IBM is making bold strides in the race to build practical quantum computers, taking a unique path compared to its rivals like Google. The company recently unveiled two groundbreaking quantum computers, Nighthawk and Loon, designed to overcome major limitations of existing quantum technology.
These new systems represent a significant shift towards modularity. Unlike competitors who focus on building ever-larger single units, IBM is assembling quantum computers from interconnected modules. This approach hinges on the ability to efficiently connect superconducting qubits – the fundamental building blocks of quantum computation – both within and between these modules. Initially, some experts doubted the practicality of such complex interconnections. Now, IBM aims to prove them wrong.
Loon stands out with its revolutionary “breaking the plane” connectivity. Each qubit within Loon is linked to six others, allowing connections to extend not just horizontally across a chip but also vertically – a feat unmatched in any other superconducting quantum computer. Nighthawk, on the other hand, boasts four-way qubit connectivity.
This enhanced connectivity holds immense potential for tackling two major hurdles facing current quantum computers: limited computational power and inherent error rates. Preliminary tests on Nighthawk indicate it can handle computations 30% more complex than IBM’s most widely used quantum computer. This increased complexity could unlock a wider range of applications for quantum computing, building on the initial progress in fields like chemistry.
IBM also champions a unique method to create “logical qubits” – groups of physical qubits that function as single, error-free units. Unlike competitors who use larger groups, IBM’s approach relies on smaller ones. This strategy could enable practical error-free computation without requiring millions of individual qubits – a significant cost and engineering challenge. However, it hinges on the very connectivity that Nighthawk and Loon demonstrate.
Stephen Bartlett, a quantum computing expert at the University of Sydney, acknowledges the need for further testing but hails the increased qubit connectivity as “a significant major step” towards building truly powerful quantum computers. While still in its early stages, this modular approach represents a promising direction for scaling up quantum technology.
IBM faces several engineering and physics challenges ahead. These include optimizing the readout of computation results and extending the coherence time – the duration qubits maintain their delicate quantum state – which can be affected by increased connections. The company is also exploring techniques to reset specific qubits during calculations.
Looking forward, IBM plans to launch a fully modular quantum computer in 2026, capable of both storing and processing information. This ambitious project will be informed by the insights gleaned from ongoing testing and development of Nighthawk and Loon.
