Typically, quantum mechanics studies the behavior of energy and matter at the atomic scale, but a German-Spanish research group has begun looking for ways to detect quantum properties in more complex and larger entities – possibly even living organisms. This illustration shows the protocol to create quantum superposition states applied to living organisms, such as viruses, trapped in a high-finesse optical cavity by optical tweezers. (Image: New Journal of Physics) The group, split between Max Planck Institute for Quantum Optics in Garching and the Institute of Photonic Sciences (ICFO), is using the principles of an iconic quantum mechanics thought experiment – Schrödinger’s superpositioned cat – to test for quantum properties in objects composed of as many as 1 billion atoms, possibly including the flu virus. Quantum optics is a field well-rehearsed in the process of detecting quantum properties in single atoms and some small molecules, but the scale that these researchers wish to work at is unprecedented. When physicists try to fathom exactly how the tiniest constituents of matter and energy behave, confusing patterns of their ability to do two things at once (referred to as being in a superposition state), and of their "spooky" connection (referred to as entanglement) to their physically distant subatomic brethren, emerge. It is the ability of these tiny objects to do two things at once that Oriol Romero-Isart and his co-workers are preparing to probe. With this new technique, the researchers suggest that viruses are one type of object that could be probed. Albeit speculatively, the researchers hope that their technique might offer a route to experimentally address questions such as the role of life and consciousness in quantum mechanics. To test for superposition states, the experiment involves finely tuning lasers to capture larger objects such as viruses in an "optical cavity" (a very tiny space), another laser to slow down the object (and put it into what quantum mechanics calls a "ground state") and then adding a photon in a specific quantum state to the laser to provoke it into a superposition "We hope that this system, apart from providing new quantum technology, will allow us to test quantum mechanics at larger scales, by preparing macroscopic superpositions of objects at the nano- and microscale. This could then enable us to use more complex microorganisms, and thus test the quantum superposition principle with living organisms by performing quantum optics experiments with them," the researchers say. The new research was published in New Journal of Physics (co-owned by the Institute of Physics and German Physical Society). For more information, visit: www.mpq.mpg.de