# Trace Anomaly as Signature of Conformality in Neutron Stars.

@article{Fujimoto2022TraceAA, title={Trace Anomaly as Signature of Conformality in Neutron Stars.}, author={Yuki Fujimoto and Kenji Fukushima and Larry Mclerran and Michał Praszałowicz}, journal={Physical review letters}, year={2022}, volume={129 25}, pages={ 252702 } }

We discuss an interpretation that a peak in the sound velocity in neutron star matter, as suggested by the observational data, signifies strongly coupled conformal matter. The normalized trace anomaly is a dimensionless measure of conformality leading to the derivative and the nonderivative contributions to the sound velocity. We find that the peak in the sound velocity is attributed to the derivative contribution from the trace anomaly that steeply approaches the conformal limit. Smooth…

## 5 Citations

### Pseudo-Conformal Sound Speed in the Core of Compact Stars

- PhysicsSymmetry
- 2022

By implementing the putative “hadron-quark continuity" conjectured in QCD in terms of skyrmion-half-skyrmion topological change in an effective field theory for dense matter, we argue that…

### Equation of state and speed of sound of isospin-asymmetric QCD on the lattice

- Physics
- 2022

: We determine the QCD equation of state at nonzero temperature in the presence of an isospin asymmetry between the light quark chemical potentials on the lattice. Our simulations employ N f = 2 + 1…

### Isothermal and isentropic speed of sound in (2+1)-flavor QCD at non-zero baryon chemical potential

- Physics
- 2022

Recently interest in calculations of the speed of sound in QCD under conditions like constant temperature 𝑐 2 𝑇 or constant entropy per net baryon number 𝑐 2 𝑠 arose in the discussion of…

### Causality violation and the speed of sound of hot and dense quark matter in the Nambu--Jona-Lasinio model

- Physics
- 2023

. The Nambu–Jona-Lasinio model is widely used to study strong-interaction phenomena in the vacuum and quark matter. Since the model is nonrenormalizable, one needs to work within a speciﬁc…

### The isentropic equation of state of (2+1)-flavor QCD: An update based on high precision Taylor expansion and Pade-resummed expansion at finite chemical potentials

- PhysicsProceedings of The 39th International Symposium on Lattice Field Theory — PoS(LATTICE2022)
- 2023

The HotQCD Collaboration performed Taylor expansion calculations in 2017 for the pressure, energy density

### Chiral restoration of nucleons in neutron star matter: studies based on a parity doublet model

- Physics
- 2023

: We review the chiral variant and invariant components of nucleon masses and its consequence on the chiral restoration in extreme conditions, neutron star matter in particular. We consider a model…

## References

SHOWING 1-10 OF 38 REFERENCES

### Constraining the Speed of Sound inside Neutron Stars with Chiral Effective Field Theory Interactions and Observations

- PhysicsThe Astrophysical Journal
- 2018

The dense matter equation of state (EOS) determines neutron star (NS) structure but can be calculated reliably only up to one to two times the nuclear saturation density, using accurate many-body…

### Quark-matter cores in neutron stars

- Physics
- 2019

We combine results from astrophysical observations and theoretical ab-initio calculations to investigate the presence of quark matter (QM) inside neutron stars (NSs). We find a clear qualitative…

### Shapiro delay measurement of a two solar mass neutron star

- Physics
- 2010

Neutron stars are composed of the densest form of matter known to exist in our universe, and thus provide a unique laboratory for exploring the properties of cold matter at supranuclear density.…

### QCD equations of state and speed of sound in neutron stars

- PhysicsAAPPS Bulletin
- 2020

Neutron stars are cosmic laboratories to study dense matter in quantum chromodynamics (QCD). The observable mass-radius relations of neutron stars are determined by QCD equations of state and can…

### New Neutron Star Equation of State with Quark–Hadron Crossover

- PhysicsThe Astrophysical Journal
- 2019

We present a much improved equation of state for neutron star matter, QHC19, with a smooth crossover from the hadronic regime at lower densities to the quark regime at higher densities. We now use…

### QCD at a Finite isospin density: From the pion to quark-antiquark condensation

- Physics
- 2000

QCD at a finite isospin chemical potential μI is studied. This theory has no fermion-sign problem and can be simulated on a lattice by using present-day techniques. We solve this theory analytically…

### Using Gravitational-wave Observations and Quasi-universal Relations to Constrain the Maximum Mass of Neutron Stars

- Physics
- 2017

Combining the GW observations of merging systems of binary neutron stars and quasi-universal relations, we set constraints on the maximum mass that can be attained by nonrotating stellar models of…

### Chiral Effective Field Theory and the High-Density Nuclear Equation of State

- Physics
- 2021

Recent advances in neutron star observations have the potential to constrain the properties of strongly interacting matter at extreme densities and temperatures that are otherwise difficult to access…