Bose polarons near quantum criticality
Abstract
The emergence of quasiparticles in interacting matter represents one of the cornerstones of modern physics. However, in the vicinity of a quantum critical point, the existence of quasiparticles comes under question. Here, we created Bose polarons near quantum criticality by immersing atomic impurities in a Bose-Einstein condensate (BEC) with near-resonant interactions. Using radiofrequency spectroscopy, we probed the energy, spectral width, and short-range correlations of the impurities as a function of temperature. Far below the superfluid critical temperature, the impurities formed well-defined quasiparticles. Their inverse lifetime, given by their spectral width, increased linearly with temperature at the so-called Planckian scale, consistent with quantum critical behavior. Close to the BEC critical temperature, the spectral width exceeded the impurity’s binding energy, signaling a breakdown of the quasiparticle picture.
- Publication:
-
Science
- Pub Date:
- April 2020
- DOI:
- 10.1126/science.aax5850
- arXiv:
- arXiv:1904.02685
- Bibcode:
- 2020Sci...368..190Y
- Keywords:
-
- PHYSICS;
- Condensed Matter - Quantum Gases;
- Physics - Atomic Physics;
- Quantum Physics
- E-Print:
- 17 pages, 14 figures