Quantum computing has long been lauded as the future of computing, perhaps as the future of technology. That said, engineering a quantum computer that functions under normal useable conditions is no easy task for researchers.
One of the biggest hurdles that quantum computing researchers have had to work on addressing is handling the temperature that these devices must work at. Historically, quantum computers have only worked at extremely low lab-grade temperatures. At around -460 degrees Fahrenheit, quantum computers find their optimal working temperature. As one might be able to guess, that's not an easily achievable temperature for just any room.
All that said, researchers have just discovered a new way that allows quantum computers to function at room temperature. This could severely decrease costs and decrease the barrier to entry into creating a quantum device.
Creating a quantum computer that works under standard thermal conditions puts researchers one step closer to scaling quantum computing to a variety of mass-appeal uses.
Understanding what the researchers discovered
Most qubits, which are the quantum particles central to the function of quantum computers, only operate on superconducting materials. Superconductors work best at extremely low temperatures. In order to get around this, the researchers looked into using defects in silicon carbide to hold the qubits in their respective places instead. This is not only simpler, but it makes the machines far more cost-effective as well.
Silicon carbide, or SiC, is not new to the quantum computing world. It's been explored as a potential holder of qubits for quantum computers for some time now. However, it wasn't until researchers from the Linköping University in Sweden discovered that the could slightly modify the structural properties of silicon carbide to make it hold the qubits perfectly.
In their paper published in Nature, the have this to say about their groundbreaking research.
"We identify a pathway around these drawbacks by showing that an engineered quantum well can stabilize the charge state of a qubit. Using density-functional theory and experimental synchrotron X-ray diffraction studies, we construct a model for previously unattributed point defect centers in silicon carbide as a near-stacking fault axial divacancy and show how this model explains these defects’ robustness against photoionization and room temperature stability."
Essentially, the researchers are making atom-level modifications to the silicon carbide to ensure that they are able to hold the qubits in place. They're making atom-sized defects in the material in which they can hold a qubit.
Igor Abrikosov, Professor, scientific advisor of Materials Modeling and Development laboratory at NUST MISIS, Head of Theoretical Physics Division at the Department of Physics, Chemistry and Biology, Linköping University, explained it this way:
“To create a qubit, a point defect in a crystal lattice is being excited using laser, and when a photon is emitted, this defect begins to luminesce. It was previously proved that six peaks are observed in the luminescence of SiC, named from PL1 to PL6, respectively. We found out that this is due to a specific defect, where a single ‘displaced’ atomic layer, called a stacking fault, appears near two vacant positions in the lattice”
In 2019, researchers also experimented with the atom-level type modifications, but in the previous instance, they were working with diamonds. The benefit of using silicon carbide is that it's significantly cheaper than utilizing diamond.
Researchers at @yokohama_saigai have created and manipulated geometric spin qubits in diamond NV centers at room temperature and zero magnetic field. They demonstrate long lived quantum memories through universal holonomic gates for quantum repeaters.https://t.co/jB14QE3TZq— Austin Bradley (@AustinToMars) August 13, 2018
In theory, all of this should work, but like many things in the quantum world, actually testing the researchers' theories is harder than you might think.
What stands ahead for the researchers
The concepts and mathematics behind utilizing silicon carbide for holding qubits at room temperature all check out, but the researchers have a number of practical hurdles still standing in their way.
They have to develop a process that will allow them to strategically place the defects in the SiC exactly where they need them. The research team has to essentially develop their own processes to do this, which will take some time, according to the team.
At the end of the day, the discoveries made by the team at Linköping University are still in their early stages of demonstrating practical efficacy. It all looks promising though, and soon, quantum scientists might have a far easier way to develop the core structure of quantum computers.