collaborators

5 papers

quant-ph2026

Learning Enables Exponential-to-Polynomial Sampling Overhead Scaling in Quantum Divide-and-Conquer for Tree-Structured Circuits

Hiroyuki Harada, Kaito Wada, Naoki Yamamoto +1

Quantum circuit cutting and knitting are divide-and-conquer methods that enable large-scale quantum computations on hardware with limited qubit resources and connectivity by decomp…

quant-ph2026

Adaptive identification of low-degree polynomials in quantum singular value transformation: application to nonlinear quantum properties estimation

Jumpei Kato, Akira Tanji, Hiroyuki Harada +3

Estimating properties of unknown quantum states via quantum singular value transformation (QSVT) often requires high-degree polynomials to handle small eigenvalues of density matri…

quant-ph2026

Trade-offs between Quantum and Classical Resources in the Linear Combination of Unitaries

Kaito Wada, Hiroyuki Harada, Yasunari Suzuki +3

The randomized linear combination of unitaries (LCU) method with many applications to early fault-tolerant quantum computing algorithms has been proposed. This quantum algorithm co…

quant-ph2025

State-to-Hamiltonian conversion with a few copies

Kaito Wada, Jumpei Kato, Hiroyuki Harada +1

Density matrix exponentiation (DME) is a general procedure that converts an unknown quantum state into the Hamiltonian evolution. This enables state-dependent operations and can re…

quant-ph2025

Density matrix representation of hybrid tensor networks for noisy quantum devices

Hiroyuki Harada, Yasunari Suzuki, Bo Yang +2

The hybrid tensor network (HTN) method is a general framework allowing for the construction of an effective wavefunction with the combination of classical tensors and quantum tenso…