Quantum Criticality and the Alpha/Delta Puzzle

TL;DR

This paper proposes a novel explanation for the alpha-delta transition in plutonium, drawing an analogy with superconductors in magnetic fields, involving spin-orbit interactions and soliton formations.

Contribution

It introduces a new theoretical framework linking spin-orbit coupling effects to phase transitions in plutonium, inspired by superconductor vortex behavior.

Findings

Low energy monopole-like solitons arise from spin-orbit interactions in low carrier density metals.

In alpha-plutonium, solitons form an ordered solid state.

In delta-plutonium, solitons form a pair condensate.

Abstract

In this paper we suggest a novel explanation for the alpha-delta transition in plutonium based on an analogy between the evolution of the actinide ground state as a function of spin orbit coupling and the behaviour of thin film superconductors in a magnetic field. The key point is that in metals with a low carrier density spin-orbit interactions give rise to low energy monopole-like solitons with quantized spin currents, which play much the same role as Abrikosov vortices in thin film superconductors. In alpha-plutonium these solitons form an ordered solid, while in impurity stabilized delta-plutonium they form a pair condensate.