Error-corrected operations run 1,000 times faster, advancing quantum computing

Quantum computers have long promised to transform science and technology, from accelerating drug discovery to redesigning energy systems and cracking problems in cryptography, artificial intelligence and logistics that no classical machine could ever hope to solve. Yet that promise has always come with a stubborn caveat: quantum computers are extraordinarily fragile. Their fundamental units of information, qubits, are so sensitive to their surroundings that even the faintest electrical noise, a stray cosmic ray, or a slight overheating event can scramble a computation before it has barely begun. Now, researchers at Chalmers University of Technology in Sweden have unveiled a method that allows a broad class of advanced quantum operations to be carried out more than a thousand times faster than previously possible, a leap that directly targets one of the most persistent bottlenecks standing between today’s error-prone machines and the fault-tolerant quantum computers of the future.

The essence of the problem lies in the physics of quantum information itself. Unlike the bits of a conventional computer, which sit comfortably in well-defined states of zero or one, qubits exist in delicate superpositions that can be destroyed by virtually any interaction with the environment. Conventional computers also suffer from errors caused by noise and radiation, but decades of mature error-correction techniques allow those errors to be detected and repaired almost instantly. In the quantum realm, however, the rules are far harsher. If too many errors accumulate before they can be corrected, the entire computation collapses into meaningless noise. The longer any quantum operation takes, the larger the window of vulnerability, which is precisely why speed is not merely a convenience in quantum computing but a fundamental requirement for reliability.

Lei Du, a researcher in Applied Quantum Physics at Chalmers and lead author of the new theoretical study published in Physical Review Letters, explains the stakes plainly. “The fundamental building blocks of quantum computers, known as qubits, are so sensitive that even the smallest disturbance can cause the quantum state to deviate from the target, resulting in the loss of information. If too many errors accumulate before they can be corrected, the computation can fail,” Du says. In other words, every millisecond that a quantum system spends exposed to its environment is a millisecond in which the information it holds risks decaying beyond repair. Cutting the duration of quantum operations by three orders of magnitude therefore does far more than make calculations quicker; it fundamentally changes the error budget within which a working quantum computer must operate.

To confront this fragility, the field has been exploring more resilient ways of storing quantum information. One of the most promising strategies involves bosonic quantum codes, an approach that departs from the idea of encoding information in individual qubits. Instead, bosonic codes distribute quantum information across the microwave fields contained within superconducting circuits, using the rich structure of these electromagnetic oscillations as a protective container. As Tangyou Huang, a researcher in Quantum Technology at Chalmers and co-author of the study, notes, “Rather than storing quantum information in individual qubits, bosonic codes encode information in the microwave fields found within superconducting circuits. This approach has been shown to provide stronger protection against certain types of errors.” In essence, bosonic codes build a measure of error resistance directly into the hardware, providing an intrinsic shield that individual qubits alone cannot offer.

But there has always been a catch. While bosonic codes are excellent at protecting information, the quantum operations needed to create and manipulate these encoded states are notoriously difficult to perform. Previous techniques built up the required quantum states piece by piece, guiding the system through thousands of repeated driving cycles in a slow, painstaking process. Each additional cycle adds another opportunity for environmental disturbances to corrupt the delicate states being assembled. The irony was sharp: the very error-correcting structures designed to protect quantum information had to be constructed through procedures so slow and cumbersome that errors could creep in before the protection was even in place. This paradox has long been recognized as a key obstacle on the road to practical fault-tolerant quantum computing.

The Chalmers team’s breakthrough lies in abandoning the step-by-step construction paradigm altogether. Rather than assembling quantum states incrementally, Du and Huang devised a method that can complete a diverse range of quantum operations on bosonic states within a single driving cycle of the system, rather than the several thousand cycles previously required. “Our method shows that a diverse range of quantum operations on bosonic states can be completed within a single driving cycle, rather than the several thousand cycles that have been required previously. This makes the operations both faster and more efficient, while reducing the risk that disturbances will corrupt the information before the process is finished. It represents an important step towards fault-tolerant quantum computers,” Du says. By compressing operations that once spanned thousands of periods into a single period, the technique reduces the exposure time of fragile quantum information by a factor of more than a thousand, dramatically shrinking the probability that noise will strike mid-operation.

The theoretical engine behind this speed-up is a newly proposed class of operations known as quantum lattice gates, first introduced by the same research team in earlier work. These gates form a universal set of elementary building blocks for controlling bosonic quantum states, functioning much like shortcut commands that allow complex operations to be executed in one stroke rather than through long sequences of elementary steps. Huang offers a vivid analogy: “You can think of it like building a large Lego castle. Instead of assembling it brick by brick and risking mistakes along the way, quantum lattice gates act like pre-built Lego modules that can be connected quickly and efficiently.” The image captures the conceptual shift precisely: where previous approaches stacked up thousands of small, error-prone interventions, the new framework provides robust, prefabricated units that snap together with minimal overhead.

Underneath this framework lies a control technique known as Floquet control, in which a quantum system is driven by carefully designed periodic control signals. Floquet engineering has become a powerful tool in modern quantum physics, allowing researchers to sculpt the effective dynamics of a quantum system by shaping how it is periodically driven. Previous Floquet-based implementations of bosonic operations, however, relied on slow processes that demanded many driving cycles to converge. The new method achieves what earlier schemes could not: it implements quantum lattice gates directly within a single driving period, exploiting the fine structure of the system’s driven dynamics so that the desired transformation occurs essentially immediately. The result, documented in the paper “Single-Period Floquet Control of Bosonic Codes with Quantum Lattice Gates,” is a control paradigm in which some operations become more than a thousand times faster than their predecessors.

Crucially, the method is not confined to an abstract theory. It is tailored for superconducting quantum computers, one of the leading hardware platforms in the global race toward large-scale quantum machines, and the same technology being pursued at Chalmers itself, where a 100-qubit quantum computer is currently under development. “A key advantage of our approach is that it can be implemented using existing superconducting quantum circuit platforms. We are already discussing possible experimental realisations with colleagues at Chalmers, and we hope to see a demonstration of the method in the near future,” Huang says. Because the technique builds on hardware architectures that already exist in laboratories around the world, the path from theory to experiment may be considerably shorter than for approaches that would require entirely new physical platforms. An experimental demonstration would mark a decisive step in validating whether the dramatic theoretical speed-up survives contact with the imperfections of real devices.

For the field at large, the significance of the work goes beyond a single impressive number. The creation and manipulation of error-correcting quantum states, such as those encoded in bosonic codes, is widely regarded as one of the major unsolved engineering challenges in quantum computing. Every fault-tolerant architecture ultimately depends on being able to prepare, control and measure protected quantum states quickly and reliably, faster than errors can accumulate. By showing that such operations can, in principle, be executed within a single driving cycle on standard superconducting hardware, the Chalmers researchers have demonstrated that the speed barrier was not an unavoidable feature of quantum physics but a limitation of control strategies, one that clever theoretical design can shatter. “Our results address one of the major bottlenecks in the field: how to quickly and reliably create and control the error-correcting quantum states that could play an important role in future quantum computers,” Du says.

The study, authored by Tangyou Huang, Lei Du and Lingzhen Guo, was conducted by researchers affiliated with Chalmers University of Technology in Sweden and Tianjin University in China, and was funded by the National Natural Science Foundation of China, the Wallenberg Centre for Quantum Technology, and the Knut and Alice Wallenberg Foundation. As quantum computers worldwide continue to grow in size and ambition, techniques like single-period Floquet control may prove essential in converting raw hardware into machines that can actually deliver on the field’s long-standing promises. If the coming experimental demonstrations succeed, the thousand-fold acceleration could be remembered as one of the pivotal steps that carried quantum computing out of its fragile infancy and into the era of genuine fault tolerance.

News Publication Date: 10-Sep-2026

Web References: https://doi.org/10.1103/tnb8-3m8m; https://www.nature.com/articles/s42005-025-02354-0

References: Huang, T., Du, L., & Guo, L. (2026). Single-period Floquet control of bosonic codes with quantum lattice gates. Physical Review Letters. https://doi.org/10.1103/tnb8-3m8m