NIST Physicists Demonstrate Quantum Entanglement in Mechanical System -- animation captioning

This animation shows how we entangle the mechanical motion of two pairs of trapped ions. Our experiment uses two types of ions, one of which is a beryllium ion.

The beryllium ion has an internal state denoted by the arrow. The arrow can either be pointing up or it can be pointing down. A quantum super position of up and down is shown as the arrow spinning.

For this experiment, we will need another beryllium ion. If you have two or more ions together, then their motion will behave like they are connected by a spring … and they will oscillate back and forth.

We will also need two magnesium ions which will be used to re-cool the ions’ motion when they get hot.

The first step is to entangle the internal states of the beryllium ions. The entanglement is shown as both arrows spinning together.

The next step is to distribute the entangled ions to two different locations. The separation process excites the motion of the ion pairs. Lasers cool the magnesium ions, which sympathetically cool the beryllium ions.

The next step is to transfer the internal entanglement onto the motion. This is first done on the pair on the left. Next, the internal entanglement is transferred to the motion of the pair on the right.

We now have entangled the mechanical motion of the two pairs of ions to create two, entangled mechanical oscillators.