Nonuniform code concatenation for universal fault-tolerant quantum computing

On Universal and Fault-Tolerant Quantum Computing

Toward fault-tolerant quantum computation without concatenation

It has been known that quantum error correction via concatenated codes can be done with exponentially small failure rate if the error rate for physical qubits is below a certain accuracy threshold. Other, unconcatenated codes with their own attractive features—improved accuracy threshold, local operations—have also been studied. By iteratively distilling a certain two-qubit entangled state it i...

Resource optimization for fault-tolerant quantum computing

Quantum computing offers the potential for efficiently solving otherwise classically difficult problems, with applications in material and drug design, cryptography, theoretical physics, number theory and more. However, quantum systems are notoriously fragile; interaction with the surrounding environment and lack of precise control constitute noise, which makes construction of a reliable quantu...

Threshold Estimate for Fault Tolerant Quantum Computing

I make a rough estimate of the accuracy threshold for fault tolerant quantum computing with concatenated codes. First I consider only gate errors and use the depolarizing channel error model. I will follow P.Shor [1] for fault tolerant error correction (FTEC) and the fault tolerant implementation of elementary operations on states encoded by the 7-qubit code. A simple computer simulation sugges...

Fault-tolerant Computation without Concatenation

It has been known that error-correction via concatenated codes can be done with exponentially small failure rate if the error rate for physical qubits is below a certain accuracy threshold (probably ∼ 10–10). Other, un-concatenated codes with their own attractive features—e.g., an accuracy threshold ∼ 10—have also been studied. A method to obtain universal computation is presented here which do...