, 2003. doi:10.4310/ATMP.2003.v7.n5.a4

  80. [88]

    Quantizationofintegrablesystemsandfourdimensional gaugetheories

    N.NekrasovandS.Shatashvili. Quantizationofintegrablesystemsandfourdimensional gaugetheories. In XVIth International Congress On Mathematical Physics, pages 265–289. World Scientific, 2010. doi:10.1142/9789814304634_0015. 49

  81. [89]

    I. M. Krichever. The τ-function of the universal Whitham hierarchy, matrix models and topological field theories.Communications on Pure and Applied Mathematics, 47(4):437–475, 1994.doi:10.1002/ cpa.3160470403

  82. [90]

    Gorsky, A

    A. Gorsky, A. Marshakov, A. Mironov, and A. Morozov. RG equations from Whitham hierarchy. Nuclear Physics B, 527(3):690–716, 1998. doi:10.1016/S0550-3213(98)00315-0

  83. [91]

    Edelstein, M

    J. Edelstein, M. Marino, and J. Mas. Whitham hierarchies, instanton corrections and soft supersym- metry breaking inN = 2SU(N ) super Yang-Mills theory. Nuclear Physics B, 541(3):671–697, 1999. doi:10.1016/S0550-3213(98)00798-6

  84. [92]

    Codesido, M

    S. Codesido, M. Marino, and R. Schiappa. Non-perturbative quantum mechanics from non-perturbative strings. Annales Henri Poincare, 20:543–603, 2019. doi:10.1007/s00023-018-0751-x

  85. [93]

    Kontsevich and Y

    M. Kontsevich and Y. Soibelman.Wall-crossing structures in Donaldson-Thomas invariants, integrable systems and mirror symmetry, pages 197–308. Springer, 2014.doi:10.1007/978-3-319-06514-4_6

  86. [94]

    Gaiotto, G

    D. Gaiotto, G. W. Moore, and A. Neitzke. Four-dimensional wall-crossing via three-dimensional field theory. Communications in Mathematical Physics , 299(1):163–224, 2010. doi:10.1007/ s00220-010-1071-2

  87. [95]

    Basar, G

    G. Basar, G. V. Dunne, and M.¨Unsal. Quantum geometry of resurgent perturbative/nonperturbative relations. Journal of High Energy Physics, 2017(5):1–56, 2017. doi:10.1007/JHEP05(2017)087

  88. [96]

    ¸ Cavu¸ so˘ glu, C

    A. ¸ Cavu¸ so˘ glu, C. Koz¸ caz, and K. Tezgin. Resurgence of deformed genus-1 curves: A novel P/NP relation, 2024. arXiv:2408.02628

  89. [97]

    Gorsky and A

    A. Gorsky and A. Milekhin. RG-Whitham dynamics and complex Hamiltonian systems. Nuclear Physics B, 895:33–63, 2015. doi:10.1016/j.nuclphysb.2015.03.028

  90. [98]

    S. Gukov. RG flows and bifurcations. Nuclear Physics B, 919:583–638, 2017. doi:10.1016/j. nuclphysb.2017.03.025

  91. [99]

    Russian doll renormalization group and Kosterlitz-Thouless flows

    Andr´ e LeClair, Jos´ e Mar´ia Rom´ an, and Germ´ an Sierra. Russian doll renormalization group and Kosterlitz-Thouless flows. Nucl. Phys. B, 675(3):584–606, 2003. doi:10.1016/j.nuclphysb.2003. 09.032

  92. [100]

    K. M. Bulycheva and A. S. Gorsky. Limit cycles in renormalization group dynamics. Phys. Usp., 57(2):171–182, 2014. doi:10.3367/UFNe.0184.201402g.0182

  93. [101]

    C. B. Jepsen, I. R. Klebanov, and F. K. Popov. RG limit cycles and unconventional fixed points in perturbative QFT. Physical Review D, 103(4):046015, 2021. doi:10.1103/PhysRevD.103.046015

  94. [102]

    Motamarri, I

    V. Motamarri, I. Khaymovich, and A. Gorsky. Refined cyclic renormalization group in Russian doll model. SciPost Physics, 17(6):157, 2024. doi:10.21468/SciPostPhys.17.6.157

  95. [103]

    A. LeClair. Non-perturbative renormalization group for Higgs-like models in 4D, 2025.arXiv:2504. 09327

  96. [104]

    C. B. Jepsen and F. K. Popov. Homoclinic renormalization group flows, or when relevant operators become irrelevant. Physical Review Letters, 127(14):141602, 2021. doi:10.1103/PhysRevLett.127. 141602

  97. [105]

    M. M. Bosschaert, C. B. Jepsen, and F. K. Popov. Chaotic RG flow in tensor models.Physical Review D, 105(6):065021, 2022. doi:10.1103/PhysRevD.105.065021

  98. [106]

    de Boer, E

    J. de Boer, E. Verlinde, and H. Verlinde. On the holographic renormalization group.Journal of High Energy Physics, 2000(08):003, 2000. doi:10.1088/1126-6708/2000/08/003

  99. [107]

    Cherman, D

    A. Cherman, D. Dorigoni, and M. ¨Unsal. Decoding perturbation theory using resurgence: Stokes phenomena, new saddle points and Lefschetz thimbles.Journal of High Energy Physics, 2015(10):1–82,

  100. [108]

    G.Basar, G.V.Dunne, andM. ¨Unsal. Resurgencetheory, ghost-instantons, andanalyticcontinuationof path integrals.Journal of High Energy Physics, 2013(10):1–35, 2013.doi:10.1007/JHEP10(2013)041

  101. [109]

    doi:10.1007/JHEP10(2015)056. 50

  102. [110]

    J. P. Provost and G. Vallee. Riemannian structure on manifolds of quantum states.Communications in Mathematical Physics, 76(3):289–301, 1980. doi:10.1007/BF02193559

  103. [111]

    Aniceto, R

    I. Aniceto, R. Schiappa, and M. Vonk. The resurgence of instantons in string theory, 2013.arXiv: 1106.5922

  104. [112]

    L. F. Alday, D. Gaiotto, and Y. Tachikawa. Liouville correlation functions from four-dimensional gauge theories. Letters in Mathematical Physics, 91(2):167–197, 2010. doi:10.1007/s11005-010-0369-5

  105. [113]

    J. Zak. Berry’s phase for energy bands in solids. Physical review letters, 62(23):2747, 1989. doi: 10.1103/PhysRevLett.62.2747

  106. [114]

    Lisovyy and A

    O. Lisovyy and A. Naidiuk. Perturbative connection formulas for Heun equations.Journal of Physics A: Mathematical and Theoretical, 55(43):434005, 2022. doi:10.1088/1751-8121/ac9ba7

  107. [115]

    Litvinov, S

    A. Litvinov, S. Lukyanov, N. Nekrasov, and A. Zamolodchikov. Classical conformal blocks and Painlev´ e VI. Journal of High Energy Physics, 2014(7):1–20, 2014. doi:10.1007/JHEP07(2014)144

  108. [116]

    Aminov, A

    G. Aminov, A. Grassi, and Y. Hatsuda. Black hole quasinormal modes and Seiberg-Witten theory. Annales Henri Poincare, 23(6):1951–1977, 2022. doi:10.1007/s00023-021-01137-x

  109. [117]

    Zenkevich

    Y. Zenkevich. Nekrasov prepotential with fundamental matter from the quantum spin chain.Physics Letters B, 701(5):630–639, 2011. doi:10.1016/j.physletb.2011.06.030

  110. [118]

    Bonelli, C

    G. Bonelli, C. Iossa, D.P. Lichtig, and A. Tanzini. Exact solution of Kerr black hole perturbations via CFT2 and instanton counting: Greybody factor, quasinormal modes, and Love numbers.Physical Review D, 105(4):044047, 2022. doi:10.1103/PhysRevD.105.044047

  111. [119]

    Aminov, P

    G. Aminov, P. Arnaudo, G. Bonelli, A. Grassi, and A. Tanzini. Black hole perturbation the- ory and multiple polylogarithms. Journal of High Energy Physics , 2023(11):1–61, 2023. doi: 10.1007/JHEP11(2023)059

  112. [120]

    Alexandrov, A

    A. Alexandrov, A. Gorsky, and L. Senchukov. On rotation number quantization and QNM of black holes. In preparation. 51

  113. [121]

    Bonelli, C

    G. Bonelli, C. Iossa, D.P. Lichtig, and A. Tanzini. Irregular Liouville correlators and connection formulae for Heun functions.Communications in Mathematical Physics, 397(2):635–727, 2023. doi: 10.1007/s00220-022-04497-5

  114. [2015]

    doi:10.1007/s11232-015-0267-1

Pith tools

Reviewed August 16, 2026 · model on record in the stance chip above.