Abstract
In classes of N-particle systems and lattice models, the speed of front propagation is approximated by that of the corresponding continuum model, and for many such systems, the rate of convergence to the continuum speed is known to be slow as N → ∞. This slow convergence has been captured by including a cutoff function on the reaction terms in the continuum models. For example, the Fisher–Kolmogorov–Petrowskii–Piscounov (FKPP) equation with a cutoff has fronts that travel at the speed \({c \sim c_{\rm FKPP} - \frac{\pi^2}{(\ln(N))^2}}\) , which agrees well with data from numerical simulations of the corresponding N-particle systems, where c FKPP is the linear spreading speed. In Panja and van Saarloos (Phys Rev E 66:015206, 2002), an example is presented in which a small enhancement of the reaction function causes the propagation speeds of fronts to be larger than c FKPP. Such front speeds are also observed in stochastic lattice models where the growth rates in the regime of few particles are modified. In this article, we analyze the dynamics of traveling fronts in the FKPP equation with the constant enhancement function employed by Panja and van Saarloos. We present formulas for the wave speeds, develop the criteria on the parameters for which the front speeds are larger than the linear spreading speed even in the limit in which the size of the cutoff domain vanishes, study the rate of approach as N → ∞, and identify the mechanisms in phase space by which the constant enhancement of the reaction function makes possible the larger than linear wave speeds. In addition, we extend these results to the FKPP equation with two other enhancement functions, which are also of interest for continuum level modeling of lattice models and many-particle systems in the regimes of small numbers of particles, namely a linear enhancement function and an enhancement that is uniform above the linearized reaction function. We also derive explicit formulas for the parameters in these problems. The mathematical techniques used herein are geometric singular perturbation theory, geometric desingularization, invariant manifold theory, and normal form theory, all from dynamical systems.
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Abramowitz, M., Stegun, I.A. (Eds.): Handbook of Mathematical Functions with Formulas, Graphs, and Mathematical Tables, National Bureau of Standards, Applied Mathematics Series 55. Dover Publications, New York (1972)
Allen S.M., Cahn J.W.: A macroscopic theory for antiphase boundary motion and its application to antiphase domain coarsening. Acta Metal. Mater. 27, 1085–1095 (1979)
Aronson, D.G., Weinberger, H.F.: Nonlinear diffusion in population genetics, combustion, and nerve pulse propagation. In: Partial Differential Equations and Related Topics, Lecture Notes in Mathematics, vol. 446, pp. 5–49. Springer, Berlin (1975)
Aronson D.G., Weinberger H.F.: Multidimensional nonlinear diffusion arising in population genetics. Adv. Math. 30, 33–76 (1978)
Benguria R.D., Depassier M.C.: Speed of pulled fronts with cutoff. Phys. Rev. E 75, 051106 (2007)
Benguria R.D., Depassier M.C., Haikala V.: Effect of a cutoff on pushed and bistable fronts of the reaction–diffusion equation. Phys. Rev. E 76, 051101 (2007)
Bonckaert P.: Partially hyperbolic fixed points with constraints. Trans. Am. Math. Soc. 348, 997–1011 (1996)
Bramson M., Calderoni P., DeMasi A., Ferrari P., Lebowitz J., Schonmann R.H.: Microscopic selection principle for a reaction–diffusion equation. J. Stat. Phys. 45, 905–920 (1986)
Breuer H.P., Huber W., Petruccione F.: Fluctuation effects on wave propagation in a reaction–diffusion process. Phys. D 73, 259–273 (1994)
Breuer H.P., Huber W., Petruccione F.: The Macroscopic limit in a stochastic reaction–diffusion process. Europhys. Lett. 30, 69 (1995)
Britton N.F.: Reaction–Diffusion Equations and Their Applications to Biology. Academic Press Inc., London (1986)
Brunet E., Derrida B.: Shift in the velocity of a front due to a cutoff. Phys. Rev. E 56(3), 2597–2604 (1997)
Chow S.-N., Li C., Wang D.: Normal Forms and Bifurcation of Planar Vector Fields. Cambridge University Press, Cambridge (1994)
Cook J., Derrida B.: Lyapunov exponents of large, sparse random matrices and the problem of directed polymers with complex random weights. J. Stat. Phys. 61, 961–986 (1990)
Derrida B., Spohn H.: Polymers on disordered trees, spin glasses, and traveling waves. J. Stat. Phys. 51, 817–840 (1988)
Dumortier, F.: Techniques in the theory of local bifurcations: blow-up, normal forms, nilpotent bifurcations, singular perturbations. In: Schlomiuk, D. (ed.), Bifurcations and Periodic Orbits of Vector Fields, NATO ASI Series C, vol. 408, pp. 19–73, Kluwer Acad. Publ., Dordrecht (1993)
Dumortier F.: Sharp upperbounds for the number of large amplitude limit cycles in polynomial Lienard systems. Discrete Contin. Dyn. Syst. 32, 1465–1479 (2012)
Dumortier, F., De Maesschalck, P.: Topics in singularities and bifurcations of vector fields. In: Ilyashenko, Y., Rousseau, C., Sabidussi, G. (eds.) Normal Forms, Bifurcations, and Finiteness Problems in Differential Equations, NATO Sci. Ser. II Math. Phys. Chem., vol. 137, pp. 33–86. Kluwer Acad. Publ., Dordrecht (2004)
Dumortier F., Kaper T.J.: Wave speeds for pushed fronts in scalar reaction–diffusion equations with cut-off. RIMS Kokyuroku Bessatsu B31, 117–134 (2012)
Dumortier F., Popović N., Kaper T.J.: The asymptotic critical wave speed in a family of scalar reaction–diffusion equations. J. Math. Anal. Appl. 326, 1007–1023 (2007)
Dumortier F., Popović N., Kaper T.J.: The critical wave speed for the FKPP equation with cut-off. Nonlinearity 20, 855–877 (2007)
Dumortier F., Popović N., Kaper T.J.: A geometric approach to bistable front propagation in scalar reaction–diffusion equations with cut-off. Phys. D 239, 1984–1999 (2010)
Dumortier F., Roussarie R.: Canard cycles and center manifolds. Mem. A.M.S. 121(577), 1–100 (1996)
Dumortier, F., Roussarie, R.: Geometric singular perturbation theory beyond normal hyperbolicity. In: Jones, C.K.R.T., Khibnik, A. (eds.) Multiple-Time-Scale Dynamical Systems, IMA Vol. Math. Appl., vol. 122, pp. 29–63. Springer, New York (2001)
Dumortier F., Roussarie R., Sotomayor J.: Bifurcations of cuspidal loops. Nonlinearity 10, 1369–1408 (1997)
Fisher R.A.: The wave of advance of advantageous genes. Ann. Eugenics 7, 355–369 (1937)
Guckenheimer J., Holmes P.: Nonlinear Oscillations, Dynamical Systems, and Bifurcations of Vector Fields, Applied Mathematics Sciences Series, vol. 42. Springer, New York (1983)
Keener J., Sneyd J.: Mathematical Physiology, Interdisciplinary Applied Mathematics vol. 8. Springer, New York (1998)
Kerstein A.R.: Computational study of propagating fronts in a lattice-gas model. J. Stat. Phys. 45, 921–931 (1986)
Kessler D.A., Ner Z., Sander L.M.: Front propagation: precursors, cutoffs, and structural stability. Phys. Rev. E 58(1), 107–114 (1998)
Kolmogorov A.N., Petrowskii I.G., Piscounov N.: Etude de l’équation de la diffusion avec croissance de la quantité de matiére et son application à un problème biologique. Moscow Univ. Math. Bull. 1, 1–25 (1937)
Krupa M., Szmolyan P.: Extending geometric singular perturbation theory to nonhyperbolic points–fold and canard points in two dimensions. SIAM J. Math. Anal. 33, 286–314 (2001)
Krupa M., Szmolyan P.: Relaxation oscillation and canard explosion. J. Differ. Equ. 174, 312–368 (2001)
Mai J., Sokolov I.M., Blumen A.: Front propagation in one-dimensional autocatalytic reactions: The breakdown of the classical picture at small particle concentrations. Phys. Rev. E 62, 141–145 (2000)
Méndez V., Campos D., Zemskov E.P.: Variational principles and the shift in the front speed due to a cutoff. Phys. Rev. E 72(5), 056113 (2005)
Panja D., van Saarloos W.: Fronts with a growth cut-off but with speed higher than the linear spreading speed. Phys. Rev. E, 66, 015206 (2002)
Popović, N.: Front speeds, cut-offs, and desingularization: a brief case study in fluids and waves, Contemp. Math., vol. 440, pp. 187–195. Amer. Math. Soc., Providence, RI (2007)
Popović N.: A geometric analysis of front propagation in a family of degenerate reaction–diffusion equations with cut-off. Z. Angew. Math. Phys. 62, 405–437 (2011)
Popović N.: A geometric analysis of front propagation in an integrable Nagumo equation with a linear cut-off. Phys. D 241, 1976–1984 (2012)
Popović N., Szmolyan P.: A geometric analysis of the Lagerstrom model problem. J. Differ. Equ. 199, 290–325 (2004)
Sternberg S.: On the structure of local homeomorphisms of Euclidean n-space II. Am. J. Math. 80, 623–631 (1958)
van Saarloos W.: Front propagation into unstable states. Phys. Rep. 386, 29–222 (2003)
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Dumortier, F., Kaper, T.J. Wave speeds for the FKPP equation with enhancements of the reaction function. Z. Angew. Math. Phys. 66, 607–629 (2015). https://doi.org/10.1007/s00033-014-0422-9
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DOI: https://doi.org/10.1007/s00033-014-0422-9