Eur. Phys. J. D (2013) 67: 172
https://doi.org/10.1140/epjd/e2013-40170-x

Regular Article

Effect of complex inter-site couplings on the excitation energy transfer in the FMO complex

¹ School of Physics and Optoelectronic Technology, Dalian University of Technology , Dalian 116024, P.R. China
² Centre for Quantum Technologies and Department of Physics, National University of Singapore, 117543 Singapore, Singapore

^a e-mail: yixx@dlut.edu.cn

Received: 26 March 2013
Received in final form: 28 April 2013
Published online: 6 August 2013

Abstract

It is believed that the quantum coherence itself cannot explain the very high excitation energy transfer (EET) efficiency in the Fenna-Matthews-Olson (FMO) complex. In this paper, we show that this is not the case if the inter-site couplings take complex values. By phenomenologically introducing phases into the inter-site couplings, we obtain a EET efficiency as high as 0.8972 in contrast to 0.6781 with real inter-site couplings. Dependence of the EET efficiency on the initial states is elaborated. Effects of fluctuations in the site energies and inter-site couplings are also examined.