We show that linearization methods, commonly used to approximate the evolution of the density operator in mixed quantum-classical systems, can be justified when a small parameter, the ratio of masses of the quantum subsystem and bath, is introduced. The same parameter enters in the derivation of the quantum-classical Liouville equation. Although its original derivation followed from a different formalism, here we show that the basis-free form of the quantum-classical Liouville equation for the density operator can also be obtained by linearization of the exact time evolution of this operator. These results show the equivalence among various quantum-classical schemes. (C) 2009 Elsevier B.V. All rights reserved.
Linearization approximations and Liouville quantum-classical dynamics / Bonella, Sara; Ciccotti, Giovanni; Raymond, Kapral. - In: CHEMICAL PHYSICS LETTERS. - ISSN 0009-2614. - 484:4-6(2010), pp. 399-404. [10.1016/j.cplett.2009.11.056]
Linearization approximations and Liouville quantum-classical dynamics
BONELLA, SARA;CICCOTTI, Giovanni;
2010
Abstract
We show that linearization methods, commonly used to approximate the evolution of the density operator in mixed quantum-classical systems, can be justified when a small parameter, the ratio of masses of the quantum subsystem and bath, is introduced. The same parameter enters in the derivation of the quantum-classical Liouville equation. Although its original derivation followed from a different formalism, here we show that the basis-free form of the quantum-classical Liouville equation for the density operator can also be obtained by linearization of the exact time evolution of this operator. These results show the equivalence among various quantum-classical schemes. (C) 2009 Elsevier B.V. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.