Significant technical and financial issues remain towards building a large, fault-tolerant quantum computer and one is unlikely to be built within the coming decade.
A happy accident in the laboratory has led to a breakthrough discovery that not only solved a problem that stood for more than half a century, but has major implications for the development of quantum computers and sensors. [55] Significant technical and financial issues remain towards building a large, fault-tolerant quantum computer and one is unlikely to be built within the coming decade. [54] Chemists at Friedrich Schiller University in Jena (Germany) have now synthesised a molecule that can perform the function of a computing unit in a quantum computer. [53] The research team developed the first optical microchip to generate, manipulate and detect a particular state of light called squeezed vacuum, which is essential for HYPERLINK https://phys.org/tags/quantum/ quantum computation. [52] Australian scientists have investigated new directions to scale up qubits-utilising the spin-orbit coupling of atom qubits-adding a new suite of tools to the armory. [51] A team of international researchers led by engineers from the National University of Singapore (NUS) have invented a new magnetic device to manipulate digital information 20 times more efficiently and with 10 times more stability than commercial spintronic digital memories. [50] Working in the lab of Mikhail Lukin, the George Vasmer Leverett Professor of Physics and co-director of the Quantum Science and Engineering Initiative, Evans is lead author of a study, described in the journal Science, that demonstrates a method for engineering an interaction between two qubits using photons. [49] Researchers with the Department of Energy's Oak Ridge National Laboratory have demonstrated a new level of control over photons encoded with quantum information. [48] Researchers from Intel Corp. and the University of California, Berkeley, are looking beyond current transistor technology and preparing the way for a new type of memory and logic circuit that could someday be in every computer on the planet. [47]
Fault-tolerant quantum computation with quantum error-correcting codes has been considerably developed over the past decade. However, there are still difficult issues, particularly on the resource requirement. For further improvement of fault-tolerant quantum computation, here we propose a soft-decision decoder for quantum error correction and detection by teleportation. This decoder can achieve almost optimal performance for the depolarizing channel. Applying this decoder to Knill's C4/C6 scheme for fault-tolerant quantum computation, which is one of the best schemes so far and relies heavily on error correction and detection by teleportation, we dramatically improve its performance. This leads to substantial reduction of resources.
Fault-tolerant quantum computing (FTQC) has the potential to reliably execute complex calculations by overcoming the problems raised from the errors and noise inherent in quantum systems. This paper builds upon a 2025 report issued by the National Academy of Technologies of France. After recalling the principles that underly the so-called "quantum advantage," the use of error-correcting codes in the design of fault-tolerant quantum computers is discussed. Also explored are the five most advanced physical technologies that can be used to build such computers and the challenges of scaling up to a sufficient size to run useful applications. After highlighting the limits of monolithic qubit integration, the focus turns to increasing the number of available physical qubits by interconnecting several quantum processing modules. The paper concludes with a discussion of technical and economic environments, their performance benchmarks, and their future coexistence with other computing technologies and with supercomputers.