Quantum computing's achilles' heel: Tech giants are tackling an error crisis

Hindustan Times

20-06-2025

At the turn of this year, the course became clear. First, quantum computing chips made a generational leap, albeit with Microsoft and Google taking different approaches to generating desired performance. Now, Microsoft has pushed the envelope further, having developed error-correction codes that are applicable to many types of qubits. So has IBM, signifying broad efforts towards the same result.
The company insists the present generation of quantum computers, that use qubits, often run into errors, which they cannot resolve on their own. 'Reliable quantum computing requires progress across the full stack, from error correction to hardware. With new 4D codes reducing error rates 1,000x, and our co-designed quantum system with Atom Computing, we're bringing utility-scale quantum closer than ever,' says Satya Nadella, Microsoft Chairman and CEO.
Atom Computing builds scalable quantum computers.
A quantum computer, compared with traditional, familiar computers, pack magnitudes more computing power to be able to solve complex problems. To compute, traditional computers store information in bits (that is, 0 and 1). Quantum computing is built around qubits that do both at the same time (a bit like Shrodinger's cat).
They are not designed to replace traditional computers, at least work and home uses. One could point to the 2024 movie AfrAId, and Netflix' 2023 movie Heart Of Stone, as having foretold quantum's prowess.
Microsoft's four-dimensional geometric codes require fewer physical qubits for compute, can check for errors faster, and have reportedly returned a 1,000-fold reduction in error rates. There is hope for this framework of error detection and correction, that can adapt to various types of qubits, making the technology more versatile and practical for real-world applications.
The significance of Microsoft's approach cannot be overstated. Traditional quantum error correction methods have struggled with a delicate balance between protecting quantum information whilst maintaining the very properties that make quantum computing powerful.
They aren't the only tech giant that is tackling errors in quantum computing.
IBM, this month, detailed a roadmap for the IBM Quantum Starling, which they say is the world's first large-scale fault-tolerant quantum computer. It is expected to be delivered by 2029, as part of IBM's new Quantum Data Center.
'Our expertise across mathematics, physics, and engineering is paving the way for a large-scale, fault-tolerant quantum computer — one that will solve real-world challenges and unlock immense possibilities for business,' says said Arvind Krishna, Chairman and CEO of IBM.
Quantum computing stands at a critical juncture. Qubits are extremely sensitive to their environment. Smallest of disturbances, ranging from electromagnetic interference to temperature fluctuations, can cause them to 'decohere'. That means, they lose their quantum properties and essentially become classical bits. At that stage, quantum computations produce errors.
The challenge is both technical and mathematical. Since quantum states cannot be copied like data on a computer, quantum error correction becomes exponentially more complex.
Microsoft is assessing this development with a sense of caution.
'We are in the early stages of reliable quantum computing, and the impact that this technology will have is just beginning to be realised. Practical applications will start to be revealed as researchers in various industries adopt a co-design approach to explore interactions between quantum architectures, algorithms, and applications,' explains Krysta Svore, Technical Fellow, Advanced Quantum Development at Microsoft Quantum.
Earlier in the year, Microsoft's quantum computing aspirations saw significant forward movement, with the Majorana 1 chip — a first of its kind scalable chip with versatile architecture, that can potentially fit a million qubits. It currently holds 8 topological qubits.
Majorana 1 sits alongside Google's Willow chip, IBM's Quantum Heron, as well as the Zuchongzhi 3.0, developed by Chinese scientists late last year. Error correction was a focus area then too. Microsoft created what is essentially a new state of matter called a topological superconductor, that is more stable and error resistant.
Google too believes it has cracked the code for error correction and is building a machine that they expect will be ready by 2029. Crucial to their approach is the Willow chip, and the balance between logical qubits and physical qubits.
Physical qubits are the actual quantum bits built into the hardware - the individual atoms, photons, or superconducting circuits that store quantum information. Whereas, logical qubits are error-corrected qubits created by combining multiple physical qubits together with sophisticated error correction codes. Think of them as 'virtual' qubits.
Google's research points to the 'quantum error correction threshold', as the tipping point where this dynamic reverses — where logical qubits that are more reliable, outnumber physical ones.
There are similarities in Google and IBM's approach regarding this balance.
Central to IBM's approach is its creation of a quantum error-correcting code that they claim is about 10 times more efficient than prior methods. This efficiency gain proves crucial, at least in tests, because traditional error correction methods require hundreds or thousands of physical qubits to create a single reliable logical qubit, making large-scale quantum computers prohibitively complex.
For all the potential that quantum computing may profess to, at least in delivering real-world solutions for matters including drug discovery, cybersecurity, material science and financial risk analysis, it finds itself precariously perched in this pivotal moment. Error correction capabilities are important for it to simply work as it should, and also to keep operational costs down.
IBM's modular scalability, Google's systematic threshold-crossing methodology, and Microsoft's new 4D code architecture, though differing in approach, all believe they may be rushing towards a workable solution. As quantum creeps ever closer, the years that lie ahead will testify to levels of success.