Schrödinger’s Bacterium: Researchers Plan to Put a Living Organism in Two Places at Once

Eighty years ago Austrian physicist Erwin Schrödinger put forward a now-famous thought experiment demonstrating the ‘absurdity’ of quantum physics. He (theoretically) placed a cat, a flask of poison, and a radioactive source in a sealed box. If an internal monitor detected the radioactivity from a single atom decaying, the poison would be released into the box, killing the cat. But in the weird world of quantum mechanics (or at least the ‘Copenhagen Interpretation’) the cat would supposedly remain in a state of ‘superposition’, both alive and dead, until an observation or measurement was made by an external observer opening the box, collapsing the wavefunction.

Schrödinger did not see his thought experiment as a serious possibility – instead, it was meant to show the problems with the Copenhagen interpretation. But eight decades on two researchers have put forward a serious suggestion to place a living organism – albeit a tiny bacterium, rather than a cat – in a state of superposition, effectively making it exist in two places at the same time. The proposed experiment builds on a 2013 paper in which the successful superposition of a macroscopic aluminium membrane was detailed.

According to the researchers, they propose…

…to create quantum superposition and entangled states of a living microorganism by putting a small bacterium on top of an electromechanical oscillator, such as a membrane embedded in a superconducting microwave resonant circuit. Our proposal also works for viruses. Since many biologists do not consider viruses as living organisms, we focus on small bacteria in this paper. [M]ost microorganisms can survive in the cryogenic environment that is required to achieve ground state cooling of an electromechanical oscillator. Although microorganisms are frozen in a cryogenic environment, they can be still living and become active after thawing. Cryopreservation is a mature technology that has been used clinically worldwide. Most microorganisms can be preserved for many years in cryogenic environments.

…This will be remarkably similar to Schrödinger initial thought experiment of entangling the state of an entire organism (‘alive’ or ‘dead’ state of a cat) with the state of a microscopic particle (a
radioactive atom).

In an interview with The Guardian, Tongcang Li of Purdue University noted that “in many fairy tales, a fairy could be at two different locations or change locations instantly. This will be similar to that. Although it will be a microbe instead of a fairy.”

“It will be the first experiment to put an organism into a quantum superposition state,” he added.