Quantum computers, which operate leveraging quantum mechanics phenomena, could eventually tackle some optimization and computational problems faster and more efficiently than their classical counterparts. Instead of bits, the fundamental units of information in classical computers, quantum computers rely on qubits (quantum bits), which can be in multiple states at once.

Silicon-based quantum dots, semiconductor-based structures that trap individual electrons, have been widely used as qubits, as the spin state of the electrons they confine can be leveraged to encode information. Despite their promise, many quantum computers developed so far are susceptible to decoherence, which entails the disruption of qubit states due to their interaction with the surrounding environment.

Researchers at the University of Rochester recently set out to experimentally realize a so-called nuclear-spin dark state, a condition that has been theorized to improve the performance of quantum computers, suppressing undesirable interactions and thus reducing decoherence. Their paper, published in Nature Physics, demonstrates the potential of this state for reducing decoherence in quantum systems and thus potentially improving control over quantum information processing.

In a leap forward for quantum computing, a Microsoft team led by UC Santa Barbara physicists on Wednesday unveiled an eight-qubit topological quantum processor, the first of its kind. The chip, built as a proof-of-concept for the scientists’ design, opens the door to the development of the long-awaited topological quantum computer.

“We’ve got a bunch of stuff that we’ve been keeping under wraps that we’re dropping all at once now,” said Microsoft Station Q Director Chetan Nayak, a professor of physics at UCSB and a Technical Fellow for Quantum Hardware at Microsoft. The chip was revealed at Station Q’s annual conference in Santa Barbara, and accompanies a paper published in the journal Nature, authored by Station Q, their Microsoft teammates and a host of collaborators that presents the research team’s measurements of these new qubits.

“We have created a new state of matter called a topological superconductor,” Nayak explained. This phase of matter hosts exotic boundaries called Majorana zero modes (MZM) that are useful for quantum computing, he explained. Results of rigorous simulation and testing of their heterostructure devices are consistent with the observation of such states. “It shows that we can do it, do it fast and do it accurately,” he said.