Quantum computing has long promised to revolutionise technology, but a key obstacle has kept it from reaching its full potential: qubits, the fundamental units of quantum information, lose their data too quickly.
Now, engineers at Princeton have built a quantum chip with a qubit that lasts three times longer than any previous laboratory record.
This breakthrough dramatically improves the stability of quantum processors and brings practical, large-scale quantum computing one step closer to reality.
The challenge of building practical quantum computers
Quantum computers promise to solve problems that are currently impossible for conventional computers.
Yet, the technology remains in its early stages. One major limitation is the fleeting lifespan of qubits. Current systems often see qubits lose coherence – essentially their stored information – before completing meaningful calculations.
Extending the qubit’s coherence time is critical for performing complex operations, reducing errors, and scaling up quantum processors.
Princeton’s latest achievement represents the most significant leap in qubit lifetime in over a decade, raising hopes for more reliable and scalable quantum machines.
A record-setting quantum chip
The Princeton team reported that their qubit maintains coherence for over 1 millisecond – three times longer than previous laboratory records and nearly 15 times longer than the standard in commercial processors.
To demonstrate its potential, the engineers built a fully functional quantum chip incorporating the new qubit, proving that it could handle real-world operations and clearing a key hurdle for industrial-scale quantum computing.
The design of the new qubit is compatible with existing architectures used by leading tech companies.
Experts suggest that integrating Princeton’s qubits into processors like Google’s Willow could dramatically enhance performance, potentially improving computational reliability by a factor of 1,000.
The benefits scale exponentially as more qubits are added, underscoring the design’s long-term potential.
The tantalum advantage
The Princeton team employed a two-pronged materials strategy to extend qubit lifetime.
First, they used tantalum, a metal that is exceptionally robust and less prone to surface defects that trap energy. These defects, common in metals like aluminium, are a major source of qubit errors.
By minimising them, tantalum enables qubits to preserve energy more efficiently, significantly extending coherence times.
The second key innovation was replacing the standard sapphire substrate with high-purity silicon, the backbone of modern computing. Silicon’s uniformity and availability make it ideal for scaling quantum chips to industrial levels.
Growing tantalum directly on silicon required overcoming technical challenges related to their distinct material properties, but the team succeeded, unlocking unprecedented qubit performance.
A major leap in transmon qubit technology
The qubit design builds on the transmon architecture, a superconducting circuit widely used by companies such as Google and IBM.
Transmon qubits operate at near absolute-zero temperatures and are relatively resistant to outside interference, but improving their coherence time has historically proven difficult.
By combining tantalum and silicon, the Princeton team achieved one of the largest single improvements in transmon performance in more than a decade.
This approach not only extends qubit lifespan but also prepares the design for larger, industrial-scale quantum chips.
The resulting enhancements scale exponentially: a hypothetical 1,000-qubit processor using Princeton’s design could operate roughly a billion times more effectively than current systems.
Implications for the future of quantum computing
This breakthrough represents more than just a lab record. By improving the durability of individual qubits, Princeton’s quantum chip addresses two critical challenges in quantum computing: error correction and scalability.
Longer-lived qubits reduce operational errors, making it feasible to assemble larger arrays of qubits without exponentially compounding mistakes.
Moreover, the use of silicon as a substrate positions the technology for industrial adoption. Silicon’s widespread availability and compatibility with conventional electronics manufacturing could help bridge the gap between laboratory prototypes and commercially viable quantum systems.
With these advancements, quantum computers may finally move closer to solving real-world problems that remain out of reach for classical machines – from cryptography and drug discovery to complex simulations in physics and finance.
Princeton’s quantum chip demonstrates that breakthroughs in hardware can directly translate into practical computational power, moving the field one step closer to functional, large-scale quantum computing.
