arXiv subjects

Naoki Yoshioka

Publications and source records attributed to Naoki Yoshioka.

6 recordsLinked to original sources

arXiv2026

Axionic Wormholes in Metric-Affine Gravity

The axion is a promising candidate for solving the strong CP problem. To solve this problem, the global U(1) symmetry must be preserved to a high degree of accuracy. However, it is well known that global symmetries are explicitly violated by quantum gravity effects, giving rise to what is referred to as the axion quality problem. In this paper, we investigate axionic wormholes as a source of explicit U(1) violation in Metric-Affine Gravity. This framework allows for spacetime torsion and non-metricity, which accommodate additional curvature-like and topological terms, such as the Holst and Nieh--Yan terms, that are absent from the metric and Palatini formalisms. We show that non-minimal couplings to these terms modify the wormhole dynamics and enhance the Euclidean wormhole action, thereby alleviating the axion quality problem. We also find that the viable parameter space is enlarged when two of these couplings are simultaneously present. We further identify representative parameter regions where the alleviation of the axion quality problem is compatible with inflationary constraints.

hep-ph↗

arXiv2025

A Closeness Centrality-based Circuit Partitioner for Quantum Simulations

Simulating quantum circuits (QC) on high-performance computing (HPC) systems has become an essential method to benchmark algorithms and probe the potential of large-scale quantum computation despite the limitations of current quantum hardware. However, these simulations often require large amounts of resources, necessitating the use of large clusters with thousands of compute nodes and large memory footprints. In this work, we introduce an end-to-end framework that provides an efficient partitioning scheme for large-scale QCs alongside a flexible code generator to offer a portable solution that minimizes data movement between compute nodes. By formulating the distribution of quantum states and circuits as a graph problem, we apply closeness centrality to assess gate importance and design a fast, scalable partitioning method. The resulting partitions are compiled into highly optimized codes that run seamlessly on a wide range of supercomputers, providing critical insights into the performance and scalability of quantum algorithm simulations.

quant-ph↗

arXiv2025

Advantages of Co-locating Quantum-HPC Platforms: A Survey for Near-Future Industrial Applications

We conducted a systematic survey of emerging quantum-HPC platforms, which integrate quantum computers and High-Performance Computing (HPC) systems through co-location. Currently, it remains unclear whether such platforms provide tangible benefits for near-future industrial applications. To address this, we examined the impact of co-location on latency reduction, bandwidth enhancement, and advanced job scheduling. Additionally, we assessed how HPC-level capabilities could enhance hybrid algorithm performance, support large-scale error mitigation, and facilitate complex quantum circuit partitioning and optimization. Our findings demonstrate that co-locating quantum and HPC systems can yield measurable improvements in overall hybrid job throughput. We also observe that large-scale real-world problems can require HPC-level computational resources for executing hybrid algorithms.

quant-ph↗

arXiv2024

Non-thermal particle production in Einstein-Cartan gravity with modified Holst term and non-minimal couplings

Non-thermal fermionic particle production is investigated in Einstein-Cartan modified gravity with a modified Holst term and non-minimal couplings between the spin connection and a fermion. By using the auxiliary field method, the theory is rewritten into a pseudoscalar-tensor theory with Einstein-Hilbert action and canonical kinetic and potential terms for a pseudoscalar field. The introduced field is called Einstein-Cartan pseudoscalaron. If the potential energy of the Einstein-Cartan pseudoscalaron dominates the energy density of the early universe, it causes inflationary expansion. After the end of inflation, the pseudoscalaron develops a large value and the non-minimal couplings destabilize the vacuum. Evaluating the non-thermal fermionic particle production process, we obtain the mass and the helicity dependences of the produced particle number density. We show the model parameters to enhance the preheating and reheating processes.

gr-qc↗

arXiv2018

Massively parallel quantum computer simulator, eleven years later

A revised version of the massively parallel simulator of a universal quantum computer, described in this journal eleven years ago, is used to benchmark various gate-based quantum algorithms on some of the most powerful supercomputers that exist today. Adaptive encoding of the wave function reduces the memory requirement by a factor of eight, making it possible to simulate universal quantum computers with up to 48 qubits on the Sunway TaihuLight and on the K computer. The simulator exhibits close-to-ideal weak-scaling behavior on the Sunway TaihuLight,on the K computer, on an IBM Blue Gene/Q, and on Intel Xeon based clusters, implying that the combination of parallelization and hardware can track the exponential scaling due to the increasing number of qubits. Results of executing simple quantum circuits and Shor's factorization algorithm on quantum computers containing up to 48 qubits are presented.

quant-ph↗

arXiv2012

Phase transition in peristaltic transport of frictionless granular particles

Flow of dissipative particles driven by peristaltic motion of a tube is numerically studied. A transition from slow unjammed flow to fast jammed flow is found through the observation of the mass flux if the minimum width of the peristaltic tube is smaller than a critical value. It is also found that average and fluctuation of the transition time, and the peak value of the second moment of the mass flux exhibit power-law divergences at the critical point and these variables satisfy scaling relationships near the critical point. Dependences of the critical width and exponents on peristaltic velocity and on density are also discussed.

cond-mat.soft↗