Thursday 19 June 2014

Algae Turns Its Internal Quantum Computer On and Off


 
Photosynthetic algae make the most of the energy they receive and then deliver that energy from leaves with near perfect efficiency.
 
Scientists have shown that certain algae which use quantum effects to optimize photosynthesis are also capable of switching it off. It's a discovery that could lead to highly efficient organic solar cells and quantum-based electronics.
Like quantum computers, some organisms are capable of scanning all possible options in order to choose the most efficient path or solution. For plants and some photosynthetic algae, this means the ability to make the most of the energy they receive and then deliver that energy from leaves with near perfect efficiency. This effect, called quantum decoherence, is what allows some algae to survive in very low levels of light.

Recently, scientists from the UNSW School of Physics studied one of these algae, a tiny single-celled organism called cryptophytes. They typically live at the bottom of pools of water, or under thick ice, where light is scarce. The researchers found that there's a class of cryptophytes in which quantum decoherence is switched off, and it's on account of a single genetic mutation that alters the shape of a light-harvesting protein.
In quantum mechanics, a system is coherent when all quantum waves are in step with each other. When it's coherent, it can exist in many different states simultaneously, an effect known as superposition.
The researchers used X-ray crystallography to determine the crystal structure of the light-harvesting complexes from three different species. Two cryptophyte species had a mutation that led to the insertion of an extra amino acid that changes the structure of the protein complex, which disrupts decoherence.

Original article appeared on iO9; all rights reserved.