Harvard Led Group Demonstration of Complex Error-Corrected Quantum Algorithm on 48 Logical Qubits

We have entered the start of new era of error corrected quantum computers. There has been a journal Nature paper on the work of a 48 logical qubit error corrected system by researchers from Harvard, MIT, QuEra and NIST/Maryland Usher.

There is another article that gives the state of quantum error correction today.

There is another article that describes how 1500 error corrected qubits could be a major problem for bitcoin and cryptocurrency.

Nature – Logical quantum processor based on reconfigurable atom arrays

Abstract
Suppressing errors is the central challenge for useful quantum computing1, requiring quantum error correction for large-scale processing. However, the overhead in the realization of error-corrected “logical” qubits, where information is encoded across many physical qubits for redundancy poses significant challenges to large-scale logical quantum computing. Here we report the realization of a programmable quantum processor based on encoded logical qubits operating with up to 280 physical qubits. Utilizing logical-level control and a zoned architecture in reconfigurable neutral atom arrays, our system combines high two-qubit gate fidelities, arbitrary connectivity as well as fully programmable single-qubit rotations and mid-circuit readout. Operating this logical processor with various types of encodings, we demonstrate improvement of a two-qubit logic gate by scaling surface code distance from d = 3 to d = 7, preparation of color code qubits with break-even fidelities, fault-tolerant creation of logical GHZ states and feedforward entanglement teleportation, as well as operation of 40 color code qubits. Finally, using three-dimensional [[8,3,2]] code blocks we realize computationally complex sampling circuits with up to 48 logical qubits entangled with hypercube connectivity with 228 logical two-qubit gates and 48 logical CCZ gates. We find that this logical encoding substantially improves algorithmic performance with error detection, outperforming physical qubit fidelities at both cross-entropy benchmarking and quantum simulations of fast scrambling. These results herald the advent of early error-corrected quantum computation and chart a path toward large-scale logical processors.

NOTE: They did error detection and the surface code distance was not a very robust error correction. Speaking with John Preskill there is still a couple of years of work to improve this QuEra work to a more complete error correction repeated error correction.