“Until now researchers have actually encoded and stabilized. We now reveal that we can calculate as well.”
Scientists at QuTech– a partnership between the TU Delft and TNO– have actually reached a milestone in quantum error correction. They have actually incorporated high-fidelity operations on encoded quantum information with a scalable plan for duplicated information stabilization. The researchers report their findings in the December issue of Nature Physics.
More qubits
Physical quantum bits, or qubits, are susceptible to errors. These mistakes arise from different sources, consisting of quantum decoherence, crosstalk, and imperfect calibration. The theory of quantum mistake correction states the possibility to calculate while synchronously securing quantum information from such errors.
” Two abilities will differentiate an error remedied quantum computer system from present-day noisy intermediate-scale quantum (NISQ) processors”, says Prof Leonardo DiCarlo of QuTech. According to theory, the logical mistake rate can be tremendously suppressed provided that the occurrence of physical mistakes is below a threshold and the circuits for rational operations and stabilization are fault tolerant.
Artistic image of a seven-transmon superconducting quantum processor similar to the one used in this work. Credit: DiCarlo Lab and Marieke de Lorijn
All the operations
The standard concept thus is that if you increase the redundancy and use more and more qubits to encode data, the net mistake goes down. The scientists at TU Delft, together with colleagues at TNO, have actually now understood a major step towards this goal, realizing a logical qubit including seven physical qubits (superconducting transmons). “We show that we can do all the operations needed for computation with the encoded information. This combination of high-fidelity sensible operations with a scalable plan for duplicated stabilization is an essential action in quantum mistake correction”, says Prof Barbara Terhal, likewise of QuTech.
This is what a fault-tolerant computer must ultimately do: process and secure information from mistakes all at the exact same time. We do three types of logical-qubit operations: initializing the sensible qubit in any state, transforming it with gates, and determining it. Fault-tolerant operations are crucial to decreasing the build-up of physical-qubit errors into logical-qubit errors.
Long term
DiCarlo emphasizes the multidisciplinary nature of the work: “This is a combined effort of experimental physics, theoretical physics from Barbara Terhals group, and likewise electronics developed with TNO and external partners. The task is generally moneyed by IARPA and Intel Corporation.”
” Our grand goal is to show that as we increase encoding redundancy, the net mistake rate in fact decreases significantly”, DiCarlo concludes. “Our present focus is on 17 physical qubits and next up will be 49. All layers of our quantum computers architecture were created to permit this scaling.”
Reference: “Logical-qubit operations in an error-detecting surface code” by J. F. Marques, B. M. Varbanov, M. S. Moreira, H. Ali, N. Muthusubramanian, C. Zachariadis, F. Battistel, M. Beekman, N. Haider, W. Vlothuizen, A. Bruno, B. M. Terhal and L. DiCarlo, 16 December 2021, Nature Physics.DOI: 10.1038/ s41567-021-01423-9.
Physical quantum bits, or qubits, are susceptible to mistakes. The theory of quantum mistake correction states the possibility to calculate while synchronously safeguarding quantum data from such errors.
” Two abilities will distinguish a mistake corrected quantum computer from contemporary noisy intermediate-scale quantum (NISQ) processors”, states Prof Leonardo DiCarlo of QuTech. According to theory, the sensible error rate can be significantly suppressed supplied that the occurrence of physical errors is listed below a threshold and the circuits for logical operations and stabilization are fault tolerant.
Fault-tolerant operations are crucial to decreasing the accumulation of physical-qubit mistakes into logical-qubit mistakes.