Speaker: Dr. Geraint Evans (AS)
Talk title: 3D Baryon crystal from the chiral anomaly
Time: 2024/09/16 (Mon.) 12:30 
Place: R517, New Physics Building

Abstract:
The phase structure of QCD at finite baryon chemical potential and large magnetic field is not only interesting from a purely theoretical perspective, but also may be important in understanding the matter present in neutron stars cores and produced in heavy-ion collisions. Including the effects of the chiral anomaly within Chiral Perturbation Theory at finite baryon chemical potential, it has been shown that neutral pions form an inhomogeneous phase dubbed the "Chiral Soliton Lattice" (CSL) above a certain critical magnetic field. Above a second, even higher critical field, the CSL becomes unstable to fluctuations of charged pions, implying they condense. 

I will point out the similarity of this second critical field to the upper critical magnetic field in conventional type-II superconductors, suggesting that an inhomogeneous phase of superconducting charged pion exists beyond this point. Applying similar methods originally used by Abrikosov, I will present results where we've constructed such a phase and show the region where it is preferred in the baryon chemical potential-magnetic field phase diagram at zero temperature. This new phase has a non-zero baryon number density which is periodic in all three spatial dimensions.

G. W. Evans and A. Schmitt, JHEP 09, 192 (2022), arXiv:2206.01227 [hep-th] 
G. W. Evans and A. Schmitt, JHEP 2024, 041 (2024), arXiv:2311.03880 [hep-th]