Listar MAT_Articles por autoría "8d02ff65-d98e-4877-8e68-923b379d6bd2"

Mostrando ítems 1-9 de 9

    • openAccess   A Lie-Deprit perturbation algorithm for linear differential equations with periodic coefficients 

      Casas, Fernando; Chiralt, Cristina American Institute of Mathematical Sciences (AIMS) (2014-03)
      A perturbative procedure based on the Lie-Deprit algorithm of classical mechanics is proposed to compute analytic approximations to the fundamental matrix of linear di erential equations with periodic coe cients. These ...

    • openAccess   A note on the Baker–Campbell–Hausdorff series in terms of right-nested commutators 

      Arnal, A.; Casas, Fernando; Chiralt, Cristina Springer (2021-01-27)
      We get compact expressions for the Baker–Campbell–Hausdorff series Z = log(eX eY ) in terms of right-nested commutators. The reduction in the number of terms originates from two facts: (i) we use as a starting point an ...

    • openAccess   A note on trigonometric identities involving non-commuting matrices 

      Arnal, A.; Casas, Fernando; Chiralt, Cristina Springer Milan (2017)
      An algorithm is presented for generating successive approximations to trigonometric functions of sums of non-commuting matrices. The resulting expressions involve nested commutators of the respective matrices. The procedure ...

    • openAccess   A Unifying Framework for Perturbative Exponential Factorizations 

      Arnal, A.; Casas, Fernando; Chiralt, Cristina; Oteo, José-Angel MDPI (2021-03-17)
      We propose a framework where Fer and Wilcox expansions for the solution of differential equations are derived from two particular choices for the initial transformation that seeds the product expansion. In this scheme, ...

    • openAccess   Bifurcations in the two imaginary centers problem 

      Chiralt, Cristina; Campos, Beatriz; Vindel, Pura Institute of Mathematics of the Academy of Sciences of the Czech Republic (2011)
      In this paper we show that, for a given value of the energy, there is a bifurcation for the two imaginary centers problem. For this value not only the configuration of the orbits changes but also a change in the topology ...

    • openAccess   Exponential Perturbative Expansions and Coordinate Transformations 

      Arnal, A.; Casas, Fernando; Chiralt, Cristina MDPI (2020)
      We propose a unified approach for different exponential perturbation techniques used in the treatment of time-dependent quantum mechanical problems, namely the Magnus expansion, the Floquet–Magnus expansion for periodic ...

    • openAccess   Magnus integrators for linear and quasilinear delay differential equations 

      Arnal, A.; Casas, Fernando; Chiralt, Cristina Elsevier (2023-04-29)
      A procedure to numerically integrate non-autonomous linear delay differential equations is presented. It is based on the use of a spectral discretization of the delayed part to transform the original problem into a matrix ...

    • closedAccess   On the structure and convergence of the symmetric Zassenhaus formula 

      Arnal, A.; Casas, Fernando; Chiralt, Cristina Elsevier (2017-08)
      We propose and analyze a symmetric version of the Zassenhaus formula for disentangling the exponential of two non-commuting operators. A recursive procedure for generating the expansion up to any order is presented which ...

    • openAccess   Quantitative analysis of competition models 

      Chiralt, Cristina; Ferragut, Antoni; Gasull, Armengol; Vindel, Pura Elsevier (2017)
      We study a 2-species Lotka–Volterra type differential system, modeling competition between two species and having a coexistence equilibrium in the first quadrant. In case that this equilibrium is of saddle type, its ...