TY - JOUR AB - We consider billiards obtained by removing from the plane finitely many strictly convex analytic obstacles satisfying the non-eclipse condition. The restriction of the dynamics to the set of non-escaping orbits is conjugated to a subshift, which provides a natural labeling of periodic orbits. We show that under suitable symmetry and genericity assumptions, the Marked Length Spectrum determines the geometry of the billiard table. AU - De Simoi, Jacopo AU - Kaloshin, Vadim AU - Leguil, Martin ID - 12877 JF - Inventiones Mathematicae SN - 0020-9910 TI - Marked Length Spectral determination of analytic chaotic billiards with axial symmetries VL - 233 ER - TY - JOUR AB - In the paper, we establish Squash Rigidity Theorem—the dynamical spectral rigidity for piecewise analytic Bunimovich squash-type stadia whose convex arcs are homothetic. We also establish Stadium Rigidity Theorem—the dynamical spectral rigidity for piecewise analytic Bunimovich stadia whose flat boundaries are a priori fixed. In addition, for smooth Bunimovich squash-type stadia we compute the Lyapunov exponents along the maximal period two orbit, as well as the value of the Peierls’ Barrier function from the maximal marked length spectrum associated to the rotation number 2n/4n+1. AU - Chen, Jianyu AU - Kaloshin, Vadim AU - Zhang, Hong Kun ID - 14427 JF - Communications in Mathematical Physics SN - 0010-3616 TI - Length spectrum rigidity for piecewise analytic Bunimovich billiards ER - TY - JOUR AB - In holomorphic dynamics, complex box mappings arise as first return maps to wellchosen domains. They are a generalization of polynomial-like mapping, where the domain of the return map can have infinitely many components. They turned out to be extremely useful in tackling diverse problems. The purpose of this paper is: • To illustrate some pathologies that can occur when a complex box mapping is not induced by a globally defined map and when its domain has infinitely many components, and to give conditions to avoid these issues. • To show that once one has a box mapping for a rational map, these conditions can be assumed to hold in a very natural setting. Thus, we call such complex box mappings dynamically natural. Having such box mappings is the first step in tackling many problems in one-dimensional dynamics. • Many results in holomorphic dynamics rely on an interplay between combinatorial and analytic techniques. In this setting, some of these tools are: • the Enhanced Nest (a nest of puzzle pieces around critical points) from Kozlovski, Shen, van Strien (AnnMath 165:749–841, 2007), referred to below as KSS; • the Covering Lemma (which controls the moduli of pullbacks of annuli) from Kahn and Lyubich (Ann Math 169(2):561–593, 2009); • the QC-Criterion and the Spreading Principle from KSS. The purpose of this paper is to make these tools more accessible so that they can be used as a ‘black box’, so one does not have to redo the proofs in new settings. • To give an intuitive, but also rather detailed, outline of the proof from KSS and Kozlovski and van Strien (Proc Lond Math Soc (3) 99:275–296, 2009) of the following results for non-renormalizable dynamically natural complex box mappings: • puzzle pieces shrink to points, • (under some assumptions) topologically conjugate non-renormalizable polynomials and box mappings are quasiconformally conjugate. • We prove the fundamental ergodic properties for dynamically natural box mappings. This leads to some necessary conditions for when such a box mapping supports a measurable invariant line field on its filled Julia set. These mappings are the analogues of Lattès maps in this setting. • We prove a version of Mañé’s Theorem for complex box mappings concerning expansion along orbits of points that avoid a neighborhood of the set of critical points. AU - Clark, Trevor AU - Drach, Kostiantyn AU - Kozlovski, Oleg AU - Strien, Sebastian Van ID - 11553 IS - 2 JF - Arnold Mathematical Journal SN - 2199-6792 TI - The dynamics of complex box mappings VL - 8 ER - TY - JOUR AB - This is a collection of problems composed by some participants of the workshop “Differential Geometry, Billiards, and Geometric Optics” that took place at CIRM on October 4–8, 2021. AU - Bialy, Misha AU - Fiorebe, Corentin AU - Glutsyuk, Alexey AU - Levi, Mark AU - Plakhov, Alexander AU - Tabachnikov, Serge ID - 10706 JF - Arnold Mathematical Journal SN - 2199-6792 TI - Open problems on billiards and geometric optics VL - 8 ER - TY - JOUR AB - We study rigidity of rational maps that come from Newton's root finding method for polynomials of arbitrary degrees. We establish dynamical rigidity of these maps: each point in the Julia set of a Newton map is either rigid (i.e. its orbit can be distinguished in combinatorial terms from all other orbits), or the orbit of this point eventually lands in the filled-in Julia set of a polynomial-like restriction of the original map. As a corollary, we show that the Julia sets of Newton maps in many non-trivial cases are locally connected; in particular, every cubic Newton map without Siegel points has locally connected Julia set. In the parameter space of Newton maps of arbitrary degree we obtain the following rigidity result: any two combinatorially equivalent Newton maps are quasiconformally conjugate in a neighborhood of their Julia sets provided that they either non-renormalizable, or they are both renormalizable “in the same way”. Our main tool is a generalized renormalization concept called “complex box mappings” for which we extend a dynamical rigidity result by Kozlovski and van Strien so as to include irrationally indifferent and renormalizable situations. AU - Drach, Kostiantyn AU - Schleicher, Dierk ID - 11717 IS - Part A JF - Advances in Mathematics KW - General Mathematics SN - 0001-8708 TI - Rigidity of Newton dynamics VL - 408 ER - TY - JOUR AB - In the class of strictly convex smooth boundaries each of which has no strip around its boundary foliated by invariant curves, we prove that the Taylor coefficients of the “normalized” Mather’s β-function are invariant under C∞-conjugacies. In contrast, we prove that any two elliptic billiard maps are C0-conjugate near their respective boundaries, and C∞-conjugate, near the boundary and away from a line passing through the center of the underlying ellipse. We also prove that, if the billiard maps corresponding to two ellipses are topologically conjugate, then the two ellipses are similar. AU - Koudjinan, Edmond AU - Kaloshin, Vadim ID - 12145 IS - 6 JF - Regular and Chaotic Dynamics KW - Mechanical Engineering KW - Applied Mathematics KW - Mathematical Physics KW - Modeling and Simulation KW - Statistical and Nonlinear Physics KW - Mathematics (miscellaneous) SN - 1560-3547 TI - On some invariants of Birkhoff billiards under conjugacy VL - 27 ER - TY - GEN AB - For any given positive integer l, we prove that every plane deformation of a circlewhich preserves the 1/2and 1/ (2l + 1) -rational caustics is trivial i.e. the deformationconsists only of similarities (rescalings and isometries). AU - Kaloshin, Vadim AU - Koudjinan, Edmond ID - 9435 TI - Non co-preservation of the 1/2 and 1/(2l+1)-rational caustics along deformations of circles ER - TY - JOUR AB - This paper continues the discussion started in [CK19] concerning Arnold's legacy on classical KAM theory and (some of) its modern developments. We prove a detailed and explicit `global' Arnold's KAM Theorem, which yields, in particular, the Whitney conjugacy of a non{degenerate, real{analytic, nearly-integrable Hamiltonian system to an integrable system on a closed, nowhere dense, positive measure subset of the phase space. Detailed measure estimates on the Kolmogorov's set are provided in the case the phase space is: (A) a uniform neighbourhood of an arbitrary (bounded) set times the d-torus and (B) a domain with C2 boundary times the d-torus. All constants are explicitly given. AU - Chierchia, Luigi AU - Koudjinan, Edmond ID - 8689 IS - 1 JF - Regular and Chaotic Dynamics KW - Nearly{integrable Hamiltonian systems KW - perturbation theory KW - KAM Theory KW - Arnold's scheme KW - Kolmogorov's set KW - primary invariant tori KW - Lagrangian tori KW - measure estimates KW - small divisors KW - integrability on nowhere dense sets KW - Diophantine frequencies. SN - 1560-3547 TI - V.I. Arnold's ''Global'' KAM theorem and geometric measure estimates VL - 26 ER -