6 citations · 6 across the 6 of their papers we have counts for
7 papers
Exponential perturbative expansions and coordinate transformations
Ana Arnal, Fernando Casas, Cristina Chiralt
We propose a unified approach for different exponential perturbation techniques used in the treatment of time-dependent quantum mechanical problems, namely the Magnus expansion, th…
A unifying framework for perturbative exponential factorizations
Ana Arnal, Fernando Casas, Cristina Chiralt
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…
Magnus integrators for linear and quasilinear delay differential equations
Ana Arnal, Fernando Casas, Cristina Chiralt
A procedure to numerically integrate non-autonomous linear delay differential equations is presented. It is based on the use of an spectral discretization of the delayed part to tr…
A note on the Baker--Campbell--Hausdorff series in terms of right-nested commutators
Ana Arnal, Fernando Casas, Cristina Chiralt
We get compact expressions for the Baker--Campbell--Hausdorff series $Z = \log(\e^X \, \e^Y)$ in terms of right-nested commutators. The reduction in the number of terms originates…
On the structure and convergence of the symmetric Zassenhaus formula
Ana Arnal, Fernando Casas, Cristina Chiralt
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 expa…
A general formula for the Magnus expansion in terms of iterated integrals of right-nested commutators
Ana Arnal, Fernando Casas, Cristina Chiralt
We present a general expression for any term of the Magnus series as an iterated integral of a linear combination of independent right-nested commutators with given coefficients. T…
A note on trigonometric identities involving non-commuting matrices
Ana Arnal, Fernando Casas, Cristina Chiralt
An algorithm is presented for generating successive approximations to trigonometric functions of sums of non-commuting matrices. The resulting expressions involve nested commutator…