QUANTUM weirdness could soon invade the living world, if a scheme to give a a strange double life comes off. The method might work on more complex life forms too.
In quantum theory, a single object can be doing two different things at once. This so-called “superposition” is a delicate state, destroyed by any contact with the outside world. The largest objects that have been superposed so far are molecules. It is hard to put a much larger object such as a cat or human into a superposition because air molecules and photons are always bouncing off it.
But it might be possible with a small life form, according to of the Max Planck Institute for Quantum Optics in Garching, Germany, and his colleagues. They chose the flu virus because it can survive in a vacuum – solving the problem of pesky air molecules.
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Their scheme would use two laser beams, whose light exerts a gentle force on matter. Where the two beams cross they form an “optical cavity” holding the virus in place. By adjusting the frequency of the beams, the laser photons can be made to absorb the vibration energy of the trapped virus until it is slowed to its lowest possible energy state. In this “ground state” the virus is ready to go into a superposition.
Sending a laser photon towards the trap should do the trick. Since a photon is a quantum entity it has more than one option open to it. Thus it will be both reflected and transmitted at the trap, putting it into a superposition. By impinging on the virus, it forces it into a superposition of both its ground state and next vibrational energy state. Now the virus should be doing two different things at once, the equivalent of you simultaneously mowing the lawn and doing the shopping. “They have come up with a really neat experiment – inventive and I think feasible,” says of Imperial College London.
“The virus should be both vibrating and not vibrating, the equivalent of mowing the lawn and shopping”
Romero-Isart and his colleagues speculate that they could pull off the same feat with a tardigrade, or water bear, an animal less than a millimetre in size that can survive extreme temperatures and a vacuum for several days. Such experiments could answer one fundamental question – is there a size or mass above which objects cease to be quantum?