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| Main Authors: | , |
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| Format: | Preprint |
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2025
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| Online Access: | https://arxiv.org/abs/2503.15643 |
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| _version_ | 1866915578235584512 |
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| author | Dzero, Maxim Kamenev, Alex |
| author_facet | Dzero, Maxim Kamenev, Alex |
| contents | Collective modes in superconductors provided the first realization of the Higgs mechanism. The transverse Goldstone mode acquires a gap (i.e. a mass) when it hybridizes with the electromagnetic gauge field. The longitudinal Schmid-Higgs mode, on the other hand, is always massive. In conventional BCS theory, its gap is exactly $2Δ$, coinciding with the excitation threshold for quasiparticles. Being situated right at the edge of the continuum spectrum it gives rise to peculiar dynamics for the Schmid-Higgs mode. For instance, when suddenly excited at $t=0$, it exhibits algebraically decaying oscillations of the form $\sim \sin(2Δt)/{t}^{1/2}$. In this study, we explore the behavior of Schmid-Higgs oscillations in the presence of pair-breaking mechanisms, such as magnetic impurities or in-plane magnetic fields. These processes suppress the quasiparticle excitation threshold down to $2\varepsilon_g < 2Δ$, potentially placing the longitudinal mode within the continuum spectrum. Despite this, we show that the algebraically decaying oscillations persist, taking the form $\sim \sin(2\varepsilon_g t)/t^2$. The Schmid-Higgs mode becomes truly overdamped and exponentially decaying only in the gapless superconductors with $\varepsilon_g=0$. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2503_15643 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Schmid-Higgs Mode in the Presence of Pair-Breaking Interactions Dzero, Maxim Kamenev, Alex Superconductivity Collective modes in superconductors provided the first realization of the Higgs mechanism. The transverse Goldstone mode acquires a gap (i.e. a mass) when it hybridizes with the electromagnetic gauge field. The longitudinal Schmid-Higgs mode, on the other hand, is always massive. In conventional BCS theory, its gap is exactly $2Δ$, coinciding with the excitation threshold for quasiparticles. Being situated right at the edge of the continuum spectrum it gives rise to peculiar dynamics for the Schmid-Higgs mode. For instance, when suddenly excited at $t=0$, it exhibits algebraically decaying oscillations of the form $\sim \sin(2Δt)/{t}^{1/2}$. In this study, we explore the behavior of Schmid-Higgs oscillations in the presence of pair-breaking mechanisms, such as magnetic impurities or in-plane magnetic fields. These processes suppress the quasiparticle excitation threshold down to $2\varepsilon_g < 2Δ$, potentially placing the longitudinal mode within the continuum spectrum. Despite this, we show that the algebraically decaying oscillations persist, taking the form $\sim \sin(2\varepsilon_g t)/t^2$. The Schmid-Higgs mode becomes truly overdamped and exponentially decaying only in the gapless superconductors with $\varepsilon_g=0$. |
| title | Schmid-Higgs Mode in the Presence of Pair-Breaking Interactions |
| topic | Superconductivity |
| url | https://arxiv.org/abs/2503.15643 |