Direct observation of the quantum fluctuation driven amplitude mode in a microcavity polariton condensate

Mark Steger, Ryo Hanai, Alexander Orson Edelman, Peter B. Littlewood, David W. Snoke, Jonathan Beaumariage, Brian Fluegel, Ken West, Loren N. Pfeiffer, Angelo Mascarenhas

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4 Scopus citations


The Higgs amplitude mode is a collective excitation studied and observed in a broad class of matter, including superconductors, charge density waves, antiferromagnets, He3 p-wave superfluid, and ultracold atomic condensates. In all the observations reported thus far, the amplitude mode was excited by perturbing the condensate out of equilibrium. Studying an exciton-polariton condensate, here, we report the observation of this amplitude mode purely driven by intrinsic quantum fluctuations without such perturbations. By using an ultrahigh quality microcavity and a Raman spectrometer to maximally reject photoluminescence (PL) from the condensate, we observe weak but distinct PL at energies below the condensate emission. We identify this as the so-called ghost branches of the amplitude mode arising from quantum depletion of the condensate into this mode. These energies, as well as the overall structure of the PL spectra, are in good agreement with our theoretical analysis.

Original languageEnglish (US)
Article number205125
JournalPhysical Review B
Issue number20
StatePublished - May 14 2021
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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