arXiv subjects

Taiju Suzuki

Publications and source records attributed to Taiju Suzuki.

3 recordsLinked to original sources

arXiv2026

Chern-Simons invariants and volumes of representations in Nil, Sol, and Euclidean geometries

In this paper, we realize volumes of representations as real-valued Chern-Simons invariants in Nil, Sol, and Euclidean geometries. To this end, we formulate a Chern-Simons invariant of a pair of connections on a principal bundle that need not be trivial. For a connected closed oriented 3-manifold $M$ and a representation $ρ\colonπ_1(M)\to G$ into the identity component $G$ of the isometry group of one of these geometries, we construct an auxiliary connection on the associated flat $G$-bundle. We show that, for a suitably normalized invariant polynomial, the Chern-Simons invariant of the auxiliary and flat connections equals the volume of the representation. For the holonomy representation of a geometric structure, this invariant recovers the Riemannian volume. We also compute the Chern-Simons invariant of the Levi-Civita connection for representative closed manifolds in each of these geometries.

math.GT↗

arXiv2026

The FLARE Facility

The Facility for Laboratory Reconnection Experiments (FLARE) has been constructed to study magnetic reconnection in multiple X-line regimes relevant to space, astrophysical, and fusion plasmas. Building upon the successful design of the Magnetic Reconnection Experiment (MRX), FLARE features a larger physical volume, stronger magnetic fields, and an independent ohmic heating drive to significantly extend the accessible parameter space, targeting Lundquist numbers up to S ~ 10^5 and normalized system sizes up to λ~ 10^3. This paper details the facility's core engineering components, including the primary vacuum vessel, internal flux cores, highly segmented external coil systems, modular capacitor banks, and the safety interlock and control architecture. An initial diagnostic suite is presented, comprising high-resolution 2D magnetic probe arrays, triple Langmuir probes, a fully fiber-coupled interferometer, ion Doppler spectroscopy, and fast camera imaging. Initial operations demonstrate the device's experimental flexibility and reliability, successfully executing symmetric push-pull reconnection, spheromak merging, and asymmetric downstream configurations. Currently operating within "Stage 2.5" with S ~ 2,500 and λ~ 60 for anti-parallel reconnection, FLARE provides immediate access to the multiple X-line regimes. Planned hardware upgrades, advanced diagnostic additions, and integration with fully kinetic simulations will further expand its capabilities as it transitions into a collaborative user facility for the broader plasma science community.

physics.plasm-ph↗

arXiv2021

Integrated near-field thermophotovoltaic device overcoming far-field blackbody limit

Near-field thermal radiation transfer overcoming the far-field blackbody limit has attracted significant attention in recent years owing to its potential for drastically increasing the output power and conversion efficiency of thermophotovoltaic (TPV) power generation systems. Here, we experimentally demonstrate a one-chip near-field TPV device overcoming the far-field blackbody limit, which integrates a 20-um-thick Si emitter and an InGaAs PV cell with a sub-wavelength gap (<140 nm). The device exhibits a photocurrent density of 1.49 A/cm2 at 1192 K, which is 1.5 times larger than the far-field limit at the same temperature. In addition, we obtain an output power of 1.92 mW and a system efficiency of 0.7% for a 1-mm2 device, both of which are one to two orders of magnitude greater than those of the previously reported near-field systems. Detailed comparisons between the simulations and experiments reveal the possibility of a system efficiency of >35% in the up-scaled device, thus demonstrating the potential of our integrated near-field TPV device for practical use in the future.

physics.app-ph↗