Few phenomena in quantum physics seem as close to magic as entanglement. Einstein called it "spooky action at a distance," and harnessing it might one day make teleportation a reality. Entanglement is anti-intuitive, fantastical, and weird, but the science behind it is extremely well established.
It essentially involves placing two seemingly separate particles in a correlated state, such that changes made to one particle will instantaneously also influence changes to the other, even if the two particles are separated by great distances. Theoretically, two entangled particles can remain correlated even if they are on opposite sides of the universe from one another.
The only catch? Entanglement only seems to work on the smallest of scales, on things like photons or atoms. It seems restricted to the quantum realm, at least on a practical level. That's not to say that entanglement on the macroscopic level is theoretically inconceivable, but just that when you scale things up, the world gets more complicated. There's more noise and interference, and quantum states collapse; they buckle under the weight.
But a breakthrough new experiment could soon change everything we thought we knew about the limitations of quantum entanglement. In a paper recently published in the journal Nature, researchers outline a successful effort to entangle two macroscopic objects — objects made up of trillions of atoms — that approach the level visible to the naked human eye, reports The Conversation.
It's a game-changer. The macroscopic objects in question are two microfabricated vibrating circular membranes. Basically, they're tiny drumheads that measure at about the width of a human hair. That might still seem small, but it's huge by quantum comparisons. It's also something we can see with our own eyes, albeit strained eyes.
Researchers were able to bring the two tiny drums into a state of entanglement through the careful driving of a superconducting electrical circuit to which both were coupled. They kept the noise from the great big world at bay by cooling the electrical circuit to just above absolute zero, about minus 273 degrees Celsius (minus 459.4 degrees Fahrenheit). Amazingly, the two drums remained entangled for almost half an hour.
The implications of this research are monumental. It could lead to new discoveries about how gravity and quantum mechanics work together. It could lead to breakthroughs in quantum computing via the instantaneous teleportation of macroscopic mechanical vibrations. It could even give us greater confidence that the laws of quantum physics do indeed apply to large objects, thus ushering in an era of controlled, but seemingly spooky technology.
"It is clear that the era of massive quantum machines has arrived," explained Matt Woolley, one of the researchers on the team. "And is here to stay."