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In the field of physics, scientists have long been puzzled by dark matter. Though it is five times more abundant throughout our universe than the ordinary matter that make up all we can see, dark matter rarely interacts with ordinary matter, making its detection a challenge.

Thanks to a three-year, $750,000 grant from the United States Department of Energy, ������̳ Assistant Professor of Physics Rakshya Khatiwada is working to build a highly sensitive dark matter detector utilizing the unique properties of crystalline sapphire.

Khatiwada’s grant is part of the Department of Energy’s for Quantum Information Science Enabled Discoveries for High Energy Physics.

The competitive peer review process saw —both from national labs-led larger collaborations and university-led, single principal investigator proposals—that employed quantum information science to enable new discoveries in fundamental physics.

In the past, dark matter searches mostly focused on detecting the ultra-rare interactions with ordinary matter. When a dark matter particle collides with a piece of ordinary matter, a flash of light or lattice vibrations is produced via nuclear or electronic excitations.

“For those excitations to occur, it typically requires much higher energy than just lattice vibrations in the atom,” Khatiwada explains.

Khatiwada’s project will instead use a sapphire crystal that is part of a qubit (quantum bit, the building block of quantum computers) to sense the tiny lattice vibrations when a dark matter particle interacts with the qubit. Composed of a repeating, symmetrical pattern of atoms, these crystal lattice structures can absorb energy and produce vibrations corresponding to the tiny signals from dark matter. The qubit performance can become worse when these lattice vibrations occur within the crystalline sapphire. By observing the qubit performance, Khatiwada aims to understand how sensitive of a detector can be built with qubits.

Khatiwada’s new detector may also have broader implications for quantum computing in general.

“Quantum computers have the same architecture as the particle detector that I’m trying to build. They are both based on superconducting qubits,” says Khatiwada. “Generally speaking, quantum computers have to worry about unwanted background particles and radiation that already exist in our atmosphere and the local qubit environment. These background noises can produce lattice vibrations in a qubit, which can degrade a quantum computer’s performance.”

By providing new insight into how the qubit couples to its environmental noise, Khatiwada hopes her project can provide strategies to mitigate this noise as well. Her research group at ������̳ and Fermilab has already been working toward a simulation of various qubit designs and measurement protocols and their effectiveness in sensing lattice vibrations.

This potential impact on both particle physics and quantum computing is what has Khatiwada most excited.

“The idea of sapphire being able to produce lattice vibrations with dark matter has been around for a few years, but nobody has really been able to definitively say how practical it is and what the challenges are in realizing such an idea, especially with a qubit hardware,” says Khatiwada. “Now I get to really explore how far we can go. It’s really exciting to see how other people think this specific idea that I came up with has a potential too.”