Squeezed Josephson plasmons in driven YBa$_2$Cu$_3$O$_{6+x}$

N. Taherian; M. Först; A. Liu; M. Fechner; D. Pavicevic; A. von Hoegen; E. Rowe; Y. Liu; S. Nakata; B. Keimer; E. Demler; M. H. Michael; A. Cavalleri

doi:10.1038/s41535-025-00776-1

paper

Squeezed Josephson plasmons in driven YBa $_{2}$ Cu $_{3}$ O $_{6 + x}$

arXiv:2401.01115 · doi:10.1038/s41535-025-00776-1

Abstract

The physics of driven collective modes in quantum materials underpin a number of striking non-equilibrium functional responses, which include enhanced magnetism, ferroelectricity and superconductivity. However, the coherent coupling between multiple modes at once are difficult to capture by single-pump probe (one-dimensional) spectroscopy, and often remain poorly understood. One example is phonon-mediated amplification of Josephson plasmons in YBa $_{2}$ Cu $_{3}$ O $_{6 + x}$ , in which at least three normal modes of the solid are coherently mixed as a source of enhanced superconductivity. Here, we go beyond previous pump-probe experiments in this system and acquire two-dimensional frequency maps using pairs of mutually delayed, carrier envelope phase stable mid-infrared pump pulses, combined with measurements of the time-modulated second-order nonlinear optical susceptibility. We find that the driven zone-center phonons amplify coherent pairs of opposite-momentum Josephson plasma polaritons, generating a squeezed state of interlayer phase fluctuations. The squeezed state is a potentially important ingredient in the microscopic physics of photo-induced superconductivity in this and other materials.

arXiv comment20 pages, 7 figures

Squeezed Josephson plasmons in driven YBa $_{2}$ Cu $_{3}$ O $_{6 + x}$

Abstract

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Squeezed Josephson plasmons in driven YBa2​Cu3​O6+x​

Abstract

References in corpus (49)

Cited by in corpus (6)

Squeezed Josephson plasmons in driven YBa $_{2}$ Cu $_{3}$ O $_{6 + x}$