Satoshi Yoshida

Assistant professor @UTokyo_Science / Quantum information theory

[Satoshi Yoshida @sy_3104]

Our paper “Quantum Advantage in Storage and Retrieval of Isometry Channels” has been published in Physical Review Letters as Editor’s Suggestion!
https://t.co/zTfdQoFfwB

A press release has been published on this paper:
https://t.co/bvfmTc8H3a

[Physical Review Letters @PhysRevLett]

For isometry channels, quantum protocols based on port-based teleportation outperform classical estimate-and-prepare strategies in terms of both query complexity and program cost, achieving a provable asymptotic advantage https://t.co/zRDxZUDLU7

[東京大学 | UTokyo @UTokyo_News]

[プレスリリース] 量子演算の効率的な保存・再生――量子メモリが古典メモリの性能を上回ることを理論的に証明―――理学系研究科・理学部
https://t.co/nhNagqsd5Y

[Satoshi Yoshida @sy_3104]

アイソメトリ演算の保存・再生における量子戦略の優位性を示した論文がPhysical Review LettersのEditor’s Suggestionに選ばれました！
https://t.co/zTfdQoFfwB

本件に関してプレスリリースを出しました:
https://t.co/X3P6zn7k4V

[Satoshi Yoshida @sy_3104]

本日付で東京大学大学院理学系研究科物理学専攻の助教に着任しました。今後ともよろしくお願いします。

[Satoshi Yoshida @sy_3104]

昨日博士(理学)が授与され、東大での9年間の学生生活に幕が下りました。これからも研究に精進します！

[Satoshi Yoshida @sy_3104]

I got a PhD yesterday, and my 9-year student life at UTokyo is now over!

[Hayata Yamasaki @HayataYamasaki]

4月から東大院講義「量子情報と量子計算」を開講します。第一線の研究者をゲストに迎え、基礎的なチュートリアルから最新の研究動向まで学びます。量子アーキテクチャ、誤り訂正、暗号、アルゴリズムなど理論のテーマを広く扱い、質疑・議論も行うのでぜひ！参加登録(連絡用):
https://t.co/WpTsrR5pWg

[Hayata Yamasaki @HayataYamasaki]

Paper uploaded. We rigorously prove a finite fault-tolerance threshold for the union-find decoder under circuit-level noise. Our analysis also shows its quasi-polylogarithmic average runtime in the code size. Joint work with Satoshi Yoshida and Ethan Lake. https://t.co/7ZIacAarfK

[Satoshi Yoshida @sy_3104]

Two constructions are shown in this work, and one also appears in an independent work https://t.co/6t4nKpvfT7 (one day earlier than us).

[Satoshi Yoshida @sy_3104]

We present a quantum circuit transforming an unknown quantum channel to parallel queries of randomly chosen dilation isometry of the input channel. As applications, we show storage-and-retrieval, superreplication, and Petz recovery map algorithms.
https://t.co/UP2AskRmwZ

[Satoshi Yoshida @sy_3104]

Published in Nature Communications!
https://t.co/EPCXMVxiMV

[Satoshi Yoshida @sy_3104]

We show that simulation of quantum switch with standard quantum circuit is exponentially hard, even with multiple queries to one input channel!
https://t.co/YjGpmuM0CE

[Satoshi Yoshida @sy_3104]

In our companion paper, we show no-go theorems in more general settings (probabilistic, approximate and multiple queries to both input channels) by computer-assisted proof, mainly done by Jessica and Marco.
https://t.co/587PQJLoeM

[Satoshi Yoshida @sy_3104]

New work!
We establish a canonical circuit decomposition of any quantum comb with group invariance or covariance. This framework allows for a significant reduction in the number of parameters subject to optimization of the quantum comb.
https://t.co/NyGZrtDn78

[Craig Gidney @CraigGidney]

For their student researcher-ship, Satoshi Yoshida extended our work on dynamic surface code circuits to color codes. They built and simulated iswap color code circuits and wiggling color code circuits. The iswap circuits use fewer layers than CX ones!

https://t.co/l1ZFvA05HN

[Satoshi Yoshida @sy_3104]

New paper on QEC!
We propose two new types of syndrome extraction circuits for the color code. One mitigates leakage errors by interchanging the roles of measurement and data qubits. The other reduces the depth by using CXSWAP gates instead of CNOT gates.
https://t.co/L1Phq97XIf

[Satoshi Yoshida @sy_3104]

New work on random unitary!
We construct an exact simulator of a random unitary for any compact group, allowing forward, backward, conjugate, and transpose queries. We also show an efficient quantum circuit for the forward query of the unitary group.
https://t.co/H7gq8PR4qH

[Satoshi Yoshida @sy_3104]

New work is out!
We show the optimal infidelity of estimating unknown qutrit-unitary channel up to a leading order. The proof of optimality utilizes reduction of graph Laplacian eigenvalue problem to the continuous one using the finite element method.
https://t.co/u7Bogeq5UO

[Satoshi Yoshida @sy_3104]

Our new work is out!

We show quantum advantage in storage and retrieval of isometry channels, while classical strategy is optimal for unitary channels. This difference comes from “phase transition” in estimation error of isometry channel.

https://t.co/IEplxxrn6e

[Satoshi Yoshida @sy_3104]

@CraigGidney Thank you for your question! We discuss the reason why we report lower threshold than previous works in Sec. B of the Supplementary Information, and the detail of the analysis is shown in Sec. A2b.
If you need detailed discussions, let’s continue in the email!

[Satoshi Yoshida @sy_3104]

Our FTQC paper is out! We construct a fault-tolerant protocol based on concatenated codes, achieving a substantially lower space overhead and a higher threshold than that for the surface code. This is a joint work with @Shiro_Tamiya and @HayataYamasaki.
https://t.co/l7F7gy2aG1