A quantum phase transition detected through one dimensional ballistic conductance

TL;DR

This paper demonstrates that a quantum phase transition in ballistic quantum wires can be detected through conductance measurements, revealing universal scaling behavior linked to electron interactions and phase transition phenomena.

Contribution

It introduces a simple discretised model explaining anticrossing in quantum wires as a second order quantum phase transition within the Ising universality class.

Findings

Observation of anticrossing explained by the model

Universal scaling behavior across different samples

Identification of a quantum phase transition in ballistic conductance

Abstract

A quantum phase transition is an unequivocal signature of strongly correlated many-body physics. Signatures of such phenomena are yet to be observed in ballistic transport through quantum wires. Recent developments in quantum wires have made it possible to enhance the interaction between the electrons. Here we show that hitherto unexplained anticrossing between conduction energy sub-bands, observed in such experiments, can be explained through a simple yet effective discretised model which undergoes a second order quantum phase transition within the Ising universality class. Accordingly, we observe how the charge distribution, transverse to the direction of the wire will vary across the phase transition. We show that data coming from three different samples with differing electron densities and gate voltages show a remarkable universal scaling behavior, determined by the relevant critical exponent, which is only possible near a quantum phase transition.