General Entropic Constraints on Calderbank-Shor-Steane Codes within Magic Distillation Protocols
General Entropic Constraints on Calderbank-Shor-Steane Codes within Magic Distillation Protocols
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DOI:
10.1103/prxquantum.4.020359
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发表时间:
2022-11
期刊:
影响因子:
9.7
通讯作者:
Rhea Alexander;Si Gvirtz-Chen;Nikolaos Koukoulekidis;D. Jennings
中科院分区:
文献类型:
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作者:
Rhea Alexander;Si Gvirtz-Chen;Nikolaos Koukoulekidis;D. Jennings
Magic states are fundamental building blocks on the road to fault-tolerant quantum computing. CSS codes play a crucial role in the construction of magic distillation protocols. Previous work has cast quantum computing with magic states for odd dimension $d$ within a phase space setting in which universal quantum computing is described by the statistical mechanics of quasiprobability distributions. Here we extend this framework to the important $d=2$ qubit case and show that we can exploit common structures in CSS circuits to obtain distillation bounds capable of out-performing previous monotone bounds in regimes of practical interest. Moreover, in the case of CSS code projections, we arrive at a novel cut-off result on the code length $n$ of the CSS code in terms of parameters characterising a desired distillation, which implies that for fixed target error rate and acceptance probability, one needs only consider CSS codes below a threshold number of qubits. These entropic constraints are not due simply to the data-processing inequality but rely explicitly on the stochastic representation of such protocols.