A groundbreaking achievement in the world of quantum computing has been made with the successful entanglement of a record-breaking 51 qubits within a quantum computer. Past attempts to reach this high level of entanglement had proven unsuccessful until now, marking a significant advancement in quantum computing capabilities.
When two quantum particles become entangled, alterations to one particle automatically initiate the corresponding changes in the other. This fascinating quantum phenomenon, however, extends beyond mere pairings. Given a sufficiently large number of particles, every particle can be entangled with all the others, exhibiting a much higher complexity.
Research dating back to the late 1980s has managed to entangle up to three or four light particles. More recently, entanglement of up to 27 qubits in a quantum computer has been reported. Yet, Xiao-bo Zhu and his team at the University of Science and Technology of China have now shattered this record, successfully entangling a whopping 51 qubits.
Their tool of choice was the Zuchongzhi quantum computer, renowned for its quantum supremacy, having previously solved highly complex problems faster than any existing supercomputer. The Zuchongzhi houses 66 superconducting qubits — minute loops of a superconducting material that transfers electricity without any loss. Zhu’s team manipulated the state of these qubits using microwaves and modulated their interactions through pulses of magnetic fields.
The team executed quantum logic gates, sequences of operations that alter the quantum states of the qubits, on numerous pairs of qubits simultaneously. As a result, they successfully entangled 51 qubits in a linear arrangement and 30 qubits in a two-dimensional plane setting, setting a new record in both instances.
Nathan Lacroix of the Swiss Federal Institute of Technology in Zurich praised the achievement, attributing it to meticulous calibration and thoughtful design choices. While acknowledging that similar systems housing up to 57 qubits have been created, Lacroix highlighted the unique accomplishment of Zhu’s team in verifying entanglement across all qubits.
“Entanglement is one of the key distinctions between conventional computers and quantum computers. It’s a vital element of quantum algorithms, making the demonstration of large numbers of entangled qubits an essential benchmark for quantum computing,” stated Charles Hill at the University of New South Wales in Australia.
Developing a novel method for witnessing entanglement was key to the accomplishment, Zhu explained. This involved a clever selection of a minimum set of measurements to sufficiently understand the qubits’ activities without overburdening time or computational resources.
Christian Andersen at Delft University of Technology in the Netherlands, although unsure of the immediate applications of 51 entangled qubits, commended the team’s impressive technical achievement. He added that the complexity of the system, having no parallel in classical physics, may inspire other researchers in their work with superconducting qubits.