Superfluid and metamagnetic phase transitions in ω-deformed gauged supergravity

Abstract

We study non-supersymmetric truncations of $\omega$-deformed ${\cal N}=8$ gauged supergravity that retain a $U(1)$ gauge field and three scalars, of which two are neutral and one charged. We construct dyonic domain-wall and black hole solutions with AdS$_4$ boundary conditions when only one (neutral) scalar is non-vanishing, and examine their behavior as the magnetic field and temperature of the system are varied. In the infrared the domain-wall solutions approach either dyonic AdS$_2 \times \mathbb{R}^2$ or else Lifshitz-like, hyperscaling violating geometries. The scaling exponents of the latter are $z=3/2$ and $\theta = -2$, and are independent of the $\omega$-deformation. New $\omega$-dependent AdS$_4$ vacua are also identified. We find a rich structure for the magnetization of the system, including a line of metamagnetic first-order phase transitions when the magnetic field lies in a particular range. Such transitions arise generically in the $\omega$-deformed theories. Finally, we study the onset of a superfluid phase by allowing a fluctuation of the charged scalar field to condense, spontaneously breaking the abelian gauge symmetry. The mechanism by which the superconducting instability ceases to exist for strong magnetic fields is different depending on whether the field is positive or negative. Finally, such instabilities are expected to compete with spatially modulated phases.