Logical Blocks for Fault-Tolerant Topological Quantum Computation

Logical gates constitute the building blocks of fault-tolerant quantum computation. While quantum error-corrected memories have been extensively studied in the literature, explicit constructions and detailed analyses of thresholds and resource overheads of universal logical gate sets have so far bee...

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Glavni autori: Héctor Bombín, Chris Dawson, Ryan V. Mishmash, Naomi Nickerson, Fernando Pastawski, Sam Roberts
Format: Članak
Jezik:English
Izdano: American Physical Society 2023-04-01
Serija:PRX Quantum
Online pristup:http://doi.org/10.1103/PRXQuantum.4.020303
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author Héctor Bombín
Chris Dawson
Ryan V. Mishmash
Naomi Nickerson
Fernando Pastawski
Sam Roberts
author_facet Héctor Bombín
Chris Dawson
Ryan V. Mishmash
Naomi Nickerson
Fernando Pastawski
Sam Roberts
author_sort Héctor Bombín
collection DOAJ
description Logical gates constitute the building blocks of fault-tolerant quantum computation. While quantum error-corrected memories have been extensively studied in the literature, explicit constructions and detailed analyses of thresholds and resource overheads of universal logical gate sets have so far been limited. In this paper, we present a comprehensive framework for universal fault-tolerant logic motivated by the combined need for (i) platform-independent logical gate definitions, (ii) flexible and scalable tools for numerical analysis, and (iii) exploration of novel schemes for universal logic that improve resource overheads. Central to our framework is the description of logical gates holistically in a way that treats space and time on a similar footing. Focusing on instruments based on surface codes, we introduce explicit, but platform-independent representations of topological logic gates—called logical blocks—and generate new, overhead-efficient methods for universal quantum computation. As a specific example, we propose fault-tolerant schemes based on surface codes concatenated with more general low-density parity check (LDPC) codes, suggesting an alternative path toward LDPC-based quantum computation. The logical blocks framework enables a convenient software-based mapping from an abstract description of the logical gate to a precise set of physical instructions for executing both circuit-based and fusion-based quantum computation (FBQC). Using this, we numerically simulate a surface-code-based universal gate set implemented with FBQC, and verify that the threshold for fault-tolerant gates is consistent with the bulk threshold for memory. We find, however, that boundaries, defects, and twists can significantly impact the logical error rate scaling, with periodic boundary conditions potentially halving resource requirements. Motivated by the favorable logical error rate suppression for boundaryless computation, we introduce a novel computational scheme based on the teleportation of twists that may offer further resource reductions.
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spelling doaj.art-f09c3e7e16944d0e9644dba4a5a8c8752023-04-07T15:02:07ZengAmerican Physical SocietyPRX Quantum2691-33992023-04-014202030310.1103/PRXQuantum.4.020303Logical Blocks for Fault-Tolerant Topological Quantum ComputationHéctor BombínChris DawsonRyan V. MishmashNaomi NickersonFernando PastawskiSam RobertsLogical gates constitute the building blocks of fault-tolerant quantum computation. While quantum error-corrected memories have been extensively studied in the literature, explicit constructions and detailed analyses of thresholds and resource overheads of universal logical gate sets have so far been limited. In this paper, we present a comprehensive framework for universal fault-tolerant logic motivated by the combined need for (i) platform-independent logical gate definitions, (ii) flexible and scalable tools for numerical analysis, and (iii) exploration of novel schemes for universal logic that improve resource overheads. Central to our framework is the description of logical gates holistically in a way that treats space and time on a similar footing. Focusing on instruments based on surface codes, we introduce explicit, but platform-independent representations of topological logic gates—called logical blocks—and generate new, overhead-efficient methods for universal quantum computation. As a specific example, we propose fault-tolerant schemes based on surface codes concatenated with more general low-density parity check (LDPC) codes, suggesting an alternative path toward LDPC-based quantum computation. The logical blocks framework enables a convenient software-based mapping from an abstract description of the logical gate to a precise set of physical instructions for executing both circuit-based and fusion-based quantum computation (FBQC). Using this, we numerically simulate a surface-code-based universal gate set implemented with FBQC, and verify that the threshold for fault-tolerant gates is consistent with the bulk threshold for memory. We find, however, that boundaries, defects, and twists can significantly impact the logical error rate scaling, with periodic boundary conditions potentially halving resource requirements. Motivated by the favorable logical error rate suppression for boundaryless computation, we introduce a novel computational scheme based on the teleportation of twists that may offer further resource reductions.http://doi.org/10.1103/PRXQuantum.4.020303
spellingShingle Héctor Bombín
Chris Dawson
Ryan V. Mishmash
Naomi Nickerson
Fernando Pastawski
Sam Roberts
Logical Blocks for Fault-Tolerant Topological Quantum Computation
PRX Quantum
title Logical Blocks for Fault-Tolerant Topological Quantum Computation
title_full Logical Blocks for Fault-Tolerant Topological Quantum Computation
title_fullStr Logical Blocks for Fault-Tolerant Topological Quantum Computation
title_full_unstemmed Logical Blocks for Fault-Tolerant Topological Quantum Computation
title_short Logical Blocks for Fault-Tolerant Topological Quantum Computation
title_sort logical blocks for fault tolerant topological quantum computation
url http://doi.org/10.1103/PRXQuantum.4.020303
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