Probabilistic state synthesis based on optimal convex approximation

Fuente: arXiv
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Autori principali: Akibue, Seiseki, Kato, Go, Tani, Seiichiro
Natura: Preprint
Pubblicazione: 2023
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author Akibue, Seiseki
Kato, Go
Tani, Seiichiro
author_facet Akibue, Seiseki
Kato, Go
Tani, Seiichiro
contents When preparing a pure state with a quantum circuit, there is an unavoidable approximation error due to the compilation error in fault-tolerant implementation. A recently proposed approach called probabilistic state synthesis, where the circuit is probabilistically sampled, is able to reduce the approximation error compared to conventional deterministic synthesis. In this paper, we demonstrate that the optimal probabilistic synthesis quadratically reduces the approximation error. Moreover, we show that a deterministic synthesis algorithm can be efficiently converted into a probabilistic one that achieves this quadratic error reduction. We also numerically demonstrate how this conversion reduces the $T$-count and analytically prove that this conversion halves an information-theoretic lower bound on the circuit size. In order to derive these results, we prove general theorems about the optimal convex approximation of a quantum state. Furthermore, we demonstrate that this theorem can be used to analyze an entanglement measure.
format Preprint
id arxiv_https___arxiv_org_abs_2303_10860
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Probabilistic state synthesis based on optimal convex approximation
Akibue, Seiseki
Kato, Go
Tani, Seiichiro
Quantum Physics
Mathematical Physics
When preparing a pure state with a quantum circuit, there is an unavoidable approximation error due to the compilation error in fault-tolerant implementation. A recently proposed approach called probabilistic state synthesis, where the circuit is probabilistically sampled, is able to reduce the approximation error compared to conventional deterministic synthesis. In this paper, we demonstrate that the optimal probabilistic synthesis quadratically reduces the approximation error. Moreover, we show that a deterministic synthesis algorithm can be efficiently converted into a probabilistic one that achieves this quadratic error reduction. We also numerically demonstrate how this conversion reduces the $T$-count and analytically prove that this conversion halves an information-theoretic lower bound on the circuit size. In order to derive these results, we prove general theorems about the optimal convex approximation of a quantum state. Furthermore, we demonstrate that this theorem can be used to analyze an entanglement measure.
title Probabilistic state synthesis based on optimal convex approximation
topic Quantum Physics
Mathematical Physics
url https://arxiv.org/abs/2303.10860