BOZEMAN – A Montana State University physicist who studies the interactions between light and matter has received a prestigious Air Force Office of Scientific Research award for basic research on atom-photon interactions that could lead to advances in quantum computing and quantum sensing.
Matt Jaffe, an assistant professor in MSU’s Department of Physics in the College of Letters and Science , will receive $150,000 in research funding each year for three years from the Air Force’s Young Investigator Program. The program is intended to support early-in-career scientists and engineers who show exceptional ability and promise for basic research.
“This prestigious award recognizes Matt as an outstanding researcher and mentor in an area of science that is of fundamental and strategic importance,” said John Neumeier, head of the physics department. “We are certain that Matt’s research will lead to significant discoveries in the field of atomic and molecular physics and are very pleased to have him at MSU.”
The Air Force funding will cover Jaffe’s investigation into the feasibility of changing how atoms and light interact in an optical cavity to facilitate innovative quantum applications. Optical cavities, also called optical resonators, are devices in which scientists bounce beams of light back and forth between mirrors.
Jaffe’s research group has discovered that by manipulating the placement of mirrors and lenses inside cavities, it’s possible to modify the usual shape of light beams to change the way they interact with atoms. A flattened laser beam, for example, could control atoms in a cavity more precisely and uniformly than the typically bell-shaped paraxial and Gaussian laser beams, which diffract and expand. However, the process isn’t quite as simple as it sounds, Jaffe said.
“It turns out that just using the regular kind of lenses and mirrors doesn’t do it – it just turns Gaussian beams into Gaussian beams,” he said. “But we’ve come up with a way of calculating and describing these beyond the simplest description. That allows us to design cavities that can host these non-Gaussian, non-paraxial beam shapes.”
Jaffe, along with two students whose work is funded by the award, will attempt to harness the manipulated beams to carry out specific tasks.
For the quantum computing application, they will investigate transferring qubits stored inside single atoms into single particles of light called photons. Qubits are the base units of data in quantum computing, but scientists haven’t yet figured out how to link and transmit them efficiently between two remote nodes through a process called entanglement distribution. Jaffe said that distributing entanglement, the “quantum resource” of quantum computation, is necessary for scaling quantum computing devices to a useful size.
“In order to wire arrays of neutral atom qubits up to each other, we’d like to write their quantum information out using photons, which can travel through optical fibers,” he said. “Photons from multiple modules can then link up to form a larger quantum processor out of this array of submodules.”
The sensing application – a new method of measuring gravity very precisely – would use light differently. Instead of transporting information, light would build up inside the cavity, resulting in a clean, optical field to reliably control an atom. Using a new kind of geometry developed by Jaffe’s group, the technique would involve splitting, redirecting and recombining the atom in the cavity through a process called atom interferometry. Because atoms have mass and are acted upon by gravity, the process is useful for measuring gravity, Jaffe said.
“The quantum computing project dipped our toe into more complex optical cavity design to get new and useful performance – in this case, stronger interactions between an atom and a photon,” Jaffe said. “Once we opened that door, we realized there are all kinds of degrees of freedom we can explore for designing these cavities to get new types of light-matter interactions, so new ways of interfacing atoms and photons.”
He said the potential, strategic applications of manipulating light and matter to enable entanglement distribution include enhanced decryption capabilities and potential developments in chemistry, materials and biological molecules where quantum effects play a role.
Jaffe was drawn to AMO, which stands for the atomic-molecular-optical branch of physics, because of the field’s built-in balance between practicality and complex science.
“You have to have the technology and the sophistication there where you need it, but it also just has to work,” he said. “Hopefully the end product is a new, weird cavity talking to atoms in a new, weird way.”