Sarma phase in relativistic and non-relativistic systems

We investigate the stability of the Sarma phase in two-component fermion systems in three spatial dimensions. For this purpose we compare strongly-correlated systems with either relativistic or non-relativistic dispersion relation: relativistic quarks and mesons at finite isospin density and spin-imbalanced ultracold Fermi gases. Using a Functional Renormalization Group approach, we resolve fluctuation effects onto the corresponding phase diagrams beyond the mean-field approximation. We find that fluctuations induce a second order phase transition at zero temperature, and thus a Sarma phase, in the relativistic setup for large isospin chemical potential. This motivates the investigation of the cold atoms setup with comparable mean-field phase structure, where the Sarma phase could then be realized in experiment. However, for the non-relativistic system we find the stability region of the Sarma phase to be smaller than the one predicted from mean-field theory. It is limited to the BEC side of the phase diagram, and the unitary Fermi gas does not support a Sarma phase at zero temperature. Finally, we propose an ultracold quantum gas with four fermion species that has a good chance to realize a zero-temperature Sarma phase.Comment: version published in Phys.Lett.B; 10 pages, 5 figure

Intranasal immunization with an Apolipoprotein B-100 fusion protein induces antigen-specific regulatory T cells and reduces Atherosclerosis

OBJECTIVE: Atherosclerosis is an inflammatory disease. Autoimmune responses to low-density lipoproteins (LDL) contribute to its progression, whereas immunization with LDL may induce atheroprotective or proatherogenic responses. The objective of this study was to develop an atheroprotective vaccine by targeting a peptide of the LDL protein constituent apolipoprotein B-100 (apoB-100) to the nasal mucosa to induce a protective mucosal immune response. METHODS AND RESULTS: A peptide comprising amino acids 3136 to 3155 of apoB-100 (p210) was fused to the B subunit of cholera toxin (CTB), which binds to a ganglioside on mucosal epithelia. The effect of nasal administration of the p210-CTB fusion protein on atherogenesis was compared with that of an ovalbumin peptide fused to CTB and with untreated controls. Immunization with p210-CTB for 12 weeks caused a 35% reduction in aortic lesion size in Apoe(-/-) mice. This effect was accompanied by induction regulatory T cells that markedly suppressed effector T cells rechallenged with apoB-100 and increased numbers of interleukin (IL)-10(+) CD4(+) T cells. Furthermore, a peptide-specific antibody response was observed. Atheroprotection was also documented in apoe(-/-) mice lacking functional transforming growth factor-beta receptors on T cells. CONCLUSIONS: Nasal administration of an apoB-100 peptide fused to CTB attenuates atherosclerosis and induces regulatory Tr1 cells that inhibit T effector responses to apoB-100