China unveils first-of-its-kind 'dual-core' quantum computer — its makers say it improves stability and efficiency

A Chinese company has unveiled what its researchers are calling the world’s first "dual-core" quantum computer. It's a neutral-atom system designed to improve stability, efficiency and error correction by pairing two independent qubit arrays in a single machine.

The device, called "Hanyuan-2," is being promoted as a step toward more scalable quantum hardware. The Wuhan-based company CAS Cold Atom Technology announced the new machine in May, according to reports by ST Daily, a Chinese state media outlet, with technical details published on its website.

Gui-Guo Ge, a senior solutions expert at CAS Cold Atom Technology, the company behind the dual-core computer, told ST Daily that the system is built on independently controllable neutral-atom array technology. It works by conjoining two quantum arrays comprising a total of 200 qubits made from rubidium atoms (100 rubidium-87 atoms and 100 rubidium-85 atoms).

Ge added that the two cores are both complete arrays that can operate in parallel to boost computational efficiency or work in a "one main core and one auxiliary core" configuration to create more stable logical bits. That design is intended to address long-standing technical bottlenecks in single-core systems, including limited expansion and interference between neighboring qubits.

The dual-core architecture matters because quantum computers are notoriously fragile. Qubits are prone to "noise" in the form of small disturbances such as temperature fluctuations or electromagnetic interference, which can disrupt calculations. By splitting the system into two cooperating cores, Hanyuan-2 aims to reduce those problems by allowing the cores to correct each other's errors and divide tasks between them.

The setup offers a modular path to scaling up quantum processing units (QPUs), and the use of neutral atoms affords several advantages. For one, neutral atoms don't require massive dilution refrigerators that cool components to near absolute zero to function the way superconducting quantum computers, like those in use at IBM or Google machines do, meaning lower energy requirements.

Because neutral atoms are electrically neutral, they interact less with their environment than many other types of qubits, meaning qubits can, in theory, preserve quantum information for longer, with less decoherence — when calculations fail due to the collapse of superposition — and potentially improved error rates, providing longer coherence times.

Hanyuan-2 includes more than 500 optical tweezers arrays and a qubit lifetime of 100 seconds, according to the report. It also uses a standard rack-mounted design and needs only a small laser-cooling setup with power consumption below 7 kilowatts. This means it can be deployed in ordinary environments rather than specialized cryogenic facilities.

In context

In context

Keumars Afifi-Sabet

The announcement leaves many questions unanswered. For one, it's unclear if qubits can be entangled between the two separate "cores" — that is, achieving coherence in qubits between the rubidium-87 array and the rubidium-85 array or within the same cores. It's an important distinction, as two independent 100-qubit arrays aren't capable of solving problems that a single 200-qubit array could.

There's also no mention in the state media press release of benchmarks, including key metrics like coherence time or error rates. How this system compares with neutral-atom quantum computers built by scientists in the U.S. or Europe is unknown. A qubit lifetime of 100 seconds is also practically unheard of — with some notable exceptions.

The announcement is a tantalizing first step and seemingly a first of its kind. However, until the researchers fill in some of these blanks, the true significance of the "dual-core" system in minimizing errors and achieving "below threshold" noise suppression will remain murky.

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