Quantum-Zeno Fermi polaron in the strong dissipation limit

Abstract

The interplay between measurement and quantum correlations in many-body systems can lead to novel types of collective phenomena which are not accessible in isolated systems. In this work, we merge the Zeno-paradigm of quantum measurement theory with the concept of polarons in condensed-matter physics. The resulting quantum-Zeno Fermi-polaron is a quasi-particle which emerges for lossy impurities interacting with a quantum-degenerate bath of fermions. For loss rates of the order of the impurity-fermion binding energy the quasi-particle is short lived. However, we show that in the strongly dissipative regime of large loss rates a long-lived polaron branch re-emerges. This quantum-Zeno Fermi-polaron originates from the nontrivial interplay between the Fermi-surface and the surface of the momentum region forbidden by the quantum Zeno projection. The situation we consider here is realized naturally for polaritonic impurities in charge-tuneable semiconductors and can be also implemented using dressed atomic states in ultracold gases.