arXiv subjects

Genji Fujii

Publications and source records attributed to Genji Fujii.

3 recordsLinked to original sources

arXiv2026

Universality in Terms of The BECs Bloch-Sphere Manipulations

Quantum computing promises to outperform classical computing for certain computational tasks. One of the key concepts underlying this potential is universality. Universality has been extensively studied not only for qubits but also for higher-dimensional quantum systems, such as qutrits and qudits, which span Hilbert spaces of dimension greater than two. However, the concept of universality in Bose-Einstein condensates (BECs) qubit systems, which have been proposed relatively recently, remains insufficiently understood. In this work, we analyzed universality in BECs qubit systems. Our results clarify the theoretical aspects of universality in quantum computation within the class of ((N+1))-dimensional representations of SU(2), taking into account two distinct representations of the quantum states.

quant-ph↗

arXiv2025

Measurement-based quantum computation using two-component BECs

In this paper, we propose measurement-based quantum computation (MBQC) using two-component Bose-Einstein condensates (BECs). Graph states are naturally introduced by analogy with the qubit case. An arbitrary state of one logical qubit can be obtained through a three-body measurement. Furthermore, we propose methods for implementing CZ gates on the components of coherent states of BECs in a graph state, as well as CZ gates on logical qubits. A distinctive feature of our approach is that the post-measurement state is shown to depend on the particle number. These results suggest a novel quantum computing process based on particle control.

quant-ph↗

arXiv2025

Measurement-based quantum computation utilizing the graph states of Bose-Einstein condensates and continuous variables

Measurement-based quantum computation (MBQC) is a protocol for quantum computation that represents a model distinct from the circuit-based approach. MBQC has been proposed not only for qubits but also for qudits, continuous-variable (CV) qubits, and Bose-Einstein condensates (BECs) qubits. In qubit-based MBQC, arbitrary rotations on the Bloch sphere can be performed by measuring a graph state. This naturally raises the question of whether arbitrary rotations on the Bloch sphere can similarly be achieved through measurements in other types of quantum bits. We have demonstrated that this can indeed be realized for BECs qubits by considering composite graph states involving CV qubits and BECs qubits.

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