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"3D" superconducting qubit device
Scientists at IBM say they have made a quantum computing breakthrough that demonstrates that a full-scale quantum computer is not only possible, but is within reasonable reach.
On Tuesday, IBM's researchers are expected to report that they have achieved three records for error correction in elementary calculations with quantum computers.
Quantum computing relies on the contents of quantum bits — qubits, or qbits — existing in many different states at once, with the correct answer to a question coming from the way multiple qubits interact while in multiple states. If a qubit interacts with its surroundings in a non-reversible way — a process called decoherence — the quantum calculation stops, and thus effective quantum computing relies on maintaining coherence for long enough to be useful. Moreover, quantum computing is a statistical process and reliant on error detection and correction for accuracy.
In tests with a two-dimensional qubit device, IBM's team had a 95-percent success rate in carrying out a two-qubit logic operation. While doing this, they managed to maintain coherence for almost 10 microseconds. "These numbers are on the cusp of effective error-correction schemes and greatly facilitate future multi-qubit experiments," IBM said in a statement.
In addition, the researchers carried out experiments with a 3D supercomputing qubit, in which the qubit maintained its quantum state up to 100 microseconds. "This value reaches just past the minimum threshold to enable effective error correction schemes and suggests that scientists can begin to focus on broader engineering aspects for scalability," IBM said.
Qubits could allow a quantum computer to perform millions of computations at a time, IBM said, and a single 250-qubit state would have more information bits than there are particles in the universe.
"The quantum computing work we are doing shows it is no longer just a brute force physics experiment. It's time to start creating systems based on this science that will take computing to a new frontier," Matthias Steffen, manager of IBM's experimental quantum computing group, said in the statement.
IBM's scientists will give details of their experiments on Tuesday at the annual meeting of the American Physical Society in Boston.
Pictured above is a "3D" superconducting qubit device "where a qubit (about 1mm in length) is suspended in the center of the cavity on a small sapphire chip. The cavity is formed by closing the two halves, and measurements are done by passing microwave signals to the connectors", according to IBM. Although the cavity here is about an inch-and-a-half wide, IBM thinks it can scale this kind of system to hundreds or even thousands of qubits.
Image credit: IBM Research