Pan’s and Wallraff’s groups are the first to successfully implement the smallest (with a distance of three) error-correcting surface code. With surface codes the connections between elements of the quantum computer can be visualized as forming a 2D checkerboard pattern.
#QUANTUM ERROR CODE#
“The number of physical qubits used to encode a logical qubit is called the distance of the code, and a code gets exponentially better at suppressing logical errors as the distance increases (at the cost of increased hardware complexity),” wrote Frunzio and Singh. QEC schemes involve redundantly encoding quantum information of a single “logical” qubit in a many-body entangled state of multiple “physical” qubits so that comparisons between these qubits reveal if one or more of them has changed. The brief Frunzio-Singh article is a succinct overview of the recent work and also of quantum error correction. Lett.129, 030501 (2022) Krinner et al., “Realizing repeated quantum error correction in a distance-three surface code,” Nature 605, 669 (2022). Zhao et al., “Realization of an error-correcting surface code with superconducting qubits,” Phys. After two-plus years of contentious debate, several different names, and final passage by the House (243-187) and Senate (64-33) last week, the Chips and Science Act will soon become law. These results bring us a step closer toward realizing a practical quantum computer.”īoth groups have recently published papers on their work: Y. Not Just Cash for Chips The New Chips and Science Act Boosts NSF, DOE, NIST. Now, two groups, led by Jian-Wei Pan at the University of Science and Technology of China in Hefei and Andreas Wallraff at the Swiss Federal Institute of Technology (ETH) in Zurich, have achieved the first-ever demonstration of error correction with surface codes. But until now, demonstrations with the surface code have only detected errors, not corrected them. There’s a short, excellent account of the work (Error-Correcting Surface Codes Get Experimental Vetting) written by Luigi Frunzio and Shraddha Singh and posted today on the APS physics website.Īs explained by the authors, “These codes are promising because they are experimentally straightforward to implement and because, under certain conditions, they can tolerate relatively large error rates. Recently, separate teams of researchers reported progress in demonstrating not only error detection but also error correction using so-called surface codes. Robust quantum error correction (QEC) is a necessary ingredient for achieving practical quantum computing and as you might expect there’s an abundance of ongoing work in the area. Our protocol is applicable to other continuous-variable systems and, in contrast to previous implementations of QEC 10-14, can mitigate all logical errors generated by a wide variety of noise processes and facilitate fault-tolerant quantum computation.Since 1987 - Covering the Fastest Computers in the World and the People Who Run Them We demonstrate QEC of an encoded qubit with suppression of all logical errors, in quantitative agreement with a theoretical estimate based on the measured imperfections of the experiment. Here we experimentally prepare square and hexagonal GKP code states through a feedback protocol that incorporates non-destructive measurements that are implemented with a superconducting microwave cavity having the role of the oscillator. However, the implementation of measurements that reveal this noise-induced evolution of the oscillator while preserving the encoded information 3-7 has proved to be experimentally challenging, and the only realization reported so far relied on post-selection 8,9, which is incompatible with QEC. In 2001, Gottesman, Kitaev and Preskill (GKP) proposed a hardware-efficient instance of such a non-local qubit: a superposition of position eigenstates that forms grid states of a single oscillator 2. Therefore, if a logical qubit is encoded non-locally, we can-for a limited time-detect and correct noise-induced evolution before it corrupts the encoded information 1. This approach derives from the reasonable assumption that noise is local, that is, it does not act in a coordinated way on different parts of the physical system. One method to achieve this is quantum error correction (QEC), which prevents noise in the underlying system from causing logical errors. The accuracy of logical operations on quantum bits (qubits) must be improved for quantum computers to outperform classical ones in useful tasks.
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