A team of international physicists discovered that photosynthetic molecules exhibit the same quantum effects as non-biological systems.

Researchers say this finding could help explore light-harvesting mechanical devices in the future.

Quantum Molecules

Scientists previously suggested that quantum molecules in biological systems behave the same as those in nonliving objects. This effect is shown in the experiment of Schrödinger's Cat. The idea is that electrons can be in two states at a single time, being both "dead" and "alive," until such time that it is observed.

This behavior is verified through other studies on light-harvesting molecules in bacteria where the excitatory state of the electrons is measured at about 1 picosecond.

On the other hand, Thomas la Cour Jansen, theoretical physicist from the University of Groningen in the Netherlands said this observation was wrong and suggested that the movements were "regular vibrations of the molecules."

Details of the study was published in the May 21 edition of Nature Chemistry.

Testing The Hypothesis

To validate their hypothesis, Jansen and his team used various light polarization in the measurement of light harvesting green sulfur bacteria. The bacteria are made up of seven light-sensitive photosynthetic molecules. The goal is to use a photon to excite two of these molecules, resembling the effect of the Schrödinger's Cat.

"In the case of such a superposition, spectroscopy should show a specific oscillating signal," Jansen explained. "Furthermore, we found quantum effects that lasted precisely as long as one would expect based on theory and proved that these belong to energy superimposed on two molecules simultaneously."

Jansen added the results may have a significant impact on the development of new systems such as solar energy storage and quantum computers.

Geometric Chlorophyll Structure

In a 2016 study published in The Journal of Physical Chemistry Letters, researchers at the University of Queensland in Australia discovered that certain purple bacteria an exceptional geometric structure for light harvesting during photosynthesis.

Ivan Kassal, the lead author of the study and a researcher at the ARC Center of Excellence for Engineered Quantum Systems, reported that the chlorophyll molecules are arranged in symmetrical rings.

"By understanding how the purple bacteria harvest light, we may be able to use these lessons to improve how we do artificial light harvesting," said Kassal. "We found that the geometry adopted by the purple bacteria allows for quantum coherence."

Kassal added that their findings provide a "fertile ground" to develop quantum-based technologies that mimic nature activities.