Browsing Institut Universitari de Matemàtiques i Aplicacions de Castelló (IMAC) by Author "8d02ff65-d98e-4877-8e68-923b379d6bd2"
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A general formula for the Magnus expansion in terms of iterated integrals of right-nested commutators
Arnal, A.; Casas, Fernando; Chiralt, Cristina IOP (2018-03)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. The relation with the Malvenuto–Reutenauer ... -
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 ... -
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, ... -
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 ...