Quantum coherence in photosynthetic complexes

2011 ◽  
Vol 248 (4) ◽  
pp. 833-838 ◽  
Author(s):  
Tessa R. Calhoun ◽  
Graham R. Fleming
2011 ◽  
Vol 115 (6) ◽  
pp. 1531-1537 ◽  
Author(s):  
Jing Zhu ◽  
Sabre Kais ◽  
Patrick Rebentrost ◽  
Alán Aspuru-Guzik

2014 ◽  
Vol 89 (4) ◽  
Author(s):  
Hong-Bin Chen ◽  
Jiun-Yi Lien ◽  
Chi-Chuan Hwang ◽  
Yueh-Nan Chen

2021 ◽  
Vol 7 (8) ◽  
pp. eabc4631
Author(s):  
Elinor Zerah Harush ◽  
Yonatan Dubi

Answering the titular question has become a central motivation in the field of quantum biology, ever since the idea was raised following a series of experiments demonstrating wave-like behavior in photosynthetic complexes. Here, we report a direct evaluation of the effect of quantum coherence on the efficiency of three natural complexes. An open quantum systems approach allows us to simultaneously identify their level of “quantumness” and efficiency, under natural physiological conditions. We show that these systems reside in a mixed quantum-classical regime, characterized by dephasing-assisted transport. Yet, we find that the change in efficiency at this regime is minute at best, implying that the presence of quantum coherence does not play a substantial role in enhancing efficiency. However, in this regime, efficiency is independent of any structural parameters, suggesting that evolution may have driven natural complexes to their parameter regime to “design” their structure for other uses.


Author(s):  
A. W. Chin ◽  
S. F. Huelga ◽  
M. B. Plenio

The quantum dynamics of transport networks in the presence of noisy environments has recently received renewed attention with the discovery of long-lived coherences in different photosynthetic complexes. This experimental evidence has raised two fundamental questions: firstly, what are the mechanisms supporting long-lived coherences; and, secondly, how can we assess the possible functional role that the interplay of noise and quantum coherence might play in the seemingly optimal operation of biological systems under natural conditions? Here, we review recent results, illuminate them by means of two paradigmatic systems (the Fenna–Matthew–Olson complex and the light-harvesting complex LHII) and present new progress on both questions.


2010 ◽  
Vol 107 (29) ◽  
pp. 12766-12770 ◽  
Author(s):  
G. Panitchayangkoon ◽  
D. Hayes ◽  
K. A. Fransted ◽  
J. R. Caram ◽  
E. Harel ◽  
...  

Author(s):  
Ana Maria Ariciu ◽  
David H. Woen ◽  
Daniel N. Huh ◽  
Lydia Nodaraki ◽  
Andreas Kostopoulos ◽  
...  

Using electron spins within molecules for quantum information processing (QIP) was first proposed by Leuenberger and Loss (1), who showed how the Grover algorithm could be mapped onto a Mn12 cage (2). Since then several groups have examined two-level (S = ½) molecular spin systems as possible qubits (3-12). There has also been a report of the implementation of the Grover algorithm in a four-level molecular qudit (13). A major challenge is to protect the spin qubit from noise that causes loss of phase information; strategies to minimize the impact of noise on qubits can be categorized as corrective, reductive, or protective. Corrective approaches allow noise and correct for its impact on the qubit using advanced microwave pulse sequences (3). Reductive approaches reduce the noise by minimising the number of nearby nuclear spins (7-11), and increasing the rigidity of molecules to minimise the effect of vibrations (which can cause a fluctuating magnetic field via spin-orbit coupling) (9,11); this is essentially engineering the ligand shell surrounding the electron spin. A protective approach would seek to make the qubit less sensitive to noise: an example of the protective approach is the use of clock transitions to render spin states immune to magnetic fields at first order (12). Here we present a further protective method that would complement reductive and corrective approaches to enhancing quantum coherence in molecular qubits. The target is a molecular spin qubit with an effective 2S ground state: we achieve this with a family of divalent rare-earth molecules that have negligible magnetic anisotropy such that the isotropic nature of the electron spin renders the qubit markedly less sensitive to magnetic noise, allowing coherent spin manipulations even at room temperature. If combined with the other strategies, we believe this could lead to molecular qubits with substantial advantages over competing qubit proposals.<br>


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