Andreas Schmitt

When the transition temperature in color superconductors is not like in BCS theory

We study color superconductivity with

Magnetic catalysis in nuclear matter

N_f=1,2,

From a complex scalar field to the two-fluid picture of superfluidity

and 3 massless flavors of quarks. We present a general formalism to derive and solve the gap equations for condensation in the even-parity channel. This formalism shows that the leading-order contribution to the gap equation is unique for all color superconductors studied here, and that differences arise solely at the subleading order. We discuss a simple method to compute subleading contributions from the integration over gluon momenta in the gap equation. Subleading contributions enter the prefactor of the color-superconducting gap parameter. In the case of color-flavor and color-spin locking we identify further corrections to this prefactor arising from the two-gap structure of the quasiparticle excitations. Computing the transition temperature,

Instabilities in relativistic two-component (super)fluids

T_c

Layers of deformed instantons in holographic baryonic matter

, where the color-superconducting condensate melts, we find that these contributions lead to deviations from the BCS behavior

Role reversal in first and second sound in a relativistic superfluid

T_c\simeq 0.57 \phi_0

New color-magnetic defects in dense quark matter

, where

Superfluid two-stream instability in a microscopic model

\phi_0

Chiral transition in dense, magnetized matter

is the magnitude of the zero-temperature gap at the Fermi surface.

Critical magnetic fields in a superconductor coupled to a superfluid

A strong magnetic field enhances the chiral condensate at low temperatures. This so-called magnetic catalysis thus seeks to increase the vacuum mass of nucleons. We employ two relativistic field-theoretical models for nuclear matter, the Walecka model and an extended linear sigma model, to discuss the resulting effect on the transition between vacuum and nuclear matter at zero temperature. In both models we find that the creation of nuclear matter in a sufficiently strong magnetic field becomes energetically more costly due to the heaviness of magnetized nucleons, even though it is also found that nuclear matter is more strongly bound in a magnetic field. Our results are potentially important for dense nuclear matter in compact stars, especially since previous studies in the astrophysical context have always ignored the contribution of the magnetized Dirac sea and thus the effect of magnetic catalysis.