Does the nature know about and use quantum effects more than we do?
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SYDNEY: Quantum effects are used to absorb and move around light energy during photosynthesis, scientists said, and its the first time such long-lived effects have been seen in this temperature range.
Photosynthesis is crucial to the evolution of life, but until now the way that proteins harness the energy of sunlight so effectively has long been a mystery.
Scientists have shown that two species of marine algae use a quantum state known as coherence — where light strangely exists in two places at once — to capture and transfer energy, and their results were published in the journal Nature today.
Harvesting light in solar cells
The results reveal how biological processes such as photosynthesis utilise quantum mechanics in order to survive and open up new possibilities towards harvesting light using 'organic' solar cells.
A team of scientists led by Australian chemist Greg Scholes, currently at the University of Toronto in Canada, isolated light-harvesting proteins in marine algae called cryptophytes. They stimulated the proteins with femtosecond laser pulses to mimic the absorption of sunlight.
"This enabled us to monitor the subsequent processes, including the movement of energy between special molecules bound in the protein, against a stop-clock," said Scholes.
"We were astonished to find clear evidence of long-lived quantum mechanical states involved in moving the energy.
Proteins use 'superposition'
"Our result suggests that the energy of absorbed light resides in two places at once - a quantum superposition state, or coherence - and such a state lies at the heart of quantum mechanical theory," he said.
Light-harvesting proteins are a crucial feature of photosynthesis and allow organisms to most effectively capture sunlight across a broad spectrum.
Although the functions of these proteins in photosynthesis have been observed before, this is the first time such long-lived quantum coherence has been observed at a normal temperature range.
