Robins keep the quantum entanglement in their eyes for 20 microseconds longer than the best laboratory systems. This is the conclusion of physics, which explored how birds use quantum effects to "see" the Earth’s magnetic field.
Quantum entanglement - a state of electrons, which are separated in space, but continue to influence each other. Put forward the theory that in the eyes of the birds built compasses, acting on the basis of entanglement.
"As a living system could evolve to learn to maintain inside the quantum state just as good or even better than in the laboratory," - asks the quantum physicist Simon Benjamin of Oxford University and the National University of Singapore, co-author of the new study. "It’s really amazing."
Many of the animals, not just birds but also mammals, fish, reptiles, and even insects and crustaceans - determine the route of movement by the magnetic field of the Earth. Physicist Klaus Schulten of the University of Illinois, has put forward the theory that birds orient themselves in space by some biomagnetic reactions in their eyes, which are not yet open.
Investigation has revealed the presence of specific light-sensitive cells containing protein called cryptochrome. When a photon enters the eye, it interacts with the cryptochrome, transferring some energy to the electrons, which are in a state of entanglement.
One of these electrons is moved to a few nanometers, which feels a magnetic field, which is slightly different from the one in which he is a partner. Type of chemical reactions varies depending upon the magnetic field changes the electron spin. In theory, as a result of many such reactions in the eye of the bird creates an image of the magnetic field of the Earth in the form of black-and-white pattern.
But these quantum states are extremely fragile. Even in the laboratory, where the atoms are cooled to almost absolute zero, the state of entanglement can hold only for a few thousandths of a second. Biological systems are too warm and wet to keep the quantum state for so long, but somehow they manage this is done.
The study, which was led by Thorsten Ritz of the University of California, conducted in 2004, found that robins can easily find directions to Africa by the magnetic field of the Earth, but when added to a second magnetic field, it is forced down their internal compass. This is the second field was so weak - less than 1 percent of the third field of the Earth, which could influence only on the quantum system.
Scientists estimate that this sensitivity to weak fields, requires retention of entanglement in the state for at least 100 microseconds or 0.00001 seconds. "It’s just amazing," - said Benjamin.