Breakthrough in quantum sensing by Northeastern University researchers provides new material to make qubits

(Phys.org) Atomic defects in certain solid crystals may be key to unleashing the potential of the quantum revolution, according to new discoveries by researchers at Northeastern University. The defects are essentially irregularities in the way that atoms are arranged to form crystalline structures. Those irregularities could provide the physical conditions to host something called a quantum bit, or qubit for short—a foundational building block for quantum technologies, says Arun Bansil, university distinguished professor in the Department of Physics at Northeastern.
Bansil and colleagues found that defects in a certain class of materials, specifically two-dimensional transition metal dichalcogenides, contained the atomic properties conducive to make qubits. Bansil says the findings, which are described in a study published in Nature Communications, amount to something of a breakthrough, particularly in quantum sensing, and may help accelerate the pace of technological change.
“If we can learn how to create qubits in this two-dimensional matrix, that is a big, big deal,” Bansil says.
Using advanced computations, Bansil and his colleagues sifted through hundreds of different material combinations to find those capable of hosting a qubit.
The key finding of the study is that the so-called “antisite” defect in films of the two-dimensional transition metal dichalcogenides carries something called “spin” with it. Spin, also called angular momentum, describes a fundamental property of electrons defined in one of two potential states: up or down, Bansil says.
The challenge for researchers has been how to find qubits that are stable enough to use, given the difficulties in finding the precise atomic conditions under which they can be materially realized.
“The current qubits available—especially those involved in quantum computing—all operate at very low temperatures, making them incredibly fragile,” Bansil says. That’s why the discovery of transition metal dichalcogenides’ defects holds such promise, he adds.