PORTLAND, Ore. Physicists at the National Institute of Standards and Technology have synchronized the motions of two nano-pendulums by virtue of a quantum phenomenon called entanglement what Albert Einstein called "spooky action at a distance."
Quantum entanglement keeps atoms, electrons and photons in synchronized states no matter how far they are moved apart. Entanglement is to communications what "Beam me up Scotty" is to transportation a kind of faster-than-light connection that instantaneously links entangled atoms regardless of distance.
"We have shown that the same sort of mechanical oscillations that we see in, for instance, a pendulum in the macroscopic world, can be entangled too, "said NIST guest researcher John Jost, a doctoral candidate at the University of Colorado (Boulder).
|An artistic representation of two entangled mechanical oscillators consisting of two pairs of trapped ions. The arrows denote the internal state of two of the ions. The mist between the two oscillators is used to represent the entanglement.|
Credits: Created by John Jost with help from Jason Amini
The NIST nano-pendulum consisted of two ions four microns apartcharged beryllium and magnesium atomsoscillating in perfect synchronization with another spatially separated pair of entangled ions 240 microns away. First they used pulsed lasers to cool the atoms in an electrostatic trap between two parallel facing electrodes. Then they used a pulsed laser to entangle the spin states of the two beryllium atoms, and another pulsed laser to transfer that spin state to the pendulum-like oscillation motion between the two ions.
The researchers then physically separated the two groups of synchronized oscillating ions into different electrostatic traps, and showed that the quantum states could be stored in their physical motion, then later transferred back to the spin state of the beryllium ion. The entire experiment takes about 600 laser pulses and about 14 milliseconds.
"Other groups are working toward demonstrating entangled oscillation in small beams made of thousands or millions of atoms a top-down approach," said Jost. "But we wanted to use the bottom-up approach, where we demonstrate entanglement of mechanical oscillations between individual atoms and then move up toward macroscopic sizes."
The main objective of the NIST research group is fostering practical quantum computing architectures.
"We demonstrated for the first time that you can use pulsed lasers to cool down quantum devices without destroying their states," said Jost. "Quantum computers inevitably heat up when operating, so they will need to be cooled using something like the technique we demonstrated."
Funding was provided by the Intelligence Advanced Research Projects Activity.