|  Chaos | 
In General > s.a. complexity;  physics
  paradigms; Predictability; quantum chaos;
  randomness; thermodynamics.
  * Idea: Chaos is the study
    of (non-linear) dynamical systems with unstable behavior; Deterministic,
    but unpredictable and irregular for almost all initial conditions and almost
    all variations thereof – a small variation results in a totally different
    trajectory; The mechanism by which this happens is that the paths locally diverge
    exponentially, then fold back and mix; The motion resembles a random process,
    because its description requires a maximally long sequence of symbols.
  * History: First observed by
    Hadamard in 1898 for geodesic flow in a constant negative curvature manifold;
    The consequences were understood by Duhem [@1906] and Poincaré [@1908];
    It has now become the second holistic XX century innovation (the first one was
    quantum mechanics), questioning our mechanistic view.
  * Remark: Many non-chaotic systems
    exhibit sensitive dependence on initial conditions, but only for unstable fixed
    points or unstable periodic orbits; Also, "chaos" sometimes stands for
    Boltzmann's molecular disorder (> see statistical mechanics).
  * Characteristics:
    Universality, low-dimensionality, period doubling.
  * Description: For few
    degrees of freedom, the transition from order to chaos is well described
    and understood, theoretically and experimentally; Separatrices are
    seeds of chaos when disturbances are added; Full turbulent behavior is
    not understood, but described phenomenologically in terms of fractals
    and strange attractors (dissipative systems).
  @ I: Gleick 87;
    Von Baeyer ThSc(91)jul;
    Gutzwiller SA(92)jan [quantum];
    Ruelle 92;
    Kellert 93 [conceptual];
    Lorenz 93;
    Smith 07
      [r JPA(07)].
  @ II: Kadanoff PT(83)dec;
    Zabusky PT(84)jul;
    Chernikov et al PT(88)nov;
    Ornstein Sci(89)jan;
    Stewart NS(89)nov;
    Gaponov-Grekhov & Rabinovich PT(90)jul;
    PW(90)apr; NS(90)sep29, p49-52,
    NS(90)oct10; Hall 92;
    Tél & Gruiz 06;
    Kautz 10;
    Gulick 12;
    Letellier 13;
    Stetz 16 [including numerical];
    Goodson 16 [mathematical].
  @ Historical: Sinai JSP(10) [overview];
    Shepelyansky PT(14)-a1306 [Chirikov's 1959 pioneering results];
    Motter & Campbell PT(13)may [chaos at 50].
  @ And randomness: Svozil PLA(89);
    Winnie PhSc(92)jun;
    Amigó et al PLA(06) [non-statistical test];
    Caprara & Vulpiani in(16)-a1605 [and stochastic models].
  @ Related topics: Iooss et al ed-83 [lectures];
    Sprott PLA(93) [genericity];
    Crisanti et al JPA(94) [changing parameters];
    Antoniou & Suchanecki FP(94) [and logic];
    Koperski BJPS(01) [conceptual];
    Yahalom et al IJGMP-a1112 [necessary conditions];
    Li a1305 [some open problems];
    > s.a. Fermat's Last Theorem.
  > Online resources:
    see The Chaos Hypertextbook.
Control
  * Stochastic resonance:
    The amplification and optimization of feeble input with the assistance of noise.
  @ References: Ditto & Pecora SA(93)aug;
    Peak & Frame 94;
    Ott & Spano PT(95)may;
    Gammaitoni et al RMP(98) [stochastic resonance];
    Boccaletti et al PRP(00),
    PRP(02) [synchronization];
    Bowong & Kakmeni PS(03)
      [stability and suration of synchronization];
    Chacón 05 [of homoclinic chaos];
    Gauthier AJP(03)aug [RL];
    Vargas et al AJP(09)sep [bouncing ball].
Obtaining Information / Analysis of Chaotic Data
  * Experimentally: Fluctuations
    in the evolution of the system are not always easy to distinguish from noise.
  * Criteria: They include the
    measurement of the correlation dimension.
  @ Data analysis: news Nat(90)oct;
    Ruelle PRS(90),
    PT(94)jul [criteria and criticism];
    Abarbanel et al RMP(93);
    Ott et al 94;
    Olbrich & Kantz PLA(97),
    Xiaofeng  & Lai JPA(00) [time series];
    Abarbanel 97.
  @ Related topics:
    Steeb et al JPA(94) [maximum entropy formalism];
    in Kaplan & Glass 95 [phase space reconstruction, II];
    Buchler cd/97-conf [global flow reconstruction method].
Other Effects and Topics > s.a. chaotic systems;
  mathematical description; statistical mechanics.
  * Routes to chaos: The
    three universal routes to chaos displayed by the prototypical logistic
    and circle maps are period doubling, intermittency, and quasiperiodicity
    routes; In these situations the dynamical behavior is exactly describable
    through infinite families of Tsallis' q-exponential functions.
  * Universality: Behavior that
    is quantitatively identical for a broad class of systems; The first and
    most famous example is the period-doubling route to chaos.
  @ Period doubling: Feigenbaum JSP(78),
    JSP(79);
    Coppersmith AJP(99)jan [Feigenbaum's renormalization group equation].
  @ And transport: Zaslavsky PRP(02) [anomalous];
    Vollmer PRP(02) [and non-equilibrium thermodynamics].
  @ Related topics: Kandrup et al MNRAS(00)ap/99 [low-amplitude noise in Hamiltonian systems];
    Firpo & Ruffo JPA(01) [suppression in large-size limit];
    Zheng et al IJTP(03) [observer dependence];
    Baldovin PhyA(06) [incipient chaos, routes, and glass formation];
    Nakagawa et al JHEP(18)-a1805 [and relative entropy];
    Xu et al PRL(20)-a1912 [scrambling does not imply chaos].
  > And fundamental physics:
    see information; QED; topological field theories.
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  send feedback and suggestions to bombelli at olemiss.edu – modified 10 apr 2020