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arXiv · 2310.08162

Direct observation of the Higgs particle in a superconductor by non-equilibrium Raman scattering

Tomke E. Glier·Sida Tian·Mika Rerrer·Lea Westphal·Garret Lüllau·Liwen Feng·Jakob Dolgner·Rafael Haenel·Marta Zonno·Hiroshi Eisaki·Martin Greven·Andrea Damascelli·Stefan Kaiser·Dirk Manske·Michael Rübhausen
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Abstract

Even before its role in electroweak symmetry breaking, the Anderson-Higgs mechanism was introduced to explain the Meissner effect in superconductors. Spontaneous symmetry-breaking yields massless phase modes representing the low-energy excitations of the Mexican-Hat potential. Only in superconductors the phase mode is shifted towards higher energies owing to the gauge field of the charged condensate. This results in a low-energy excitation spectrum governed by the Higgs mode. Consequently, the Meissner effect signifies a macroscopic quantum condensate in which a photon acquires mass, representing a one-to-one analogy to high-energy physics. We report on the direct observation of the Higgs particle in the high-temperature superconductor Bi-2212 by developing an innovative technique to study its symmetries and energies after a "soft quench" of the Mexican-Hat potential. Population inversion of the metastable Higgs particle induced by an initial laser pulse allows identifying the polarization-dependent Higgs modes as an additional anti-Stokes Raman-scattering signal. Within Ginzburg-Landau theory, the Higgs-mode energy is connected to the Cooper-pair coherence length. Within a BCS weak-coupling model we develop a quantitative and coherent description of single-particle and two-particle channels. This opens the avenue for Higgs Spectroscopy in quantum condensates and provides a unique pathway to control and explore Higgs physics.

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Tomke E. Glier, Sida Tian, Mika Rerrer, Lea Westphal, Garret Lüllau, Liwen Feng, Jakob Dolgner, Rafael Haenel, Marta Zonno, Hiroshi Eisaki, Martin Greven, Andrea Damascelli, Stefan Kaiser, Dirk Manske, Michael Rübhausen. 2023-10-12. Direct observation of the Higgs particle in a superconductor by non-equilibrium Raman scattering. https://doi.org/10.1038/s41467-025-62245-4

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