7 papers
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…
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…
Quantum walk with a local spin interaction
Manami Yamagishi, Naomichi Hatano, Kohei Kawabata +4
We introduce a model of quantum walkers interacting with a magnetic impurity localized at the origin. First, we study a model of a single quantum walker interacting with a localize…
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…
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…