Researchers in Japan have launched "Shunkai," a quantum computer built using neutral atoms, which they hope to scale up to 10,000 qubits by March 2031. Named after a 17th-century astronomer, Shunkai is Japan's first full-stack quantum computer, meaning it includes all the necessary components—software, control systems, and hardware—to perform tasks similar to a traditional computer. This makes it potentially more accessible for researchers, with plans to open it to external users in the future. The project, led by Professor Kenji Ohmori, aims to use Shunkai to drive advancements in various sectors, from industry to government, by enabling more practical applications of quantum computing. Quantum computers rely on quantum physics, a field that governs the behavior of particles at the smallest scales. Unlike classical computers, which use bits that are either 0 or 1, quantum computers use qubits, which can represent both states simultaneously—a phenomenon known as superposition. However, qubits are highly sensitive to their environment, and even slight disturbances can cause errors. This makes quantum computing a complex challenge, as the error rate in qubits is significantly higher than in traditional computing. Researchers are working on quantum error correction to improve reliability, aiming to create more accurate qubits and scale up the number of qubits in a system. Shunkai stands out by using neutral atoms as qubits instead of the supercooled circuits common in many quantum systems. These atoms are captured and arranged using optical tweezers—highly focused laser beams that hold atoms in place within a vacuum. Microwaves or lasers then manipulate the atoms to perform calculations, and the results are read by observing the light emitted by each atom. This approach allows Shunkai to operate at room temperature, avoiding the need for complex cooling systems. Additionally, the flexibility of arranging qubits in neutral-atom systems allows researchers to control interactions and entanglement—where particles share information over distances—potentially overcoming challenges in scaling and error correction. The team behind Shunkai plans to integrate it into a shared supercomputing facility, creating a hybrid quantum-GPU computing center. Initially, the system will operate with around 50 qubits, expanding to 500 over time. The ultimate goal is to build a fault-tolerant quantum computer with 10,000 physical qubits by 2031, surpassing recent advancements by other research groups. Ohmori emphasized the significance of Shunkai as Japan's first full-stack quantum computer using this emerging technology, marking a major step in the global race to develop practical quantum systems.