A density matrix approach to the dynamical properties of a two-site Holstein model
Dipartimento di Fisica, Università dell'Aquila, via Vetoio, 67100 L'Aquila, Italy
2 CRS SMC, INFM-CNR, 00100 Roma, Italy
The two-site Holstein model represents a first non-trivial paradigm for the interaction between an itinerant charge with a quantum oscillator, a very common topic in different ambits. Exact results can be achieved both analytically and numerically, nevertheless it can be useful to compare them with approximate, semi-classical techniques in order to highlight the role of quantum effects. In this paper we consider the adiabatic limit in which the oscillator is slower than the electron. A density matrix approach is introduced for studying the charge dynamics and the exact results are compared with two different approximations: a Born-Oppenheimer-based Static Approximation for the oscillator (SA) and a Quantum-classical (QC) dynamics.
© EDP Sciences, Springer-Verlag, 2008