318 citations · 1.5k across the 48 of their papers we have counts for
48 papers
Mirror subspace diagonalization: A real-time quantum Krylov algorithm with near-optimal sampling cost
Shota Kanasugi, Yuya O. Nakagawa, Norifumi Matsumoto +3
Quantum Krylov algorithms are a promising approach for ground-state energy estimation on near-term quantum computers. However, their sampling cost is inherently high because each H…
Application of resource theory based on free Clifford+kT computation to early fault-tolerant quantum computing
Yuya O. Nakagawa, Yasunori Lee
Recent advances in quantum hardware are bringing fault-tolerant quantum computing (FTQC) closer to reality. In the early stage of FTQC, however, the numbers of available logical qu…
Non-Hermitian Quantum Many-Body Scar Phase
Keita Omiya, Yuya O Nakagawa
We introduce a novel non-equilibrium phase -- the quantum many-body scar (QMBS) phase -- that emerges in non-Hermitian many-body dynamics when scarred wavefunctions are selectively…
Quantum expectation value estimation by doubling the number of qubits
Hiroshi Yano, Masaya Kohda, Shoichiro Tsutsui +4
Expectation value estimation is ubiquitous in quantum algorithms. The expectation value of a Hamiltonian, which is essential in various practical applications, is often estimated b…
Quantum-selected configuration interaction with time-evolved state
Mathias Mikkelsen, Yuya O. Nakagawa
Quantum-selected configuration interaction (QSCI) utilizes an input quantum state on a quantum device to select important bases (electron configurations in quantum chemistry) that…
Quantum many-body simulation of finite-temperature systems with sampling a series expansion of a quantum imaginary-time evolution
Norifumi Matsumoto, Shoichiro Tsutsui, Yuya O. Nakagawa +5
Simulating thermal-equilibrium properties at finite temperature is crucial for studying quantum many-body systems. Quantum computers are expected to enable us to simulate large sys…
Subspace-Based Local Compilation of Variational Quantum Circuits for Large-Scale Quantum Many-Body Simulation
Shota Kanasugi, Yuichiro Hidaka, Yuya O. Nakagawa +5
Simulation of quantum many-body systems is a promising application of quantum computers. However, implementing the time-evolution operator as a quantum circuit efficiently on near-…
ADAPT-QSCI: Adaptive Construction of an Input State for Quantum-Selected Configuration Interaction
Yuya O. Nakagawa, Masahiko Kamoshita, Wataru Mizukami +2
We present a quantum-classical hybrid algorithm for calculating the ground state and its energy of the quantum many-body Hamiltonian by proposing an adaptive construction of a quan…
Classical variational optimization of PREPARE circuit for quantum phase estimation of quantum chemistry Hamiltonians
Hayata Morisaki, Kosuke Mitarai, Keisuke Fujii +1
We propose a method for constructing circuits for quantum phase estimation of a molecular Hamiltonian in quantum chemistry by using variational optimization of q…
Demonstrating Quantum Computation for Quasiparticle Band Structures
Takahiro Ohgoe, Hokuto Iwakiri, Masaya Kohda +4
Understanding and predicting the properties of solid-state materials from first-principles has been a great challenge for decades. Owing to the recent advances in quantum technolog…
Accelerated variational quantum eigensolver with joint Bell measurement
Chenfeng Cao, Hiroshi Yano, Yuya O. Nakagawa
The variational quantum eigensolver (VQE) stands as a prominent quantum-classical hybrid algorithm for near-term quantum computers to obtain the ground states of molecular Hamilton…
Computation of Green's function by local variational quantum compilation
Shota Kanasugi, Shoichiro Tsutsui, Yuya O. Nakagawa +3
Computation of the Green's function is crucial to study the properties of quantum many-body systems such as strongly correlated systems. Although the high-precision calculation of…
Quantum-Selected Configuration Interaction: classical diagonalization of Hamiltonians in subspaces selected by quantum computers
Keita Kanno, Masaya Kohda, Ryosuke Imai +4
We propose quantum-selected configuration interaction (QSCI), a class of hybrid quantum-classical algorithms for calculating the ground- and excited-state energies of many-electron…
Almost optimal measurement scheduling of molecular Hamiltonian via finite projective plane
Wataru Inoue, Koki Aoyama, Yusuke Teranishi +3
We propose an efficient and almost optimal scheme for measuring molecular Hamiltonians in quantum chemistry on quantum computers, which requires distinct measurements in the…
Averaging gate approximation error and performance of Unitary Coupled Cluster ansatz in Pre-FTQC Era
Kohdai Kuroiwa, Yuya O. Nakagawa
Fault-tolerant quantum computation (FTQC) is essential to implement quantum algorithms in a noise-resilient way, and thus to enjoy advantages of quantum computers even with presenc…
Analytical formulation of the second-order derivative of energy for orbital-optimized variational quantum eigensolver: application to polarizability
Yuya O. Nakagawa, Jiabao Chen, Shotaro Sudo +2
We develop a quantum-classical hybrid algorithm to calculate the analytical second-order derivative of the energy for the orbital-optimized variational quantum eigensolver (OO-VQE)…
Local variational quantum compilation of a large-scale Hamiltonian dynamics
Kaoru Mizuta, Yuya O. Nakagawa, Kosuke Mitarai +1
Implementing time evolution operators on quantum circuits is important for quantum simulation. However, the standard way, Trotterization, requires a huge numbers of gates to achiev…
Quantum expectation-value estimation by computational basis sampling
Masaya Kohda, Ryosuke Imai, Keita Kanno +3
Measuring expectation values of observables is an essential ingredient in variational quantum algorithms. A practical obstacle is the necessity of a large number of measurements fo…
Molecular Structure Optimization based on Electrons-Nuclei Quantum Dynamics Computation
Hirotoshi Hirai, Takahiro Horiba, Soichi Shirai +4
A new concept of the molecular structure optimization method based on quantum dynamics computations is presented. Nuclei are treated as quantum mechanical particles, as are electro…
Non-normal Hamiltonian dynamics in quantum systems and its realization on quantum computers
Nobuyuki Okuma, Yuya O. Nakagawa
The eigenspectrum of a non-normal matrix, which does not commute with its Hermitian conjugate, is a central issue of non-Hermitian physics that has been extensively studied in the…
Analytical energy gradient for state-averaged orbital-optimized variational quantum eigensolvers and its application to a photochemical reaction
Keita Omiya, Yuya O. Nakagawa, Sho Koh +3
Elucidating photochemical reactions is vital to understand various biochemical phenomena and develop functional materials such as artificial photosynthesis and organic solar cells,…
Calculating the Green's function of two-site Fermionic Hubbard model in a photonic system
Jie Zhu, Yuya O. Nakagawa, Chuan-Feng Li +2
The Green's function has been an indispensable tool to study many-body systems that remain one of the biggest challenges in modern quantum physics for decades. The complicated calc…
Deep variational quantum eigensolver for excited states and its application to quantum chemistry calculation of periodic materials
Kaoru Mizuta, Mikiya Fujii, Shigeki Fujii +4
A programmable quantum device that has a large number of qubits without fault-tolerance has emerged recently. Variational Quantum Eigensolver (VQE) is one of the most promising way…
Quadratic Clifford expansion for efficient benchmarking and initialization of variational quantum algorithms
Kosuke Mitarai, Yasunari Suzuki, Wataru Mizukami +2
Variational quantum algorithms are considered to be appealing applications of near-term quantum computers. However, it has been unclear whether they can outperform classical algori…