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Optimal Dephasing for Ballistic Energy Transfer in Disordered Linear Chains
We study the interplay between dephasing, disorder, and openness on transport
efficiency in a one-dimensional chain of finite length , and in particular
the beneficial or detrimental effect of dephasing on transport. The excitation
moves along the chain by coherent nearest-neighbor hopping , under the
action of static disorder and dephasing . The system is open due to
the coupling of the last site with an external acceptor system (sink), where
the excitation can be trapped with a rate , which determines
the opening strength. While it is known that dephasing can help transport in
the localized regime, here we show that dephasing can enhance energy transfer
even in the ballistic regime. Specifically, in the localized regime we recover
previous results, where the optimal dephasing is independent of the chain
length and proportional to or . In the ballistic regime, the
optimal dephasing decreases as or respectively for weak and
moderate static disorder. When focusing on the excitation starting at the
beginning of the chain, dephasing can help excitation transfer only above a
critical value of disorder , which strongly depends on the opening
strength . Analytic solutions are obtained for short chains.Comment: 16 pages, inlcuding 9 figure
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