Quantum states last longer in birds' eyes: These oscillating magnetic fields will only disrupt the birds' magnetic compass while the electrons remain entangled. As a weaker magnetic field takes longer to alter an electron's spin, the team calculated that for such tiny fields to have such a strong impact on the birds' compasses the electrons must remain entangled for at least 100 microseconds. Their work will appear in Physical Review Letters.
The longest-lived electrons in an artificial quantum system - a cage of carbon atoms with a nitrogen atom at its centre - survived for just 80 microseconds at comparable temperatures, the team points out. "Nature has, for whatever reason, been able to protect quantum coherence better than we can do with molecules that have been specially designed," says team member Simon Benjamin of the Centre for Quantum Technologies in Singapore.