2021年

S. Hakkaku, K. Mitarai,and K. Fujii,
“Sampling-based quasiprobability simulation for fault-tolerant quantum error correction on the surface codes under coherent noise”
Phys. Rev. Research 3, 043130 (2021).  arXiv:2105.04478

F. Kobayashi, K. Mitarai, and K. Fujii,
“Parent Hamiltonian as a benchmark problem for variational quantum eigensolvers” arXiv:2109.11759

Y. Luo, M. Chen, M. Erhard, H. Zhong, D. Wu, H. Tang, Q. Zhao, X. Wang, K. Fujii, L. Li, N. Liu, K. Nemoto, W. J. Munro, C. Lu, A. Zeilinger, and J. Pan,
“Quantum teleportation of physical qubits into logical code-spaces”
Proceedings of the National Academy of Sciences of the United States of America(PNAS) 118, e2026250118 (2021). arXiv:2009.06242

M. Cerezo, A. Arrasmith, R. Babbush, S. C. Benjamin, S. Endo, K. Fujii, J. R. McClean, K. Mitarai, X. Yuan, L. Cincio, and P. J. Coles,
“Variational Quantum Algorithms” Nature Reviews Physics 3, 625-644 (2021). arXiv:2012.09265

K. Fujii and K. Nakajima,
“Quantum reservoir computing: a reservoir approach toward quantum machine learning on near-term quantum devices”
Reservoir Computing, pp 331-360 (2021). arXiv:2011.04890

M, Negoro, K, Mitarai, K, Nakajima, and K, Fujii,
“Toward NMR Quantum Reservoir Computing” Reservoir Computing, pp 451-458 (2021)

N. Guo, K. Mitarai, and K. Fujii,
“Nonlinear transformation of complex amplitudes via quantum singular value transformation” arXiv:2107.10764

S. Ghosh, K. Nakajima, T. Krisnanda, K. Fujii, and T. C. H. Liew,
“Quantum Neuromorphic Computing with Reservoir Computing Networks” Advanced Quantum Technologies 4, 2100053 (2021)

S. Hakkaku and K. Fujii,
“Comparative study for sampling-based simulation costs of noisy quantum circuits” Phys. Rev. A 15, 064027 (2021). arXiv:2011.06233

T. Kusumoto, K. MitaraiK. Fujii, M. Kitagawa, and M. Negoro,
“Experimental quantum kernel machine learning with nuclear spins in a solid” npj Quantum Information 7, 94 (2021). arXiv:1911.12021

K. Ito, W. Mizukami, and K. Fujii,
“Universal noise-precision relations in variational quantum algorithms” arXiv:2106.03390

K. Kubo, Y. O. Nakagawa, S. Endo, and S. Nagayama,
“Variational quantum simulations of stochastic differential equations” Phys. Rev. A 103, 052425 (2021). arXiv:2012.04429

Y. Takaki, K. Mitarai, M. Negoro, K. Fujii, and M. Kitagawa,
“Learning temporal data with variational quantum recurrent neural network” Phys. Rev. A 103, 52414 (2021). arXiv:2012.11242

2020年

R. Suzuki, K. Mitarai, and K. Fujii,
“Computational power of one- and two-dimensional dual-unitary quantum circuits” arXiv:2103.09211

K. Mitarai and K. Fujii,
“Constructing a virtual two-qubit gate by sampling single-qubit operations” New Journal of Physics 23, 023021 (2020). arXiv:1909.07534

K. Mitarai and K. Fujii,
“Overhead for simulating a non-local channel with local channels by quasiprobability sampling” Quantum 5, 388 (2020). arXiv:2006.11174v2

K. Endo, T. Nakamura, K. Fujii, and N. Yamamoto,
“Quantum self-learning Monte Carlo and quantum-inspired Fourier transform sampler ” Phys. Rev. Research 2, 043442 (2020). arXiv:2005.14075

N. Yoshioka, Y. O. Nakagawa, K. Mitarai, and K. Fujii,
“Variational quantum algorithm for nonequilibrium steady states” Phys. Rev. Research 2, 043289 (2020). arXiv:1908.09836

Y. Suzuki, Y. Kawase, Y. Masumura, Y. Hiraga, M. Nakadai, J. Chen, K. M. Nakanishi, K. Mitarai, R. Imai, S. Tamiya, T. Yamamoto, T. Yan, T. Kawakubo, Y. O. Nakagawa, Y. Ibe, Y. Zhang, H. Yamashita, H. Yoshimura, A. Hayashi, and K. Fujii,
“Qulacs: a fast and versatile quantum circuit simulator for research purpose” arXiv:2011.13524

K. Mitarai, Y. Suzuki, W. Mizukami, Y. O. Nakagawa, and K. Fujii,
“Quadratic Clifford expansion for efficient benchmarking and initialization of variational quantum algorithms” arXiv:2011.09927

K. M. Nakanishi, K. Fujii, and S. Todo,
“Sequential minimal optimization for quantum-classical hybrid algorithms” Phys. Rev. Research 2, 043158 (2020). arXiv:1903.12166

Y. Suzuki, S. Endo, K. Fujii, and Y. Tokunaga,
“Quantum error mitigation for fault-tolerant quantum computing” arXiv:2010.03887

A. Davaasuren, Y. Suzuki, K. Fujii, and M. Koashi,
“General framework for constructing fast and near-optimal machine-learning-based decoder of the topological stabilizer codes”  Phys. Rev. Research 2, 033399 (2020). arXiv:1801.04377

A. Kutvonen, T. Sagawa, and K. Fujii,
“Optimizing a quantum reservoir computer for time series prediction” Scientific Reports 10,14687 (2020). arXiv:1807.03947

K. FujiiK. Mitarai, W. Mizukami, and Y. O. Nakagawa,
“Deep Variational Quantum Eigensolver: a divide-and-conquer method for solving a larger problem with smaller size quantum computers” arXiv:2007.10917

K. Mitarai and K. Fujii,
“Overhead of the non-local-to-local channel decomposition by quasiprobability sampling” arXiv:2006.11174

K. Endo, T. Nakamura, K. Fujii, and N. Yamamoto,
“Quantum self-learning Monte Carlo with quantum Fourier transform sampler” arXiv:2005.14075

2019年

K. Nakajima, K. Fujii, M. Negoro, K. Mitarai, and M. Kitagawa,
“Boosting computational power through spatial multiplexing in quantum reservoir computing” Phys. Rev. A 11, 034021 (2019)arXiv:1803.04574

K. M. Nakanishi, K. Mitarai, and K. Fujii,
“Subspace-search  variational quantum eigensolver for excited states” Phys. Rev. Research 1, 033062 (2019). arXiv:1810.09434

K. Mitarai, M. Kitagawa, and K. Fujii,
“Quantum analog-digital conversion” Phys. Rev. A 99, 012301 (2019). arXiv:1805.11250

K. Mitarai and K. Fujii,
“Methodology for replacing indirect measurements with direct measurements” Phys. Rev. Research 1, 013006 (2019). arXiv:1901.00015

K. Heya, K. M. Nakanishi, K. Mitarai, and K. Fujii,
“Subspace Variational Quantum Simulator” arXiv:1904.08566

K. Mitarai, T. Yan, and K. Fujii,
“Generalization of the output of variational quantum eigensolver by parameter interpolation with low-depth ansatz” Phys. Rev. A 11, 044087 (2019). arXiv:1810.04482

2018年

T. Furuta, K. Fujii, K. Nakajima, S. Tsunegi, H. Kubota, Y. Suzuki, and S. Miwa,
“Macromagnetic simulation for reservoir computing utilizing spin-dynamics in magnetic tunnel junctions” Phys. Rev. A 10, 034063 (2018). arXiv:1805.09977

K. Mitarai, M. Negoro, M. Kitagawa, and K. Fujii,
“Quantum Circuit Learning” Phys. Rev. A 98, 032309 (2018). arXiv:1803.00745

K. Fukui, A. Tomita, A. Okamoto, and K. Fujii,
“High-Threshold Fault-Tolerant Quantum Computation with Analog Quantum Error Correction” Phys. Rev. X 8, 021054 (2018). arXiv:1712.00294

K. Fujii, H. Kobayashi, T. Morimae, H. Nishimura, S. Tamate, and S. Tani,
“Impossibility of Classically Simulating One-Clean-Qubit Model with Multiplicative Error” Phys. Rev. Lett. 120, 200502 (2018). arXiv:1409.6777v2

K. Heya, Y. Suzuki, Y. Nakamura, and K. Fujii,
“Variational Quantum Gate Optimization”. arXiv:1810.12745

M. Negoro, K. Mitarai, K. Fujii, K. Nakajima, and M. Kitagawa,
“Machine learning with controllable quantum dynamics of a nuclear spin ensemble in a solid” arXiv:1806.10910

K. Fujii,
“Quantum speedup in stoquastic adiabatic quantum computation” arXiv:1803.09954

2017年

K. Fujii and K. Nakajima,
“Harnessing Disordered-Ensemble Quantum Dynamics for Machine Learning” Phys. Rev. A 8, 024030 (2017). arXiv:1602.08159

K. Fujii and M. Hayashi,
“Verifiable fault-tolerance in measurement-based quantum computation” Phys. Rev. A 96, 030301R (2017). arXiv:1610.05216

T. Morimae, K. Fujii, and H. Nishimura,
“Power of one nonclean qubit” Phys. Rev. Applied 95, 042336 (2017). arXiv:1610.07244

Y. Suzuki, K. Fujii, and M. Koashi,
“Efficient simulation of quantum error correction under coherent error based on non-unitary free-fermionic formalism” Phys. Rev. Lett. 119, 190503 (2017). arXiv:1703.03671

K. Fujii and T. Morimae,
“Quantum Commuting Circuits and Complexity of Ising Partition Functions“ New J. Phys. 19, 033003 (2017). arXiv:1311.2128

2016年

K. Fujii, H. Kobayashi, T. Morimae, H. Nishimura, S. Tamate, S. Tani (alphabetical order)
“Power of Quantum Computation with Few Clean Qubits”
Proceedings of 43rd International Colloquium on Automata, Languages, and Programming (ICALP 2016), pp. 13:1-13:14. arXiv:1509.07276

Y. Takeuchi, K. Fujii, R. Ikuta, T. Yamamoto, and N. Imoto,
“Blind quantum computation over a collective-noise channel”Phys. Rev. A 93, 052307 (2016).  arXiv:1505.04248

K. Fujii and S. Tamate,
“Computational quantum-classical boundary of commuting quantum circuits” Scientific Reports 6, 25598 (2016). arXiv:1505.04248

K. Fujii,
“Noise Threshold of Quantum Supremacy” arXiv:1610.03632

T. Morimae, K. Fujii, and H. Nishimura,
“Quantum Merlin-Arthur with noisy channel” arXiv:1608.04829

Y. Takeuchi, K. Fujii, T. Morimae, and N. Imoto,
“Fault-tolerant verifiable blind quantum computing with logical state remote preparation”  arXiv:1607.01568

2015年以前

T. Morimae, M. Hayashi, H. Nishimura, and K. Fujii,
“Quantum Merlin-Arthur with Clifford Arthur” Quantum Information and Computation 15, pp1420-1430 (2015).
arXiv:1506.06447

K. Fujii, M. Negoro, N. Imoto, and M. Kitagawa,
“Measurement-Free Topological Protection Using Dissipative Feedback” Phys. Rev. X 4, 041039 (2014).  arXiv:1401.6350

A. Matsuo, K. Fujii, and N. Imoto,
“Quantum algorithm for an additive approximation of Ising partition functions” Phys. Rev. A 90, 022304 (2014). arXiv:1405.2749

T. Morimae, K. Fujii and J. F Fitzsimons,
“Hardness of classically simulating the one-clean-qubit model”
Phys. Rev. Lett. 112, 130502 (2014). arXiv:1312.2496

T. Morimae and K. Fujii,
“Secure entanglement distillation for double-server blind quantum computation” Phys. Rev. Lett. 111, 020502 (2013)arXiv:1302.3786

K. Fujii, 
“Quantum information and statistical mechanics: an introduction to frontier” Interdisciplinary Information Sciences 19, 1-15 (2013)arXiv:1306.6757

T. Morimae and K. Fujii, 
“Blind quantum computation protocol in which Alice only makes measurements” Phys. Rev. A 87, 050301(R) (2013). arXiv:1201.3966

K. Fujii, Y. Nakata, M. Ohzeki, and M. Murao,
“Measurement-Based Quantum Computation on Symmetry Breaking Thermal States” (selected to Editors’ suggestion)
Phys. Rev. Lett. 110, 120502 (2013). arXiv:1209.1265 

M. Ohzeki and K. Fujii,
“Duality analysis on random planar lattice”
Phys. Rev. E 86, 051121 (2012). arXiv:1209.3500

T. Morimae and K. Fujii, 
“Blind topological measurement-based quantum computation”
Nature Communications 3, 1036 (2012).  arXiv:1110.5460

K. Fujii and Y. Tokunaga,
“Error- and Loss-Tolerances of Surface Codes with General Lattice Structures” Phys. Rev. A 86, 020303(R) (2012).  arXiv:1202.2743

T. Morimae and K. Fujii, 
“Not all physical errors can be linear CPTP maps in a correlation space” Scientific Reports 2, 508 (2012).  arXiv:1106.3720  arXiv:1110.4182(supplemental material)

K. Fujii and T.Morimae,
“Computational Power and Correlation in Quantum Computational Tensor Network” Phys. Rev. A 85, 032338 (2012). arXiv:1106.3377

K. Fujii and T. Morimae,
“Topologically protected measurement-based quantum computation on the thermal state of a nearest-neighbor two-body Hamiltonian with spin-3/2 particles”
Phys. Rev. A 85, 010304(R) (2012). arXiv:1111.0919

K. Fujii, T. Yamamoto, M. Koashi, and N. Imoto“A distributed architecture for scalable quantum computation with realistically noisy devices”arXiv:1202.6588

K. Fujii, H. Maeda and K. Yamamoto,
“Robust and Scalable Scheme to Generate Large-Scale Entanglement Webs”
Phys. Rev. A 83, 050303(R) (2011). arXiv:1102.4682

K. Fujii and Y. Tokunaga
” Fault-Tolerant Topological One-Way Quantum Computation with Probabilistic Two-Qubit Gates”
Phys. Rev. Lett. 105, 250503 (2010). arXiv:1008.3752

K. Fujii and K. Yamamoto,
“Topological One-Way Quantum Computation on Verified Logical Cluster States”
Phys. Rev. A 82, 060301(R) (2010).  arXiv:1008.2048

K. Fujii and K. Yamamoto,
“Anti-Zeno effect for quantum transport in disordered systems”
Phys. Rev. A 82, 042109 (2010).  arXiv:1003.1804

K. Fujii and K. Yamamoto
“Cluster-based architecture for fault-tolerant quantum computation”
Phys. Rev. A 81, 042324 (2010).  arXiv:0912.5150

K. Fujii and K. Yamamoto,
“Entanglement purification with double-selection”
Phys. Rev. A 80, 042308 (2009).  arXiv:0811.2639

■ 国際会議プロシーディング

K. Fujii and K. Yamamoto“Fault-tolerant quantum computation in concatenation of verified cluster states”, Proceedings of the 9th International Conference of QCMC (AIP Press, Melville, NY, 2009), p. 141.
arXiv:0802.4137

K. Fujii and K. Yamamoto“Robust One-Way Computer using Encoded Qubits”,
Proceedings of the 8th International Conference of QCMC (NICT Press, 2007), p. 105.
arXiv:quant-ph/0611160

K. Fujii, T. Yamamoto, M. Koashi and N. Imoto”Fault-tolerant quantum computation and communication on a distributed 2D array of small local systems”,
AIP Conf. Proc. 1633, 153 (2014)

Y. Tokunaga and K. Fujii ,“Thresholds of surface codes on the general lattice structures suffering biased error and loss”,
AIP Conf. Proc. 1633, 198 (2014) 

■ 書籍

K. Fujii, “Quantum Computation with Topological Codes: from qubit to topological fault-tolerance” Springer- Briefs in Mathematical Physics vol. 8 (Springer-Verlag 2015).
arXiv:1504.01444

Keisuke Fujii “TOPOLOGICAL PROTECTION OF QUANTUM INFORMATION”
in Kinki University Series on Quantum Computing – Vol. 9 “Physics, Mathematics, and All that Quantum Jazz”