Doubling a qubit’s life, researchers prove a key theory of quantum physics

Amazing stuff! Could be a breakthrough! Extending classical error correction to quantum physics! Again machine learning was applied in this research!

"Researchers at Yale have for the first time, using a process known as quantum error correction, substantially extended the lifetime of a quantum bit — a long-sought-after goal and one of the trickiest challenges in the field of quantum physics. ...
decades after its theoretical foundations were proposed — that quantum error correction works in practice.  ...

Quantum systems, though, are fragile. They are bedeviled by a fundamental phenomenon of decoherence, a process in which the information stored in qubits quickly loses its quantum properties as a result of their interactions with the surrounding environment. 

Quantum error correction, which was theoretically discovered in 1995, offers a means to combat this decoherence. Employing redundancy, it protects the quantum bit of information by encoding it in a system larger than what, in principle, is needed to represent a single qubit. ..."

From the abstract:

"The ambition of harnessing the quantum for computation is at odds with the fundamental phenomenon of decoherence. The purpose of quantum error correction (QEC) is to counteract the natural tendency of a complex system to decohere. This cooperative process, which requires participation of multiple quantum and classical components, creates a special type of dissipation that removes the entropy caused by the errors faster than the rate at which these errors corrupt the stored quantum information. Previous experimental attempts to engineer such a process faced the generation of an excessive number of errors that overwhelmed the error-correcting capability of the process itself. Whether it is practically possible to utilize QEC for extending quantum coherence thus remains an open question. Here we answer it by demonstrating a fully stabilized and error-corrected logical qubit whose quantum coherence is substantially longer than that of all the imperfect quantum components involved in the QEC process, beating the best of them with a coherence gain of G = 2.27 ± 0.07. We achieve this performance by combining innovations in several domains including the fabrication of superconducting quantum circuits and model-free reinforcement learning."

Doubling a qubit’s life, researchers prove a key theory of quantum physics | Yale School of Engineering & Applied Science

Real-time quantum error correction beyond break-even (no public access)

Fig. 1: Experimental system