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arXiv · 2606.18563

Time-resolved synchronization analysis of stacked intrinsic Josephson junctions of a cuprate superconductor with frequency-modulated terahertz radiation spectra

Masashi Miyamoto·Keisuke Mizoguchi·Ryota Kobayashi·Nozomi Yagyu·Manabu Tsujimoto·Itsuhiro Kakeya
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Abstract

Terahertz radiation from $\text{Bi}_2\text{Sr}_2\text{CaCu}_2\text{O}_{8+\delta}$ intrinsic Josephson junctions (IJJs) provides an ideal platform to study the synchronization of a macroscopic quantum system. Here, we present a spectral analysis of a frequency-modulated Josephson plasma emitter coupled with patch antennas. In the unmodulated intensity distribution as a function of radiation frequency $I_{\mathrm{UM}}(\omega)$, we observe a double Gaussian peak structure. Crucially, double-peak spectra obtained at a constant bias voltage imply either a rapid temporal distribution of resonances or their simultaneous excitation, driven by the mutual electromagnetic coupling between the IJJ mesa and the antennas. At low modulation frequencies $f_m$, the spectra are well reproduced by the products of $I_{\mathrm{UM}}(\omega)$ and frequency combs, yielding a synchronized relaxation time $\tau_s \simeq 0.28\text{ ns}$. Incorporating $\tau_s$ quantitatively reproduces a drastic spectral transformation observed around $f_m \sim 1\text{ GHz}$, unveiling the sub-nanosecond non-equilibrium dynamics of coupled Josephson plasma.

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Masashi Miyamoto, Keisuke Mizoguchi, Ryota Kobayashi, Nozomi Yagyu, Manabu Tsujimoto, Itsuhiro Kakeya. 2026-06-17. Time-resolved synchronization analysis of stacked intrinsic Josephson junctions of a cuprate superconductor with frequency-modulated terahertz radiation spectra. https://arxiv.org/abs/2606.18563

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