Given all the weird things that can occur in quantum mechanics—from entanglement to superposition to teleportation—not much seems surprising in the quantum world. Nevertheless, a new finding that an object’s physical properties can be disembodied from the object itself is not something we’re used to seeing on an everyday basis. In a new paper, physicists have theoretically shown that this phenomenon, which they call a quantum Cheshire Cat, is an inherent feature of quantum mechanics and could prove useful for performing precise quantum measurements by removing unwanted properties.
Just as the grin is a property of a cat, polarization is a property of a photon. In their paper, the physicists explain how, “in the curious way of quantum mechanics, photon polarization may exist where there is no photon at all.”
They’re saying it should be possible to separate the grin from the cat (as the Cheshire Cat was in the habit of doing, in Alice in Wonderland), and both still exist.
Hat tip: The Battlefield