# Multiple universalities in order-disorder magnetic phase transitions

## TL;DR

This paper predicts multiple universal critical behaviors in quantum antiferromagnets under combined pressure and magnetic field, identifying new critical exponents and logarithmic corrections to scaling.

## Contribution

It introduces a relativistic quantum field theory framework predicting three distinct universalities and new critical exponents in order-disorder magnetic phase transitions.

## Key findings

- Prediction of three universal critical exponents including two new ones (1 and 1/2).
- Identification of logarithmic corrections to power-law scaling.
- Recovery of the known exponent 3/2 in the new theoretical context.

## Abstract

Phase transitions in isotropic quantum antiferromagnets are associated with the condensation of bosonic triplet excitations. In three dimensional quantum antiferromagnets, such as TlCuCl$_3$, condensation can be either pressure or magnetic field induced. The corresponding magnetic order obeys universal scaling with thermal critical exponent $\phi$. Employing a relativistic quantum field theory, the present work predicts the emergence of multiple (three) universalities under combined pressure and field tuning. Changes of universality are signalled by changes of the critical exponent $\phi$. Explicitly, we predict the existence of two new exponents $\phi=1$ and $1/2$ as well as recovering the known exponent $\phi=3/2$. We also predict logarithmic corrections to the power law scaling.