Abstract
We develop Darboux transformations (DTs) and their associated Crum’s formulas for two Schrödinger-type difference equations that are themselves discretized versions of the spectral problems of the KdV and modified KdV equations. With DTs viewed as a discretization process, classes of semidiscrete and fully discrete KdV-type systems, including the lattice versions of the potential KdV, potential modified KdV, and Schwarzian KdV equations, arise as the consistency condition for the differential/difference spectral problems and their DTs. The integrability of the underlying lattice models, such as Lax pairs, multidimensional consistency, τ-functions, and soliton solutions, can be easily obtained by directly applying the discrete Crum’s formulas.
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G. Darboux, “Sur une proposition relative aux equations lineaires,” C. R. Acad. Sci. Paris, 94, 1456–1459 (1882).
M. M. Crum, “Associated Sturm—Liouville systems,” Quart. J. Math., 6, 121–127 (1955).
V. B. Matveev and M. A. Salle, Darboux Transformations and Solitons, Springer, Berlin (1991).
A. B. Shabat, “Dressing chains and lattices,” in: Nonlinearity, Integrability, and All That: Twenty Years After NEEDS’79 (Lecce, Italy, 1–10 July 1999, M. Boiti, L. Martina, F. Pempinelly, B. Prinary, and G. Soliani, eds.), World Scientific, Singapore (2000), pp. 341–342.
D. Levi and R. Benguria, “Bäcklund transformations and nonlinear differential difference equations,” Proc. Nat. Acad. Sci. USA, 77, 5025–5027 (1980).
D. Levi, “Nonlinear differential difference equations as Bäcklund transformations,” J. Phys. A: Math. Gen., 14, 1083–1098 (1981).
V. B. Matveev, “Darboux transformation and the explicit solutions of differential—difference and difference—difference evolution equations I,” Lett. Math. Phys., 3, 217–222 (1979).
V. B. Matveev, “Darboux transformation and explicit solutions of the Kadomtsev—Petviashvili equation, depending on functional parameters,” Lett. Math. Phys., 3, 213–216 (1979).
V. Spiridonov and A. Zhedanov, “Discrete Darboux transformations, the discrete-time Toda lattice, and the Askey—Wilson polynomials,” Meth. Appl. Anal., 369–398 (1995).
J. J. C. Nimmo and R. Willox, “Darboux transformations for the two-dimensional Toda system,” Proc. Roy. Soc. London Ser. A, 453, 2497–2525 (1997).
J. J. C. Nimmo, “Darboux transformations and the discrete KP equation,” J. Phys. A: Math. Gen., 30, 8693–9704 (1997).
M. Sato, “Soliton equations as dynamical systems on infinite dimensional Grassmann manifolds,” in: Random Systems and Dynamical Systems (Kyoto, 7–9 January 1981, RIMS Kôkyûroku, Vol. 439), Kyoto Univ., Kyoto (1981), pp. 30–46.
T. Ohta, J. Satsuma, D. Takahashi, and T. Tokihiro, “An elementary introduction to Sato theory,” Prog. Theor. Phys. Suppl., 94, 210–241 (1988).
T. Miwa, M. Jimbo, and E. Date, Solitons: Differential Equations, Symmetries, and Infinite Dimensional Algebras (Cambridge Tracts in Mathematics, Vol. 135), Cambridge Univ. Press, Cambridge (2000).
F. W. Nijhoff, “Lax pair for the Adler (lattice Krichever—Novikov) system,” Phys. Lett. A, 297, 49–58 (2002).
A. I. Bobenko and Yu. B. Suris, “Integrable systems on quad-graphs,” Int. Math. Res. Notices, 2002, 573–611 (2002).
J. Hietarinta, N. Joshi, and F. W. Nijhoff, Discrete Systems and Integrability, Cambridge Univ. Press, Cambridge (2016).
V. E. Adler, A. I. Bobenko, and Yu. B. Suris, “Classification of integrable equations on quad-graphs: The consistency approach,” Commun. Math. Phys., 233, 513–543 (2003).
V. E. Adler, A. I. Bobenko, and Yu. B. Suris, “Discrete nonlinear hyperbolic equations: Classification of integrable cases,” Funct. Anal. Appl., 43, 3–17 (2009).
F. W. Nijhoff, J. Atkinson, and J. Hietarinta, “Soliton solutions for ABS lattice equations: I. Cauchy matrix approach,” J. Phys. A: Math. Theor., 42, 404005 (2009).
J. Hietarinta and D. J. Zhang, “Soliton solutions for ABS lattice equations: II. Casoratians and bilinearization,” J. Phys. A: Math. Theor., 42, 404006 (2009).
E. Schrödinger, “A method of determining quantum-mechanical eigenvalues and eigenfunctions,” Proc. Roy. Irish Acad. Sect. A, 46, 9–16 (1940).
L. Infeld and T. E. Hull, “The factorization method,” Rev. Modern Phys., 23, 21–68 (1951).
F. W. Nijhoff and H. Capel, “The discrete Korteweg—de Vries equation,” Acta Appl. Math., 39, 133–158 (1995).
Q. P. Liu and Y. Q. Wang, “A note on a discrete Schrödinger spectral problem and associated evolution equations,” Acta Math. Sci. Ser. A, 26, 773–777 (2006).
Y. Shi, J. J. C. Nimmo, and D.-J. Zhang, “Darboux and binary Darboux transformations for discrete integrable systems I: Discrete potential KdV equation,” J. Phys. A: Math. Theor., 47, 025205 (2013).
Y. Shi, J. J. C. Nimmo, and J. X. Zhao, “Darboux and binary Darboux transformations for discrete integrable systems. II. Discrete potential mKdV equation,” SIGMA, 13, 036 (2017); arXiv:1705.09896v1 [nlin.SI] (2017).
C.-W. Cao and G.-Y. Zhang, “Lax Pairs for discrete integrable equations via Darboux transformations,” Chinese Phys. Lett., 29, 050202 (2012).
S. Konstantinou-Rizos, “Darboux transformations, discrete integrable systems, and related Yang—Baxter maps,” Doctoral dissertation, University of Leeds, Leeds, UK (2014); arXiv:1410.5013v1 [nlin.SI] (2014).
S. V. Smirnov, “Factorization of Darboux—Laplace transformations for discrete hyperbolic operators,” Theor. Math. Phys., 199, 621–636 (2019).
A. P. Fordy and J. Gibbons, “Factorization of operators: I. Miura transformations,” J. Math. Phys., 21, 2508–2510 (1980).
A. P. Fordy and J. Gibbons, “Factorization of operators II,” J. Math. Phys., 22, 1170–1175 (1981).
M. Boiti, F. Pempinelli, B. Prinari, and A. Spire, “An integrable discretization of KdV at large times,” Inverse Probl., 17, 515–526 (2001).
S. Butler and N. Joshi, “An inverse scattering transform for the lattice potential KdV equation,” Inverse Probl., 26, 115012 (2010).
A. N. Hone, “Exact discretization of the Ermakov—Pinney equation,” Phys. Lett. A, 263, 347–354 (1999).
A. P. Veselov and A. B. Shabat, “Dressing chains and spectral theory of the Schrödinger operator,” Funct. Anal. Appl., 27, 81–96 (1993).
H. D. Wahlquist and F. B. Estabrook, “Bäcklund transformation for solutions of the Korteweg—de Vries equation,” Phys. Rev. Lett., 31, 1386–1390 (1973).
C. A. Evripidou, P. H. van der Kamp, and C. Zhang, “Dressing the dressing chain,” SIGMA, 14, 059 (2018).
R. Hirota, “Nonlinear partial difference equations: III. Discrete sine-Gordon equation,” J. Phys. Soc. Japan, 43, 2079–2086 (1977).
A. Dobrogowska and G. Jakimowicz, “Factorization method applied to the second order difference equations,” Appl. Math. Lett., 74, 161–166 (2017).
S. Odake and R. Sasaki, “Crum’s theorem for ‘discrete’ quantum mechanics,” Progr. Theor. Phys., 122, 1067–1079 (2009).
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This research is supported by the National Natural Science Foundation of China (Grant Nos. 11601312, 11631007, and 11875040), the Shanghai Young Eastern Scholar program (2016–2019), the JSPS (Grant-in-Aid for Scientific Research No. 16KT0024), Waseda University (Special Research Project Nos. 2017K-170, 2019C-179, 2019E-036, and 2019R-081), and the MEXT Top Global University Project.
Prepared from an English manuscript submitted by the authors; for the Russian version, see Teoreticheskaya i Matematicheskaya Fizika, Vol. 202, No. 2, pp. 187–206, February, 2020.
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Zhang, C., Peng, L. & Zhang, Dj. Discrete Crum’s Theorems and Lattice KdV-Type Equations. Theor Math Phys 202, 165–182 (2020). https://doi.org/10.1134/S0040577920020038
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DOI: https://doi.org/10.1134/S0040577920020038