Researchers around the world are racing to develop new quantum-based systems for sensing, communication, computing and control that have the promise of outperforming traditional systems. Creating stable, measurable, distinguishable quantum states—which would be the heart of any such system—is a daunting task.

Quantum states possess unique properties that can be exploited to develop novel information-processing systems. Two key properties, stability and distinguishability, are hard to achieve, however. Extracting information from a quantum system depends on the distinguishability of quantum states, an intrinsic property associated with a property known as orthogonality. Nevertheless, no two Gaussian states (a widely studied class of quantum states) are orthogonal, and this yields an unavoidable error when attempting to distinguish them.

In addition, present quantum devices tend to remain stable only for a fraction of a second and require complex protocols to distinguish states. Now, researchers at MIT and the University of Ferrara have found a new approach for creating easily distinguishable states that could help enable the development of these new quantum-based devices.

A team of U.S. researchers has designed a passive quantum error correction technique that enables qubits to correct their own errors. Demonstrated by Shruti Shirol and colleagues at the University of Massachusetts Amherst, the protocol transforms the inevitable dissipation of energy in qubit systems from a hindrance into an advantage, offering a promising route toward practical quantum computing outside the lab. The research has been published in Physical Review X.

As the building blocks of quantum computers, qubits aren’t limited to being either a 0 or a 1, like the classical bits that computers use today. Instead, they can exist in quantum superpositions of these states, offering new ways of storing and processing information.

However, these states are notoriously fragile. As they interact with vibrations and impurities in their surroundings, they can easily be destroyed, resulting in energy being dissipated from the system. To date, this poses one of the biggest roadblocks to building quantum computers in realistic settings outside the lab.