# Neutron star phase transition as the origin for the fast radio bursts and soft gamma-ray repeaters of SGR J1935+2154

**Authors:** Jun-Yi Shen, Yuan-Chuan Zou, Shu-Hua Yang, Xiao-Ping Zheng, Kai Wang  
**arXiv:** [2304.10871](https://arxiv.org/abs/2304.10871)  
**Date:** 2023-04-21  
**Summary page:** https://www.summarizepaper.com/en/paper/2304.10871v1/

## Key points

- Magnetars have strong magnetic fields and are of interest in astrophysics due to their X-ray flares and fast radio bursts (FRBs).
- SGR J1935+2154 is a soft gamma-ray repeater that emits both X-ray flares and repeating FRBs.
- A phase transition of a neutron star (NS) could be responsible for powering these events.
- The authors use the MIT bag model and mean field approximation to solve the Tolman-Oppenheimer-Volkoff equations and obtain the structure of a stable and metastable NS with a mass of 1.62M.
- Hadrons gradually transfer to quarks as they reach critical pressure, releasing gravitational potential energy in the process.
- If a large k is chosen, enough energy can be produced to power both SGRs and FRBs, consistent with observations.
- Phase transitions in NSs could be a plausible mechanism for powering not only SGRs but also cosmological repeating FRBs where their associated SGRs may be too weak to observe directly.
- This study provides new insights into understanding magnetars' behavior through investigating possible mechanisms behind their observed phenomena.

## Summary

In recent years, magnetars have become a topic of interest in the field of astrophysics due to their strong magnetic fields and the occurrence of X-ray flares and fast radio bursts (FRBs). In particular, the soft gamma-ray repeater SGR J1935+2154 has been observed to emit both X-ray flares and repeating FRBs. To investigate this phenomenon, the authors propose that a phase transition of a neutron star (NS) could be responsible for powering these events. To test this hypothesis, they use the MIT bag model and mean field approximation to solve the Tolman-Oppenheimer-Volkoff equations and obtain the structure of a stable and metastable NS with a mass of 1.62M. With spin-down effects taken into account, they find that hadrons gradually transfer to quarks as they reach critical pressure, releasing gravitational potential energy in the process. The authors compare their theoretical calculations with observations of SGR J1935+2154 and find that if a large k is chosen – which represents the strength of coupling between hadrons and quarks – then enough energy can be produced to power both SGRs and FRBs. The released energy, time interval between two successive phase transitions, and glitch magnitude are all consistent with observations. Based on these findings, the authors suggest that phase transitions in NSs could be a plausible mechanism for powering not only SGRs but also cosmological repeating FRBs where their associated SGRs may be too weak to observe directly. Overall, this study provides new insights into understanding magnetars' behavior through investigating possible mechanisms behind their observed phenomena. Further research in this area may help shed light on other mysterious astrophysical phenomena.