Physicists introduce another quantum animal: The Quantum Pigeon

Recently physicists at Chapman University's Institute for Quantum Studies introduced the Quantum Cheshire Cat. Now they have introduced another quantum animal: the Quantum Pigeon.

In the 20th century, two revolutions in physics shook the world. One of them was relativity, discovered by Einstein. It revealed that spacetime is not what we experience in everyday life. For example, if you travel close to the speed of light, then you will age more slowly than somebody who stays on Earth.

The second revolution was quantum theory, the microscopic theory of particles, such as electrons, atoms, or photons. Quantum theory showed that nature is not deterministic—as Einstein put it, "God plays with dice." After a century of careful testing, most physicists believe that the "chanciness" or "capriciousness" of the microscopic world is fundamental.

One of the most exotic aspects of nature is quantum non-locality which was first discovered more than four decades ago. It is referred to as "the most profound discovery of science."

There are different types of non-locality which quantum mechanics showed could not exist in classical physics. In classical physics for a particle to experience a force, it must be at the same location where the force is. In quantum mechanics you can have a force in one place while the particle moves outside. Nevertheless, the particle will still feel this force. This is called the Aharonov-Bohm effect.

There is another kind of non-locality that has to do with the relation between two particles that used to be next to each other in the past and then subsequently were separated to a large distance. Even after they were separated far apart, they appeared to maintain a strange kind of connection—what Einstein called "spooky action at a distance." However, these surprising kinds of connections had many limitations. For example, the particles had to originally be next to each other and only a relatively small number of particles in the universe could be connected with each other at a time.

While the above was remarkable enough, now it appears this was only part of the story as demonstrated in a recent paper by a team from the Institute for Quantum Studies at Chapman University co-authored by Yakir Aharonov, Fabrizio Colombo, Sandu Popescu, Irene Sabadini, Daniele Struppa, and Jeff Tollaksen. They introduced a new kind of quantum connectivity between particles which transcends these limitations. This connectivity is happening all the time on a much bigger, cosmic scale.