Schrödinger’s microbe

A common microbe could soon be living in two places at once like Schrödinger’s cat in the baffling quantum theory thought experiment.

The rules of quantum mechanics allow for objects to be in a “superposition” of two different states at once – one of the foundational ideas of quantum computing. It was explained beautifully by quantum computing pioneer Andrea Morello in Cosmos magazine last year – see The Quantum Spinmeister.

Quantum theorist Erwin Schrödinger in 1935 tried to explain the concept differently using a thought experiment in which cat found itself in a closed box with a small radioactive source, a Geiger counter, a hammer and a bottle of poison. If the radioactive source decayed, the Geiger counter would trigger the release of the poison. In quantum mechanics, the state of the cat would be “entangled” with the state of the radioactive material – the cat would be in a superposition of both alive and dead states.

Physicists now aim to suspend a microbe in an uncertain state, the uncertainty in this case will be its geographical position.

“Although it has attracted enormous interest, no quantum superposition state of an organism has been realized. So we propose a straightforward approach to put a microbe into a superposition of two spatial states, that is, the microbe will be at two different positions at the same time,” Tongcang Li of Purdue University, Indiana, told the Guardian.

“We propose to simply put a small microbe on top of the aluminum membrane. The microbe will also be in a superposition state when the aluminum membrane is in a superposition state. The principle is quite simple,” Dr Li said.

The researchers plan to go one step further in a second experiment that would entangle the position of the microbe with the spin of an electron inside it. “The purpose of the second experiment is to make the system useful. It can be used to detect defects of DNA and proteins in a microbe, and image the microbe with single electron spin sensitivity,” Dr Li said.