小川 朋宏
| 情報・ネットワーク工学専攻 | 准教授 |
| Ⅱ類（融合系） | 准教授 |
| 先端工学基礎課程（夜間主課程） | 准教授 |
| 量子科学研究センター | 准教授 |
研究者情報
研究キーワード
経歴
研究活動情報
論文
- Asymptotic Convertibility of Entanglement: An Information-Spectrum Approach to Entanglement Concentration and Dilution
Yong Jiao; Eyuri Wakakuwa; Tomohiro Ogawa
J. Math. Phys., 59巻, 掲載ページ 022201, 出版日 2018年, 査読付
研究論文（学術雑誌）, 英語 - Strong Converse Exponent for Classical-Quantum Channel Coding
Milan Mosonyi; Tomohiro Ogawa
COMMUNICATIONS IN MATHEMATICAL PHYSICS, SPRINGER, 355巻, 1号, 掲載ページ 373-426, 出版日 2017年10月, 査読付, We determine the exact strong converse exponent of classical-quantum channel coding, for every rate above the Holevo capacity. Our form of the exponent is an exact analogue of Arimoto's, given as a transform of the R,nyi capacities with parameters . It is important to note that, unlike in the classical case, there are many inequivalent ways to define the R,nyi divergence of states, and hence the R,nyi capacities of channels. Our exponent is in terms of the R,nyi capacities corresponding to a version of the R,nyi divergences that has been introduced recently in Muller-Lennert et al. (J Math Phys 54(12):122203, 2013.). Our result adds to the growing body of evidence that this new version is the natural definition for the purposes of strong converse problems.
研究論文（学術雑誌）, 英語 - Two Approaches to Obtain the Strong Converse Exponent of Quantum Hypothesis Testing for General Sequences of Quantum States
Milan Mosonyi; Tomohiro Ogawa
IEEE TRANSACTIONS ON INFORMATION THEORY, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 61巻, 12号, 掲載ページ 6975-6994, 出版日 2015年12月, 査読付, We present two general approaches to obtain the strong converse exponent of simple quantum hypothesis testing for correlated quantum states. One approach requires that the states satisfy a certain factorization property; typical examples of such states are the temperature states of translation-invariant finite-range interactions on a spin chain. The other approach requires the differentiability of a regularized Renyi alpha-divergence in the parameter a; typical examples of such states include temperature states of non-interacting fermionic lattice systems, and classical irreducible Markov chains. In all cases, we get that the strong converse exponent is equal to the Hoeffding anti-divergence, which in turn is obtained from the regularized Renyi divergences of the two states.
研究論文（学術雑誌）, 英語 - Quantum Hypothesis Testing and the Operational Interpretation of the Quantum Renyi Relative Entropies
Milan Mosonyi; Tomohiro Ogawa
COMMUNICATIONS IN MATHEMATICAL PHYSICS, SPRINGER, 334巻, 3号, 掲載ページ 1617-1648, 出版日 2015年03月, 査読付, We show that the new quantum extension of Renyi's alpha-relative entropies, introduced recently by Muller-Lennert et al. (J Math Phys 54: 122203, 2013) and Wilde et al. (Commun Math Phys 331(2): 593-622, 2014), have an operational interpretation in the strong converse problem of quantum hypothesis testing. Together with related results for the direct part of quantum hypothesis testing, known as the quantum Hoeffding bound, our result suggests that the operationally relevant definition of the quantum Renyi relative entropies depends on the parameter alpha: for alpha < 1, the right choice seems to be the traditional definition D-alpha((old)) (rho parallel to sigma) := 1/alpha-1 log Tr rho(alpha)sigma(1-alpha), whereas for alpha > 1 the right choice is the newly introduced version D-alpha((new)) (rho parallel to sigma) := 1/alpha-1 log Tr (sigma 1-alpha/2 alpha rho sigma 1-alpha/2 alpha)(alpha).
On the way to proving our main result, we show that the new Renyi alpha-relative entropies are asymptotically attainable by measurements for alpha > 1. From this, we obtain a new simple proof for their monotonicity under completely positive trace-preserving maps.
研究論文（学術雑誌）, 英語 - Error Exponents in Hypothesis Testing for Correlated States on a Spin Chain
Fumio Hiai; Milan Mosonyi; Tomohiro Ogawa
Journal of Mathematical Physics, 49巻, 掲載ページ 032112, 出版日 2008年, 査読付
研究論文（学術雑誌）, 英語 - Asymptotic Distinguishability Measures for Shift-invariant Quasi-free States of Fermionic Lattice Systems
Milan Mosonyi; Fumio Hiai; Tomohiro Ogawa; Mark Fannes
Journal of Mathematical Physics, 49巻, 掲載ページ 072104, 出版日 2008年, 査読付
研究論文（学術雑誌）, 英語 - Making good codes for classical-quantum channel coding via quantum hypothesis testing
Tomohiro Ogawa; Hiroshi Nagaoka
IEEE TRANSACTIONS ON INFORMATION THEORY, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 53巻, 6号, 掲載ページ 2261-2266, 出版日 2007年06月, 査読付, In this correspondence, we give an alternative proof of the direct part of the classical-quantum channel coding theorem (the Holevo-Schumacher-Westmoreland (HSW) theorem), using ideas of quantum hypothesis testing. In order to show the existence of good codes, we invoke a limit theorem, relevant to the quantum Stein's lemma, in quantum hypothesis testing as the law of large numbers used in the classical case. We also apply a greedy construction of good codes using a packing procedure of noncommutative operators. Consequently we derive an upper bound on the coding error probability, which is used to give an alternative proof of the HSW theorem. This approach elucidates how the Holevo information applies to the classical-quantum channel coding problems.
研究論文（学術雑誌）, 英語 - 量子通信路の漸近的可逆性
小川朋宏
数理解析研究所講究録, 1534巻, 掲載ページ 108-118, 出版日 2007年
研究論文（大学，研究機関等紀要）, 日本語 - Large Deviations and Chernoff Bound for Certain Correlated States on the Spin Chain
Fumio Hiai; Milan Mosonyi; Tomohiro Ogawa
Journal of Mathematical Physics, 48巻, 掲載ページ 123301, 出版日 2007年, 査読付
研究論文（学術雑誌）, 英語 - On the Statistical Equivalence for Sets of Quantum States
Tomohiro Ogawa; Hiroshi Nagaoka
Technical Report: University of Electro-Communicatios, 掲載ページ UEC-IS-2005-5, 出版日 2005年
研究論文（大学，研究機関等紀要）, 英語 - On the Markov Equivalence for Sets of Probability Distributions
Hiroshi Nagaoka; Tomohiro Ogawa
Technical Report: University of Electro-Communicatios, 掲載ページ UEC-IS-2005-4, 出版日 2005年
研究論文（大学，研究機関等紀要）, 英語 - Quantum Secret Sharing Schemes and Reversibility of Quantum Operations
Tomohiro Ogawa; Akira Sasaki; Mitsugu Iwamoto; Hirosuke Yamamoto
Physical Review A, 掲載ページ 032318, 出版日 2005年, 査読付
研究論文（学術雑誌）, 英語 - On Error Exponents in Quantum Hypothesis Testing
Tomohiro Ogawa; Masahito Hayashi
IEEE Trans. Infrom. Theory, 50巻, 6号, 掲載ページ 1368-1372, 出版日 2004年, 査読付
研究論文（学術雑誌）, 英語 - Strong converse and Stein's lemma in quantum hypothesis testing
T Ogawa; H Nagaoka
IEEE TRANSACTIONS ON INFORMATION THEORY, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 46巻, 7号, 掲載ページ 2428-2433, 出版日 2000年11月, 査読付, The hypothesis testing problem for two quantum states is treated. We show a new inequality between the errors of the first kind and the second kind, which complements the result of Hiai and Petz to establish the quantum version of Stein's lemma. The inequality is also used to show a bound on the probability of errors of the first kind when the power exponent for the probability of errors of the second kind exceeds the quantum relative entropy, which yields the strong converse in quantum hypothesis testing. Finally, we discuss the relation between the bound and the power exponent derived by Han and Kobayashi in classical hypothesis testing.
研究論文（学術雑誌）, 英語 - Strong converse to the quantum channel coding theorem
T Ogawa; H Nagaoka
IEEE TRANSACTIONS ON INFORMATION THEORY, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 45巻, 7号, 掲載ページ 2486-2489, 出版日 1999年11月, 査読付, A lower bound on the probability of decoding error for a quantum communication channel is presented, from which the strong converse to the quantum channel coding theorem is immediately shown, The results and their derivations are mostly straightforward extensions of the classical counterparts which were established by Arimoto, except that more careful treatment is necessary here due to the noncommutativity of operators.
研究論文（学術雑誌）, 英語
書籍等出版物
- Introduction to Quantum Information Science
Masahito Hayashi; Satoshi Ishizaka; Akinori Kawachi; Gen Kimura; Tomohiro Ogawa
学術書, 英語, 共著, Springer, 出版日 2014年09月03日 - 量子情報科学入門
石坂智; 小川朋宏; 河内亮周; 木村元; 林正人
日本語, 共著, 第５章：量子系における情報量，第７章：量子通信路符号化，付録, 共立出版, 出版日 2012年06月 - 現代数理科学事典 第2版
現代数理科学事典編集委員会
日本語, 共著, VIII-1 量子情報理論, 丸善, 出版日 2009年12月
担当経験のある科目_授業
- Innovative Comprehensive Communications Design 2
The University of Electro-Communications - イノベイティブ総合コミュニケーションデザイン2
電気通信大学 - Algorithms and Data Structures and Programming Exercises
The University of Electro-Communications - アルゴリズムとデータ構造およびプログラミング演習
電気通信大学 - Probability and Statistics
The University of Electro-Communications - 確認統計
電気通信大学 - Advanced Topics on Quantum Information Theory
The University of Electro-Communications - 量子情報数理特論
電気通信大学