Skip to main content

Generic Laplacian eigenfunctions on metric graphs

Abstract

It is known that up to certain pathologies, a compact metric graph with standard vertex conditions has a Baire-generic set of choices of edge lengths such that all Laplacian eigenvalues are simple and have eigenfunctions that do not vanish at the vertices, [16, 12]. We provide a new notion of strong genericity, using subanalytic sets, that implies both Baire genericity and full Lebesgue measure. We show that the previous genericity results for metric graphs are strongly generic. In addition, we show that generically the derivative of an eigenfunction does not vanish at the vertices either. In fact, we show that generically an eigenfunction fails to satisfy any additional vertex condition. Finally, we show that any two different metric graphs with the same edge lengths do not share any non-zero eigenvalue, for a generic choice of lengths, except for a few explicit cases where the graphs have a common edge-reflection symmetry. The paper concludes by addressing three open conjectures for metric graphs that can benefit from the tools introduced in this paper.

This is a preview of subscription content, access via your institution.

References

  1. J. Agler, J. E. McCarthy and M. Stankus, Toral algebraic sets and function theory on polydisks, J. Geom. Anal. 16 (2006), 551–562.

    Article  MathSciNet  MATH  Google Scholar 

  2. J. H. Albert, Topology of the Nodal and Critical Point Sets for Eigenfunctions of Elliptic Operators, Ph.D. Thesis, Massachusetts Institute of Technology, Cambridge, MA, 1971.

    Google Scholar 

  3. L. Alon, Quantum graphs-generic eigenfunctions and their nodal Count and Neumann count statistics, arXiv:2010.03004 [math-ph].

  4. L. Alon, R. Band and G. Berkolaiko, Nodal statistics on Quantum graphs, Comm. Math. Phys. 362 (2018), 909–948.

    Article  MathSciNet  MATH  Google Scholar 

  5. L. Alon, R. Band and G. Berkolaiko, Universality of nodal count distribution in large metric graphs, Exp. Math. (2022), 1–35.

  6. R. Band, G. Berkolaiko and T. Weyand, Anomalous nodal count and singularities in the dispersion relation of honeycomb graphs, J. Math. Phys. 56 (2015), Article no. 122111.

  7. R. Band and G. Lévy, Quantum graphs which optimize the spectral gap, Ann. Henri Poincaré 18 (2017), 3269–3323.

    Article  MathSciNet  MATH  Google Scholar 

  8. F. Barra and P. Gaspard, On the level spacing distribution in quantum graphs, J. Statist. Phys. 101 (2000), 283–319.

    Article  MathSciNet  MATH  Google Scholar 

  9. G. Berkolaiko, A lower bound for nodal count on discrete and metric graphs, Comm. Math. Phys. 278 (2008), 803–819.

    Article  MathSciNet  MATH  Google Scholar 

  10. G. Berkolaiko and P. Kuchment, Introduction to Quantum Graphs, American Mathematical Society, Providence, RI, 2013.

    MATH  Google Scholar 

  11. G. Berkolaiko, Y. Latushkin and S. Sukhtaiev, Limits of quantum graph operators with shrinking edges, Adv. Math. 352 (2019), 632–669.

    Article  MathSciNet  MATH  Google Scholar 

  12. G. Berkolaiko and W. Liu, Simplicity of eigenvalues and non-vanishing of eigenfunctions of a quantum graph, J. Math. Anal. Appl. 445 (2017), 803–818.

    Article  MathSciNet  MATH  Google Scholar 

  13. G. Berkolaiko and B. Winn, Relationship between scattering matrix and spectrum of quantum graphs, Trans. Amer. Math. Soc. 362 (2010), 6261–6277.

    Article  MathSciNet  MATH  Google Scholar 

  14. E. Bierstone and P. D. Milman, Semianalytic and subanalytic sets, Inst. Hautes Etudes Sci. Publ. Math. 67 (1988), 5–42.

    Article  MathSciNet  MATH  Google Scholar 

  15. Y. Colin de Verdière, Semi-classical measures on quantum graphs and the Gauß map of the determinant manifold, Ann. Henri Poincaré 16 (2015), 347–364.

    Article  MathSciNet  MATH  Google Scholar 

  16. L. Friedlander, Genericity of simple eigenvalues for a metric graph, Israel J. Math. 146 (2005), 149–156.

    Article  MathSciNet  MATH  Google Scholar 

  17. A. M. Gabriélov, Projections of semi-analytic sets, Funct. Anal. Appl. 2 (1968), 282–291.

    Article  MATH  Google Scholar 

  18. S. Gnutzmann, J. P. Keating and F. Piotet, Eigenfunction statistics on quantum graphs, Ann. Physics 325 (2010), 2595–2640.

    Article  MathSciNet  MATH  Google Scholar 

  19. S. Gnutzmann and U. Smilansky, Quantum graphs: Applications to quantum chaos and universal spectral statistics, Adv. Phys. 55 (2006), 527–625.

    Article  Google Scholar 

  20. S. Gnutzmann, U. Smilansky and J. Weber, Nodal counting on quantum graphs, Waves Random Media 14 (2004), S61–S73.

    Article  MathSciNet  MATH  Google Scholar 

  21. B. Gutkin and U. Smilansky, Can one hear the shape of a graph?, J. Phys. A 34 (2001), 6061–6068.

    Article  MathSciNet  MATH  Google Scholar 

  22. L. Hillairet and C. Judge, Generic spectral simplicity of polygons, Proc. Amer. Math. Soc. 137 (2009), 2139–2145.

    Article  MathSciNet  MATH  Google Scholar 

  23. L. Hillairet and C. Judge, Hyperbolic triangles without embedded eigenvalues, Ann. of Math. (2) 187 (2018), 301–377.

    Article  MathSciNet  MATH  Google Scholar 

  24. M. Hofmann, J. B. Kennedy, D. Mugnolo and M. Plümer, On pleijel’s nodal domain theorem for quantum graphs, Ann. Henri Poincaré 22 (2021), 3841–3870.

    Article  MathSciNet  MATH  Google Scholar 

  25. T. Kottos and U. Smilansky, Quantum chaos on graphs, Phys. Rev. Lett. 79 (1997), 4794–4797.

    Article  Google Scholar 

  26. P. Kurasov, Spectral Geometry of Graphs, Birkhäuser, Berlin–Heidelberg, 2023.

    Google Scholar 

  27. P. Kurasov and M. Nowaczyk, Inverse spectral problem for quantum graphs, J. Phys. A 38 (2005), 4901–4915.

    Article  MathSciNet  MATH  Google Scholar 

  28. P. Kurasov and P. Sarnak, Stable polynomials and crystalline measures, J. Math. Phys. 61 (2020), Article no. 083501.

  29. P. Kurasov and P. Sarnak, The additive structure of the spectrum of the laplacian on a metric graph, in preparation.

  30. M. Plümer and M. Täufer, On fully supported eigenfunctions of quantum graphs, Lett. Math. Phys. 111 (2021), Article no. 153.

  31. K. Uhlenbeck, Eigenfunctions of Laplace operators, Bull. Amer. Math. Soc. 78 (1972), 1073–1076.

    Article  MathSciNet  MATH  Google Scholar 

  32. L. Van den Dries and C. Miller, Geometric categories and o-minimal structures, Duke Math. J. 84 (1996), pp. 497–540.

    Article  MathSciNet  MATH  Google Scholar 

Download references

Acknowledgments

The author would like to thank Peter Sarnak, Mark Goresky, Karen Uhlenbeck, Pavel Kurasov, and Ram Band for insightful discussions, important remarks and relevant references. The author was supported by the Ambrose Monell Foundation and the Institute for Advanced Study.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Lior Alon.

Rights and permissions

Reprints and Permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Alon, L. Generic Laplacian eigenfunctions on metric graphs. JAMA (2023). https://doi.org/10.1007/s11854-023-0308-x

Download citation

  • Received:

  • Revised:

  • Published:

  • DOI: https://doi.org/10.1007/s11854-023-0308-x