Abstract
The large deviation function has been known for a long time in the literature for the displacement of the rightmost particle in a branching random walk (BRW), or in a branching Brownian motion (BBM). More recently a number of generalizations of the BBM and of the BRW have been considered where selection or coalescence mechanisms tend to limit the exponential growth of the number of particles. Here we try to estimate the large deviation function of the position of the rightmost particle for several such generalizations: the L-BBM, the N-BBM, and the coalescing branching random walk (CBRW) which is closely related to the noisy FKPP equation. Our approach allows us to obtain only upper bounds on these large deviation functions. One noticeable feature of our results is their non analytic dependence on the parameters (such as the coalescence rate in the CBRW).
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Notes
Although the right-hand side of (4.1) is an event of the BBM, not of the L-BBM, we use the superscript in \(\widetilde{E}_t^{\mathrm {LBBM}}\) to remind us that it will serve to study the large deviation function for the L-BBM. A similar remark applies to the forthcoming events \(\widetilde{E}_t^{\mathrm {NBBM}}\) and \(\widetilde{E}_t^{\mathrm {CBRW}}\).
The choice of the power 2 / 3 is arbitrary; anything in \((\frac{1}{2}, \, 1)\) will do the job.
The choice of 3 on the right-hand side is arbitrary; anything in \((2, \, \infty )\) will do the job.
The choice of powers in \((\ln N)^2\) and \((\ln N)^3\) are arbitrary: they can be replaced by \(C_1 \ln N\) and \(C_2 \ln N\) with two sufficiently large constants \(C_1\) and \(C_2\).
As we shall point out in Sect. 5, this picture is probably inaccurate, and is only due to the fact that our upper bound for \(Q(x, \, s)\) is not optimal. We conjecture that regardless of the value of v, the subtrees never make any particular effort in the N-BBM, which would be in complete contrast with the L-BBM.
References
Aïdékon, E.: Convergence in law of the minimum of a branching random walk. Ann. Probab. 41, 1362–1426 (2013)
Bérard, J., Gouéré, J.B.: Brunet–Derrida behavior of branching-selection particle systems on the line. Commun. Math. Phys. 298, 323–342 (2010)
Bérard, J., Maillard, P.: The limiting process of \(N\)-particle branching random walk with polynomial tails. Electron. J. Probab. 19, 1–17 (2014)
Berestycki, J. (2015). Topics on branching Brownian motion. Lecture notes. http://www.stats.ox.ac.uk/berestyc/articles.html
Berestycki, N., Zhao, L. Z., (2013). The shape of multidimensional Brunet–Derrida particle systems. arXiv preprint arXiv:1305.0254
Biggins, J.D.: Large deviations and branching processes. Chernoff’s theorem in the branching random walk. J. Appl. Probab. 14, 630–636 (1977)
Bramson, M.D.: Maximal displacement of branching Brownian motion. Commun. Pure Appl. Math. 31, 531–581 (1978)
Bramson, M.D.: Convergence of Solutions of the Kolmogorov Equation to Travelling Waves, vol. 44, vol. 285. American Mathematical Society, Providence (1983)
Brunet, E., Derrida, B.: Shift in the velocity of a front due to a cutoff. Phys. Rev. E 56, 2597 (1997)
Brunet, E., Derrida, B.: Effect of microscopic noise on front propagation. J. Stat. Phys. 103, 269–282 (2001)
Brunet, E., Derrida, B., Mueller, A.H., Munier, S.: Noisy traveling waves: effect of selection on genealogies. Europhys. Lett. 76, 1 (2006)
Brunet, E., Derrida, B., Mueller, A.H., Munier, S.: Phenomenological theory giving the full statistics of the position of fluctuating pulled fronts. Phys. Rev. E 73, 056126 (2006)
Brunet, E., Derrida, B., Mueller, A.H., Munier, S.: Effect of selection on ancestry: an exactly soluble case and its phenomenological generalization. Phys. Rev. E 76, 041104 (2007)
Chauvin, B., Rouault, A.: KPP equation and supercritical branching Brownian motion in the subcritical speed area. Application to spatial trees. Probab. Theory Relat. Fields 80, 299–314 (1988)
Chen, X. (2013). Scaling limit of the path leading to the leftmost particle in a branching random walk. arXiv preprint arXiv:1305.6723
Conlon, J.G., Doering, C.R.: On travelling waves for the stochastic Fisher–Kolmogorov–Petrovsky–Piscunov equation. J. Stat. Phys. 120, 421–477 (2005)
Dembo, A., Zeitouni, O.: Large Deviations Techniques and Applications. Springer Science & Business Media, Berlin (2009)
Den Hollander, F.: Large Deviations. American Mathematical Society, Providence (2008)
Doering, C.R., Mueller, C., Smereka, P.: Interacting particles, the stochastic Fisher–Kolmogorov–Petrovsky–Piscounov equation, and duality. Phys. A 325, 243–259 (2003)
Durrett, R., Remenik, D.: Brunet–Derrida particle systems, free boundary problems and Wiener–Hopf equations. Ann. Probab. 39, 2043–2078 (2011)
McKean, H.P.: Application of brownian motion to the equation of Kolmogorov–Petrovskii–Piskunov. Commun. Pure Appl. Math. 28, 323–331 (1975)
Maillard, P. (2013). Speed and fluctuations of \(N\)-particle branching Brownian motion with spatial selection. arXiv preprint arXiv:1304.0562
Mallein, B. (2015). Branching random walk with selection at critical rate. arXiv preprint arXiv:1502.07390
Meerson, B., Sasorov, P.V.: Negative velocity fluctuations of pulled reaction fronts. Phys. Rev. E 84, 030101 (2011)
Meerson, B., Vilenkin, A., Sasorov, P.V.: Emergence of fluctuating traveling front solutions in macroscopic theory of noisy invasion fronts. Phys. Rev. E 87, 012117 (2013)
Mueller, C., Mytnik, L., Quastel, J.: Effect of noise on front propagation in reaction-diffusion equations of KPP type. Invent. Math. 184, 405–453 (2011)
Mueller, C., Sowers, R.B.: Random travelling waves for the KPP equation with noise. J. Funct. Anal. 128, 439–498 (1995)
Pain, M. (2015). Velocity of the \(L\)-branching Brownian motion. arXiv preprint arXiv:1510.02683
Panja, D.: Effects of fluctuations on propagating fronts. Phys. Rep. 393, 87–174 (2004)
Pechenik, L., Levine, H.: Interfacial velocity corrections due to multiplicative noise. Phys. Rev. E 59, 3893 (1999)
Ramola, K., Majumdar, S.N., Schehr, G.: Spatial extent of branching Brownian motion. Phys. Rev. E 91, 042131 (2015)
Rouault, A. (2000). Large deviations and branching processes. In Proceedings of the 9th International Summer School on Probability Theory and Mathematical Statistics (Sozopol, 1997). Pliska Studia Mathematica Bulgarica 13, pp. 15–38
Shi, Z., (2015). Branching random walks. École d’été Saint-Flour XLII. Lecture Notes in Mathematics 2151. Springer, Berlin (2012)
van Saarloos, W.: Front propagation into unstable states. Phys. Rep. 386(2), 29–222 (2003)
Zeitouni, O. (2012). Branching random walks and Gaussian fields. Lecture notes. http://www.wisdom.weizmann.ac.il/zeitouni/pdf/notesBRW
Acknowledgments
B.D. thanks the LPMA in Jussieu for its hospitality during the whole academic year 2014–2015.
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Derrida, B., Shi, Z. Large Deviations for the Branching Brownian Motion in Presence of Selection or Coalescence. J Stat Phys 163, 1285–1311 (2016). https://doi.org/10.1007/s10955-016-1522-z
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DOI: https://doi.org/10.1007/s10955-016-1522-z