As if entangled quantum particles — what Einstein called “spooky particles at a distance” — weren’t strange enough, researchers from Chapman University in Orange, California, have shown mathematically that any two particles in the universe could be linked together, even if they’ve never interacted before … simply by measuring their quantum properties.
But in a twist that raises questions about the very nature of time, they also found that the properties of a system can be affected by measurements made in the future, what they refer to as “post-selection.”
“Is that mind-blowing or is that mind-blowing?” said Jeff Tollaksen, one of the researchers, in an interview with New Scientist.
To back up their mind-blowing claims, the researchers came up with a thought experiment known as the “quantum pigeonhole effect.” Normally, if you had three pigeons to house and only two pigeonholes, two of the birds would need to share a room … but not if they are electrons that have been “post-selected.”
To test out this effect, send three electrons through an interferometer—a device that splits each particle into two, sends them down two paths at the same time, and then rejoins them on the other side. Under normal circumstances, two electrons following the same path will repel each other, something that is easily detected.
To avoid this, say the researchers, you can post-select the electrons by measuring their state when they exit the interferometer — basically influencing the past by measuring the present. If you choose the right measurement, the electrons will avoid each other inside the interferometer—a sign of their quantum linkage.
While real-world tests still have to be done, the researchers think that particles everywhere in the universe could be correlated in this way, both through human measurements and natural interactions, even as a result of those that have yet to happen.