Scientists from Qutech have reached a large milestone in Quantum computer By creating very precise quantums on a diamond chip that achieve error rates of only 0.001%.
By using diamonds and advanced gate designs with ultra-pure-pure-pure-gate, the team overcame the most important challenges that have limited earlier approaches. These precise gates carried out strict tests with long surgical sequences and mark a significant step towards building scalable quantum computers.
Why quantum computers need ultra -goals
Quantum computers are expected to tackle complex problems that go beyond the range of classic computers. In order to carry out calculations, they rely on sequences of basic processes that are referred to as quantum grilles. In order for a quantum computer to work reliably, these goals must be extremely accurate. The likelihood of an error that occurs during every gate operation must be very low, typically below 0.1 to 1 percent. Only with these low error rates can the quantum error correction techniques work effectively, which also enables precise calculation when using incomplete hardware.
Diamond rotations: a promising qubit platform
A promising type of qubit is based on spins in the diamond. These qubits use the electron and nuclear spins associated with atomic defects in the diamond grille, for example in the case of nitrogen atom Takes the place of a carbon atom. These defects offer several advantages: You can work at relatively high temperatures (up to 10 Kelvin), are well shielded from environmental noises and of course interact with photons, which makes them ideal for building quantum networks. Until recently, reaching a complete set of quantums with sufficiently low error rates using Diamond Spins remained a significant challenge.
Precise universal goals on diamond chips
Researchers from QUTECH, the interfaculty quantum technology research institute of Delft University of Technology, have now shown a very precise universal sentence of quantum gaters using a diamond quantum chip. The researchers used a system of two quBITs formed by the electron spin of the defect center, the other through its nuclear spin. Each type of gate in this two-qubit system works with an error below 0.1%and the best goals even achieve errors of up to 0.001%.
“In order to realize such precise gates, we had to systematically remove sources of error. The first step was to use ultra-like diamonds who have a lower concentration of carbon-13 isotopes if this causes noise,” says Hans Bartling, senior author. The second key step was to design goals that carefully decouple the spin -ups from each other and from interactions with the remaining noise in the area.
Characterization, optimization and testing of the quantums
One final challenge was to find tools to reliably characterize the gates and optimize their parameters. For this purpose, the team of a method called “Gate Set Tomography” turned to the full quantum description of the goals. “It was important that our characterization provided complete and precise information about the gate errors because we made it possible to systematically find imperfections and optimize all gate parameters,” says co-author Jiwon Yun.
Ultimately, the researchers put the quantums and their characterization on the test by performing an artificial algorithm with a large sequence of gates. After 800 gate operations, the result of the team's knowledge about the individual gates could be predicted exactly, which indicates that the Gate operations have now been understood both precisely and well.
Scaling: challenges on the way to full quantum performance
While high-precision universal gates are an important prerequisite for the quantum calculation, there is still a long way to calculate on a large scale. “Our demonstration was on a two-qubit system and used a certain type of defect,” says Tim Taminiau, who monitors research. “An important challenge is to maintain and further improve the quality of the gate if you switch to the integrated optics and electronics to chip standards and scale to many other quBITs.”
The realization of such larger processors is the focus of the research efforts at Qutech and the collaboration with Fujitsu. The team pursues a complete stack approach in which not only improved quantum bits are examined, but also the required control electronics, scalable manufacturing methods and new types of quantum computer architectures. “If you take the next big step, scientists, engineers and industry have to be brought together,” says Taminiau.
Reference: “Universal High Fidelity Quantum Gates for Spin-Qubits in Diamond” by HP Bartling, J. Yun, KN Schymik, M. van Riggelen, La Dehoven, HB Van Omen, M. Babaie, F. Sebastiano, M. Markham, DJ Twitch and TH Taminiau, March 21, 2025, 2025, 2025, 2025 2025, 2025, Physical review applied.
DOI: 10.1103/Physrevapplied.23.034052