

External AwardsThe Commendation for Science and Technology by the Minister of Education, Culture, Sports, Science and Technology, Award for Science and Technology in Research CategoryWinner: Hiroki Takesue, NTT Basic Research Laboratories Date: April 8, 2022 Organization: Ministry of Education, Culture, Sports, Science and Technology For his achievements in quantum communications such as quantum key distribution and quantum entanglement generation for the telecommunication band and coherent Ising machines based on optical parametric oscillators. The Commendation for Science and Technology by the Minister of Education, Culture, Sports, Science and Technology, the Young Scientists’ AwardWinner: Koji Azuma, NTT Basic Research Laboratories Date: April 8, 2022 Organization: Ministry of Education, Culture, Sports, Science and Technology For his achievements in theory of quantum repeaters necessary for the development of a quantum internet. IEICE Communications Society Excellent Paper Award, Best Paper AwardWinners: Yuya Omori, NTT Computer and Data Science Laboratories/NTT Device Innovation Center; Ken Nakamura, NTT Computer and Data Science Laboratories/NTT Device Innovation Center; Takayuki Onishi, NTT Computer and Data Science Laboratories; Daisuke Kobayshi, NTT Computer and Data Science Laboratories/NTT Device Innovation Center; Tatsuya Osawa, NTT Corporate Strategy Planning Department; Hiroe Iwasaki, Tokyo University of Agriculture and Technology Date: May 11, 2022 Organization: The Institute of Electronics, Information and Communication Engineers (IEICE) For “4K 120fps HEVC Encoder with Multichip Configuration.” Published as: Y. Omori, K. Nakamura, T. Onishi, D. Kobayshi, T. Osawa, and H. Iwasaki, “4K 120fps HEVC Encoder with Multichip Configuration,” IEICE Transactions on Communications, Vol. E104B, No. 7, pp. 749–759, 2021. Papers Published in Technical Journals and Conference ProceedingsDitherfree Bias Condition Monitoring Technique Utilizing Reference Light for Inservice Optical IQ modulatorH. Kawakami, S. Kuwahara, and Y. Kisaka 27th OptoElectronics and Communications Conference (OECC 2022), TuPB7, Toyama, Japan, July 2022. We developed a ditherfree bias condition monitoring technique for IQ modulators utilizing reference light and a lowspeed power monitor. Experimental results for confirming the principle are also shown. Divideandconquer Verification Method for Noisy Intermediatescale Quantum ComputationY. Takeuchi, Y. Takahashi, T. Morimae, and S. Tani Quantum, Vol. 6, p. 758, July 2022. Several noisy intermediatescale quantum computations can be regarded as logarithmicdepth quantum circuits on a sparse quantum computing chip, where twoqubit gates can be directly applied on only some pairs of qubits. In this paper, we propose a method to efficiently verify such noisy intermediatescale quantum computation. To this end, we first characterize smallscale quantum operations with respect to the diamond norm. Then by using these characterized quantum operations, we estimate the fidelity ⟨ψ_{t}ψ_{t}⟩ between an actual nqubit output state obtained from the noisy intermediatescale quantum computation and the ideal output state (i.e., the target state) ψ_{t}⟩. Although the direct fidelity estimation method requires O(2^{n}) copies of on average, our method requires only O(D^{3}2^{12}^{D}) copies even in the worst case, where D is the denseness of ψ_{t}⟩. For logarithmicdepth quantum circuits on a sparse chip, D is at most O(log n), and thus O(D^{3}2^{12}^{D}) is a polynomial in n. By using the IBM Manila 5qubit chip, we also perform a proofofprinciple experiment to observe the practical performance of our method. Passive Verification Protocol for Thermal Graph StatesK. Akimoto, S. Tsuchiya, R. Yoshii, and Y. Takeuchi Physical Review A, Vol. 106, 012405, July 2022. Graph states are entangled resource states for universal measurementbased quantum computation. Although matter qubits such as superconducting circuits and trapped ions are promising candidates to generate graph states, it is technologically hard to entangle a large number of them due to several types of noise. Since they must be sufficiently cooled to maintain their quantum properties, thermal noise is one of the major ones. In this paper, we show that, for any temperature T, the fidelity ⟨Gρ_{T}G⟩ between an ideal graph state G⟩ at zero temperature and a thermal graph state ρ_{T}, which is a graph state at temperature T, can be efficiently estimated by using only one measurement setting. A remarkable property of our protocol is that it is passive, while existing protocols are active, namely, they switch between at least two measurement settings. Since thermal noise is equivalent to an independent phaseflip error, our estimation protocol also works for that error. By generalizing our protocol to hypergraph states, we apply our protocol to the quantumcomputationalsupremacy demonstration with instantaneous quantum polynomial time circuits. Our results should make the characterization of entangled matter qubits extremely feasible under thermal noise. Computational Selftesting for Entangled Magic StatesA. Mizutani, Y. Takeuchi, R. Hiromasa, Y. Aikawa, and S. Tani Physical Review A, Vol. 106, L010601, July 2022. Can classical systems grasp quantum dynamics executed in an untrusted quantum device? Metger and Vidick answered this question affirmatively by proposing a computational selftesting protocol for Bell states that certifies generation of Bell states and measurements on them. Since their protocol relies on the fact that the target states are stabilizer states, it is highly nontrivial to reveal whether the other class of quantum states, nonstabilizer states, can be selftested. Among nonstabilizer states, magic states are indispensable resources for universal quantum computation. Here, we show that a magic state for the CCZ gate can be selftested while that for the T gate cannot. Our result is applicable to a proof of quantumness, where we can classically verify whether a quantum device generates a quantum state having nonzero magic. 