Researchers are advancing several alternative qubit technologies for quantum computers, with two new papers on quantum dots and a separate processor using diamond defects highlighting the ongoing competition to find hardware that can scale reliably. While some quantum computing approaches already support thousands of qubits, companies pursuing these newer methods argue their techniques, though currently limited to small numbers of qubits, offer better long-term scalability because they can be manufactured using existing chip-fabrication processes.

HRL Laboratories, a descendant of Howard Hughes's original research programme, published work in Nature describing manufactured quantum dots that trap single electrons in silicon, using electron spin as the qubit. Unlike typical spin-qubit systems that rely on microwave controls, HRL's design uses three interacting quantum dots controlled purely through electronics, removing the need for microwave cabling into the refrigeration system. Its control chip operates at an intermediate cooling stage, consumes under 3.5 watts and is built on a 130nm process; the approach was compelling enough that IBM has acquired the company behind a related quantum dot technique, while a separate firm has also demonstrated a 100-qubit processor using electron defects in diamond.