My name is Dr. Joe Britton, I'm a postdoctoral fellow at the National Institute of Standards and Technology in Boulder, Colorado, and I'm going to be telling you about my research in quantum simulation using trapped ions.
A quantum simulator is a system which can be made to mimic the behavior of another quantum mechanical system which is poorly understood.
The penning trap simulator confines about 350 trapped beryllium ions, and they're confined using a combination of static electric and magnetic fields. These ions can form a two-dimensional crystal. So this is a crystal which is a single layer thick, and the ions form a triangular lattice in this crystal.
Each of the ions is a quantum bit, or a qubit, and you can think of this as a tiny bar magnet which is either aligned with or anti-aligned with an external magnetic field. And the quantum bit, in our case, can be made to interact with its neighbors in a fashion which resembles the interaction of natural, of atoms in natural materials, how they interact with their neighbors.
So this single plane of ions is about a millimeter in diameter. And in our trap it undergoes a vibrational motion similar to what happens on a drumhead.
The vibrational motion is described in this animation. At the top of the animation, you see the motion of the drumhead where all of the ions are moving in the unison. And in the next two images you see motion where the ion crystal is tilting, and where it's undergoing flexural motion. At the bottom of the animation adjacent ions are moving out of phase with one another, in opposite directions.
The joint motion of the ions is the mechanism by which we couple them to one another, and cause them to mimic the behavior of natural solids.
Many scientists have worked for the last 10 years to build quantum simulators. And thus far the simulators have been toy models of sorts – that is, nothing about them couldn't be calculated on a conventional computer.
What's distinctive about the experiments which we're doing at NIST is that our simulator consists of 300 to 350 qubits that can be made to simultaneously interact with one another. Further, the geometry of this crystal is two-dimensional. Prior quantum simulators involved qubits that were arrayed in only one dimension. Finally, the interactions which we can generate between the qubits range over not just nearest neighbor interactions but also long-range interactions. Long range interactions are believed to be important for both superconductivity at high temperatures and also materials like ferromagnets.