Diamonds are among the most expensive gems in the world, but they could also serve as a building block for quantum computers.
Because diamonds are structurally sound, researchers believe they could eliminate some of the challenges involved in making stable quantum computers.
The potential of quantum computers is enormous — they could bring massive gains in computational power and ultimately replace today’s PCs and servers.
But universal quantum computers are still decades away, partly because of the complexity involved in building such systems. Quantum computers are considered notoriously unstable, but researchers working on ways to resolve existing material, programming, and hardware challenges.
Researchers at North Carolina State University have developed a system to synthetically make microscopic diamonds — also called nanodiamonds — in specialized crystalline structures to stabilize calculations in quantum computers.
The researchers tweaked the structure of a nanodiamond, which is made of carbon atoms, to stabilize the qubits at the center of quantum computers. The impure nanodiamond provides a way for the qubit to change states in a stable form.
Today’s computers store bits of data in the form of 1s and 0s, while quantum computers are driven by qubits, which can store a 1 and 0 simultaneously in multiplying states. Called superposition, the expansion of qubits can give explosive computing potential to quantum computers.
But qubits can be unstable and fragile, which is why quantum computers have been so elusive. The behavior and state of qubits can be hard to predict once they start interacting, or “entangling,” to perform a calculation. If qubits spin out of control, computational cycles can be wrecked.
The NCSU researchers established a new technique to create single-crystal nanodiamonds, which could potentially be components in quantum computers operating at room temperature. The technique also creates a stable environment for superposition, which helps carry out calculations reliably.
There are already quantum computers developed using techniques from IBM and D-Wave Systems, but they need to be cooled in refrigerators.
A pure diamond dug out from earth has carbon atoms meshed together. The research team has created an “NV-doped” (nitrogen vacancy doped) nanodiamond with one nitrogen atom in the center in the place of a carbon atom. The NV-doped center turns the nanodiamond into a qubit.
The NV center itself can remain stable in superposition because it can transition between states when an electric current or laser is applied to it.
The researchers created the NV-doped nanodiamond synthetically by coating a substrate with amorphous carbon in an undefined structure and then bombarding it with nitrogen ions and carbon-13 ions.
The operation takes place at around 4,000 Kelvin and takes a millionth of a second. The technique reduces impurities that could disrupt quantum computational cycles, the researchers said.
The new technique to create NV-doped nanodiamonds is inexpensive and will enable significant advances in quantum computing, said Jay Narayan, a professor at NCSU.
The researchers are talking to private and public organizations about how their research could be used to manufacture quantum computers.