Quantum behavior of a heavy impurity strongly coupled to a Bose gas

TL;DR

This paper explores how a heavy impurity interacts with a dilute Bose gas at zero temperature, revealing quantum blockade effects and universal bound states due to quantum correlations, which are not captured by classical models.

Contribution

It demonstrates the quantum blockade effect and universal bound states in impurity-Bose gas systems using quantum Monte Carlo and basis methods, highlighting the role of quantum correlations.

Findings

Quantum blockade effect induced by boson-boson interactions.

Universal few-body bound states linked to quantum correlations.

Logarithmic dependence of polaron energy on scattering length.

Abstract

We investigate the problem of an infinitely heavy impurity interacting with a dilute Bose gas at zero temperature. When the impurity-boson interactions are short ranged, we show that boson-boson interactions induce a quantum blockade effect, where a single boson can effectively block or screen the impurity potential. Since this behavior depends on the quantum granular nature of the Bose gas, it cannot be captured within a standard classical-field description. Using a combination of exact quantum Monte Carlo methods and a truncated basis approach, we show how the quantum correlations between bosons lead to universal few-body bound states and a logarithmically slow dependence of the polaron ground-state energy on the boson-boson scattering length. Moreover, we expose the link between the polaron energy and the spatial structure of the quantum correlations, spanning the infrared to ultraviolet physics.