A New Variational Study for Two-Site Holstein Model |
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Authors: | REN Qing-Bao CHEN Qing-Hu |
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Institution: | 1. Department of Physics, Lishui College, Lishui 323000, China
;2. Department of Physics, Zhejiang University, Hangzhou 310027, China |
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Abstract: | A variational approach is developed to study the groundstate (GS) of the
two-site Holstein model. By the extended coherent state, where the more
phonon correlations are easily incorporated, we can get the very accurate ground state energy for all electron-phonon coupling range in typical values of hopping integral t=0.5,1.1, and 2.1 (in units of phonon frequency ω0), which covers the crossover region from
antiadiabatic limit to the adiabatic limit. Within a very wide t
range 0,2.7], the exact results for the GS energy are obtained
with the twelfth (fourteenth) order corrections to the zeroth order wave
function. Moreover, the present approach is more concise than any
other analytical ones in this field, and hopefully can be easily
generalized to many other Holstein models. |
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Keywords: | polaron coherent state Holstein model |
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