One of the more exciting discoveries in biology in the last few years is the role that quantum effects seem to play in many living systems. 

The two most famous examples are in bird navigation, where the quantum zeno effect seems to help determine the direction of the Earth's magnetic field, and in photosynthesis, where the way energy passes across giant protein matrices seems to depend on long-lasting quantum coherence.   

Despite the growing evidence in these cases, many physicists are uneasy, however. The problem is the issue of decoherence, how quickly quantum states can survive before they are overwhelmed by the hot, wet environment inside living things

Quantum biology on the edge of quantum chaos

We give a new explanation for why some biological systems can stay quantum coherent for long times at room temperatures, one of the fundamental puzzles of quantum biology. We show that systems with the right level of complexity between chaos and regularity can increase their coherence time by orders of magnitude. Systems near Critical Quantum Chaos or Metal-Insulator Transition (MIT) can have long coherence times and coherent transport at the same time. The new theory tested in a realistic light harvesting system model can reproduce the scaling of critical fluctuations reported in recent experiments. Scaling of return probability in the FMO light harvesting complex shows the signs of universal return probability decay observed at critical MIT. The results may open up new possibilities to design low loss energy and information transport systems in this Poised Realm hovering reversibly between quantum coherence and classicality.