Equivalence of magnetic field and particle dilution in the strange metal state of CeCoIn$_5$

TL;DR

This paper investigates how magnetic field and particle dilution similarly affect the strange metallic state of CeCoIn$_5$, revealing that its properties are governed by the degree of quantum entanglement between local and itinerant electrons.

Contribution

It demonstrates the equivalence of magnetic field and particle dilution in tuning the strange metal state of CeCoIn$_5$, linking metallic properties to electron entanglement.

Findings

Magnetic field and particle dilution produce similar effects on CeCoIn$_5$'s metallic state.

The metallic properties are governed by quantum entanglement between local and itinerant electrons.

The strange metal state reflects the degree of electronic state disentanglement.

Abstract

The Bardeen-Cooper-Schrieffer mechanism for superconductivity is a triumph of the theory of many-body systems. Implicit in its formulation is the existence of long-lived (quasi)particles, originating from the electronic building blocks of the materials, which interact to form Cooper pairs that move coherently in lock-step. The challenge of unconventional superconductors is that it is not only unclear what the nature of the interactions are, but whether the familiar quasi-particles that form a superconducting condensate even exist. In this work, we reveal, by the study of applied magnetic field in electronically diluted materials, that the metallic properties of the unconventional superconductor CeCoIn$_5$ are determined by the degree of quantum entanglement that (Kondo) hybridizes local and itinerant electrons. This work suggests that the properties of the strange metallic state are a reflection of the disentanglement of the many-body state into the underlying electronic building blocks of the system itself.