11 citations · 32 across the 17 of their papers we have counts for
9 papers · 1 filter
Chern-number estimation: nearly optimal quantum algorithm and provable quantum speedup
Soichiro Imamura, Shintaro Ae, Kazuki Sakamoto +2
Topological phases of matter are characterized by global properties of quantum states beyond conventional local order parameters. The Chern number is a central invariant in this ch…
Structure-Aware Variance Reduction for Unbiased Randomized Hamiltonian Simulation
Joshua W. Dai, Fredrik Hasselgren, Chusei Kiumi
Randomized Hamiltonian simulation methods are often governed by a trade-off between systematic bias and sampling overhead. We study how classical variance-reduction techniques can…
Adiabatic Error Cancellation in Berry Phase Estimation
Chusei Kiumi
The Berry phase encodes the geometry of a closed Hamiltonian path, complementing the dynamical phase determined by the accumulated energy. We uncover an adiabatic error-cancellatio…
Introducing a Kondo-type interaction to the model of quantum walkers
Manami Yamagishi, Naomichi Hatano, Kohei Kawabata +4
We introduce a model of discrete-time quantum walkers interacting with a lozalized magnetic impurity. Each quantum walker interacts with an impurity, through which multiple quantum…
Low-Resource Quantum Energy Gap Estimation via Randomization
Hugo Pages, Chusei Kiumi, Yuto Morohoshi +2
Estimating the energy spectra of quantum many-body systems is a fundamental task in quantum physics, with applications ranging from chemistry to condensed matter. Algorithmic shado…
Computational complexity of Berry phase estimation in topological phases of matter
Ryu Hayakawa, Kazuki Sakamoto, Chusei Kiumi
The Berry phase is a fundamental quantity in the classification of topological phases of matter. In this paper, we present a new quantum algorithm and several complexity-theoretica…
TE-PAI: Exact Time Evolution by Sampling Random Circuits
Chusei Kiumi, Bálint Koczor
Simulating time evolution under quantum Hamiltonians is one of the most natural applications of quantum computers. We introduce TE-PAI, which simulates time evolution exactly by sa…
Operator quantum singular value transformation: Spectral mapping, design and topological invariants
Chusei Kiumi, Akito Suzuki, Yohei Tanaka
Quantum singular value transformation (QSVT) provides a unifying framework for quantum algorithms by applying the polynomials of quantum signal processing (QSP) to block-encoded ma…
Spectral analysis of three-state quantum walks with general coin matrices
Chusei Kiumi, Jirô Akahori, Takuya Watanabe +1
Mathematical analysis of the spectral properties of the time evolution operator in quantum walks is essential for understanding key dynamical behaviors such as localization and lon…