Holographic s + p superconductors

We study the phase diagram of a holographic model realizing a U(2) global symmetry on the boundary and show that at low temperature a phase with both scalar s and vector p condensates exists. This is the s+p-wave phase where the global U(2) symmetry and also the spatial rotational symmetry are spontaneously broken. By studying the free energy we show that this phase is preferred when it exists. We also consider unbalanced configurations where a second chemical potential is turned on. They present a rich phase diagram characterized by the competition and coexistence of the s and p order parameters. © 2014 American Physical Society.Fil: Amado, Irene. Technion - Israel Institute of Technology; IsraelFil: Areán, Daniel. The Abdus Salam; Italia. Istituto Nazionale Di Fisica Nucleare, Sezione Di Trieste; . The Abdus Salam. International Centre for Theoretical Physics; ItaliaFil: Jimenez Alba, Amadeo. Universidad Autónoma de Madrid; EspañaFil: Melgar, Luis. Universidad Autónoma de Madrid; EspañaFil: Salazar, Ignacio. The Abdus Salam. International Centre for Theoretical Physics; Italia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentin