Jon Simon: Building Quantum Materials

by Ted Jou '99

Jon Simon ’00 is an Assistant Professor of Physics at the University of Chicago. This spring, Pf. Simon was honored with a Presidential Early Career Award for Scientists and Engineers. He had previously been recognized by the Department of Energy with a Young Investigator Award, but he did not know that he had been recommended for a Presidential Award until he received a mysterious e-mail asking for permission to do a background check. In May, he traveled back to the DC area with about 100 of the top young researchers in the country to meet President Obama at the White House.

Pf. Simon’s goal is to develop a quantum “erector set” to build materials from the ground up starting with individual particles. While other researchers have observed the effects of quantum entanglement in existing materials, Pf. Simon’s lab is making models of materials one particle at a time to “explore the entanglement that starts to arise between the particles.”

The particles that Pf. Simon uses to make his materials are ultracold atoms in lattices of laser beams or photons trapped between mirrors. In his lab, he can manipulate individual photons, and his group is working towards creating “materials” made of a handful of photons in a crystalline structure. While a superconductor is a crystal made up of atoms, Pf. Simon wants to build crystals made of light itself, where photons are arranged in a lattice and can behave like a solid.

Pf. Simon’s lab is working to build synthetic quantum materials, which can be used to help understand the exotic behavior of materials like superconductors. In contrast to normal electrical conductors, which can be modeled as transporting electrons that are independent objects, a superconductor can transport electrons without any resistive losses. Pf. Simon is developing new ways to study phenomena like this which harness quantum entanglement of electrons. Modeling these systems on a macroscopic scale is difficult. Although physicists understand at a fundamental level how quantum mechanics works, Pf. Simon explains that when you try to put together many quantum mechanical particles, “you can’t solve the equations and the behavior of the system becomes very bizarre and exotic.” These materials have been studied in the field of condensed-matter physics, where solids are cooled down to very cold temperatures to observe quantum fluctuations, but “it is not always clear what is happening at the atomic level.”

Pf. Simon’s lab uses specially curved “super-mirrors” that can trap photons for tens of thousands of reflections – like mirrors on the walls of a barbershop. By changing the arrangement and curvature of these mirrors, he can make photons behave in specific ways, imbuing them with mass and applying magnetic fields to them. The mirrors that hold the photons are only about a centimeter apart, but the entire apparatus spans three rooms. This includes equipment to cool atoms down close to absolute zero using lasers and magnetic fields, chambers and pumps to maintain the experiment in vacuum, and lasers to transport the photons between the mirrors.

Pf. Simon was a co-author on a recently published letter in Nature, "Synthetic Landau levels for photons," describing an experiment where several mirrors were arranged like a periscope, which rotated the photons on every round-trip. This rotation creates Coriolis/Lorentz and centrifugal forces on the photons, which is similar to what a charged particle experiences in a magnetic field. The photons exhibit signatures of the quantum Hall effect, and this could be useful for characterizing a type of quantum computer.

As a professor, Pf. Simon has taught an undergraduate lab course and graduate courses in condensed-matter and atomic physics. He says that his own teaching experience “has given me an incredible appreciation for my teachers and the wonderful job they did in the Magnet.” He has tried to give his own students an experience like the Magnet where lessons were reinforced in different classes – learning about gravitational forces in Physics with Mr. Donaldson, modeling it in computer science with Ms. Piper, and conducting an experiment in R&E with Mr. Johnson. But outside of his research group this has been difficult, as he has learned that “there are only so many hours in a day” to plan and coordinate between different classes.

When he looks back on his high school experience, Pf. Simon remembers many formative experiences, going back to Functions: “Through general relativity and quantum field theory, I don’t think I’ve struggled as much as I did in Ms. Dyas’s class.” Those struggles “taught me what it meant to know something – the difference between memorizing and knowing.” From Mr. Donaldson, he got “a fantastic sense of the wonder of the physical world.” Mr. Johnson and Mr. Curran nurtured a “love of building things,” and Mr. Walstein a “love of mathematics.” He remembers hating how Ms. Piper would force him to work out simulations in Stella by hand before going on the computer, but he teaches those same lessons to his students today to help them to understand how a system changes step-by-step, and “how the next instant of time is dependent on the last.”

Pf. Simon sees a lot of the interdisciplinary influences of the Magnet on his current research. In his lab, he enjoys having “the opportunity to calculate things from first principles, and then to build them and explore the physics in a cutting-edge lab.” As he alternates between solving equations, running computer models, and soldering electronics, he is reminded of some of his favorite experiences in the Magnet, learning and tinkering and discovering more about how the world works.