Multipartite entanglement in the Fenna-Matthews-Olson (FMO) pigment-protein complex

Abstract

We investigate multipartite states in the Fenna-Matthews-Olson (FMO) pigment-protein complex of the green sulfur bacteria using a Lorentzian spectral density of the phonon reservoir fitted with typical parameter estimates of the species, Prosthecochloris aestuarii. The evolution of the entanglement measure of the excitonic W qubit states is evaluated in the picosecond time range, showing increased revivals in the non-Markovian regime. Similar trends are observed in the evolution dynamics of the Meyer-Wallach measure of the N-exciton multipartite state, with results showing that multipartite entanglement can last from 0.5 to 1 ps, between the bacteriochlorophylls of the FMO complex. The teleportation and quantum information splitting fidelities associated with the Greenberger-Horne-Zeilinger and W-like resource states formed by the excitonic qubit channels of the FMO complex show that revivals in fidelities increase with the degree of non-Markovian strength of the decoherent environment. Quantum information processing tasks involving teleportation followed by the decodification process involving W-like states of the FMO complex may play a critical role during coherent oscillations at physiological temperatures.

Natural light harvesting systems: unraveling the quantum puzzles

“…Multipartite states are generally fragile compared to bipartite states, and in this regard, appear unlikely to play a dominant role in the presence of decoherence effects in organic systems. However there have been predictions that such states can exist even at physiologically high temperatures [12,127] in solids, and play an important role in the quantum properties of molecular systems. Multipartite states are also of interest in photosynthetic systems, from the point of the "principle of quantum information causality", founded on the mathematical formulations of quantum information causality [128].…”

“…For instance, a qubit state associated with N > 2 subsystems is present in the multipartite state as |Ψ = N n=1 c n |0 ⊗(n−1) ⊗ |1 ⊗ |0 ⊗(N −n) (12) with coefficients c n , and |0 , |1 are orthonormal basis vectors of a two-dimensional state space. The symmetric Dicke state with just one excitation appear as…”

Non-Markovianity during the quantum Zeno effect

“…Further investigation is needed to seek a rigorous link between the efficient rate of energy transfer in light-harvesting systems and the mechanism by which the monitoring action of the dissipative sinks results in notable non-Markovian signatures in specific partitions of multipartite states. The latter states hold much relevance in large photosynthetic membranes which constitute many FMO complexes [69], with capacity to hold a large number of entangled excitonic qubits, when conditions for occurrence of initially correlated chromophores become favourable.…”

“…[68] presented results which showed the importance of incorporating the site energy based electronic coupling correlations. The increased oscillations of entanglement in the non-Markovian regime of intra-qubit systems in an earlier work [69] further highlighted the importance of feedback mechanisms in the FMO monomer system. However in all these works, there was focus only on the intra-qubit Markovian attribute, and to this end, the contributions from inter-qubit Markovian dynamics of photosynthetic systems need further study.…”

“…An important reason to consider inter-qubit Markovian dynamics is associated with the significance of multipartite states that act as sources of local and non-local correlations in large photosynthetic membranes which feature in many FMO complexes [69]. The intra-qubit Markovian (and non-Markovian) model, which is suitable for the FMO monomer, is less applicable in the examination of quantum correlations and exchanges across a wider networked molecular system with capacity to hold a large number of entangled excitonic qubits.…”