arXiv subjects

Naoya Ozawa

Publications and source records attributed to Naoya Ozawa.

4 recordsLinked to original sources

arXiv2026

Detecting dark matter using optically trapped Rydberg atom tweezer arrays

A new scheme for detecting wave-like dark matter (DM) using Rydberg atoms is proposed. Recent advances in trapping and manipulating Rydberg atoms make it possible to use Rydberg atoms trapped in optical tweezer arrays for DM detection. We propose to prepare a large ensemble of Rydberg atoms and to observe the excitations between Rydberg states by the DM-induced effective electric field. A scan over DM mass is enabled with the use of the Zeeman and diamagnetic shifts of energy levels under an applied external magnetic field. Taking dark-photon DM as an example, we demonstrate that our proposed experiment can have high enough sensitivity to probe previously unexplored regions of the parameter space of dark-photon coupling strengths and masses.

hep-ph↗

arXiv2025

Plane-selective manipulations of nuclear spin qubits in a three-dimensional optical tweezer array

One of the central challenges for a practical fault-tolerant quantum computer is scalability. A three-dimensional structure of optical tweezer arrays offers the potential for scaling up neutral atom processors. However, coherent local operations, essential for quantum error correction, have yet to be explored for this platform. Here, we demonstrate plane-by-plane initialization of nuclear spin qubits of ${}^{171}\mathrm{Yb}$ atoms in a three-dimensional atom array and plane-dependent coherent temporal evolution of qubits, as well as plane-selective qubit manipulation by exploiting the plane-selective excitation of the atoms from the ${}^1S_0$ to the ${}^3P_2$ state. This plane-selective manipulation technique paves the way for quantum computing and quantum simulation in three-dimensional multilayer architectures.

quant-ph↗

arXiv2024

Development of a high-power ultraviolet laser system and observation of fast coherent Rydberg excitation of ytterbium

We present the development of a high-power ultraviolet laser system operating at a wavelength of 325 nm for Rydberg excitation from the ${}^3\mathrm{P}_2$ state of ytterbium. Utilizing a two-stage frequency doubling scheme, we achieved an output power exceeding 800 mW. The system effectively suppresses frequency noise in the MHz range, which is critical for achieving high Rydberg excitation fidelity, through the use of a filtering cavity. Using this system, we demonstrated coherent excitation of the $(6s71s){}^3\mathrm{S}_1$ Rydberg state with a Rabi frequency of 2.13(3) MHz. Combined with our successful manipulations on the ${}^1\mathrm{S}_0-{}^3\mathrm{P}_2$ transition, this work represents a foundational step toward achieving high-fidelity Rydberg excitation, enabling advancements in quantum simulation and computing with neutral atom arrays.

physics.atom-ph↗

arXiv2024

A hybrid atom tweezer array of nuclear spin and optical clock qubits

While data qubits with a long coherence time are essential for the storage of quantum information, ancilla qubits are pivotal in quantum error correction (QEC) for fault-tolerant quantum computing. The recent development of optical tweezer arrays, such as the preparation of large-scale qubit arrays and high-fidelity gate operations, offers the potential for realizing QEC protocols, and one of the important next challenges is to control and detect ancilla qubits while minimizing atom loss and crosstalk. Here, we present the realization of a hybrid system consisting of a dual-isotope ytterbium (Yb) atom array, in which we can utilize a nuclear spin qubit of fermionic ${}^{171}\mathrm{Yb}$ as a data qubit and an optical clock qubit of bosonic ${}^{174}\mathrm{Yb}$ as an ancilla qubit with a capacity of non-destructive qubit readout. We evaluate the crosstalk between qubits regarding the impact on the coherence of the nuclear spin qubits from the imaging light for ${}^{174}\mathrm{Yb}$. The Hahn-echo sequence with a 399 nm probe and 556 nm cooling beams for ${}^{174}\mathrm{Yb}$, we observe 99.1(1.8) % coherence retained under 20 ms exposure, yielding an imaging fidelity of 0.9992 and a survival probability of 0.988. The Ramsey sequence with a 556 nm probe beam shows negligible influence on the coherence, suggesting the potential future improvement of low cross-talk measurements. This result highlights the potential of the hybrid-Yb atom array for ancilla-qubit-based QEC protocols.

quant-ph↗