Reducing noise with qubit virtualization
Today’s qubits are inherently noisy. Noise must be addressed to make today’s qubits useful. Microsoft’s qubit-virtualization system dramatically reduces the effects of noise and enables the world’s most reliable logical qubits.
Quality is more important than quantity...
...especially when it comes to qubits
Having a lot of noisy qubits together can just make a quantum system more noisy, and of limited use. Some of today’s qubits that have high enough fidelities and other critical-to-quality properties, when combined with Microsoft’s qubit-virtualization system, can become highly reliable logical qubits and graduate to Level 2 Resilient quantum computing.
Noise is inherent to quantum computing
A half century ago, in the early days of classical computing, scientists and researchers had to give serious consideration to errors in classical machines. Today, we don’t think about errors when using our smartphones and other devices. Why? Compute and memory errors are essentially zero in the classical realm, because errors are easily mitigated. This is not the case with quantum computing—where noise and resulting errors are inherent to even the highest quality qubits. Active error diagnostics and corrections are required to make noisy qubits reliable.
Creating reliable logical qubits from noisy physical qubits
One or more qubits can be encoded among several physical qubits and operated carefully in concert. This creates what is commonly referred to as a logical qubit, or a virtual qubit because it exists only as a pool of physical qubits, and no longer as a single, physical qubit. Not all logical qubits have the same degree of usefulness. Logical qubit error rates must be below physical qubit error rates to be reliable, and thus useful.
Microsoft and Quantinuum achieve reliable quantum computing
Using Microsoft's qubit virtualization and Quantinuum's H2 hardware, Microsoft and Quantinuum have demonstrated the world’s most reliable logical qubits, with 800-times better error rate compared to physical qubits. For comparison, that’s roughly the same as a 29 dB signal improvement, which is what noise-canceling headphones provide. Think of the environmental noise on an airplane being akin to the noise level that today’s physical qubits exhibit. By switching on noise cancelation (or using Microsoft’s qubit virtualization) you remove most of that environmental noise and can now listen to music clearly (akin to highly reliable logical qubits).
Paving a clear path to applications
Engineering reliable logical qubits is a critical technology milestone toward accelerating scientific discovery. Exiting the NISQ era and entering the era of reliable quantum computing provides a clear path toward solving chemistry and materials science problems with Azure Quantum Elements, and onward to scale.