119262542
Coexistence and competition of ferromagnetism and p-wave superconductivity in holographic model
By combining a holographic $p$-wave superconductor model and a holographic ferromagnetism model, we study the coexistence and competition of ferromagnetism and $p$-wave superconductivity. It is found that the results depend on the self-interaction of magnetic moment of the complex vector field and which phase appears first. In the case where the ferromagnetic phase appears first, if the interaction is attractive, the system shows the ferromagnetism and superconductivity can coexist at low temperatures. If the interaction is repulsive, the system will only be in a pure ferromagnetic state. In the case where the superconducting phase appears first, the attractive interaction will lead to a magnetic $p$-wave superconducting phase at low temperatures. If the interaction is repulsive, the system will be in a pure $p$-wave superconducting phase or a ferromagnetic phase when the temperature is lowered.
119108999
Holographic model for the paramagnetism/antiferromagnetism phase transition
In this paper we build a holographic model of paramagnetism/antiferromagnetism phase transition, which is realized by introducing two real antisymmetric tensor fields coupling to the background gauge field strength and interacting with each other in a dyonic black brane background. In the case without external magnetic field and in low temperatures, the magnetic moments condense spontaneously in antiparallel manner with the same magnitude and the time reversal symmetry is also broken spontaneously (if boundary spatial dimension is more than 2, spatial rotational symmetry is broken spontaneously as well), which leads to an antiferromagnetic phase. In the case with weak external magnetic field, the magnetic susceptibility density has a peak at the critical temperature and satisfies the Curie-Weiss law in the paramagnetic phase of antiferromagnetism. In the strong external magnetic field case, there is a critical magnetic field $B_c$ in antiferromagnetic phase: when magnetic field reaches $B_c$, the system will return into the paramagnetic phase by a second order phase transition.
119289134
Large-scale structure in superfluid Chaplygin gas cosmology
We investigate the growth of the large-scale structure in the superfluid Chaplygin gas (SCG) model. Both linear and nonlinear growth, such as sigma(8) and the skewness S-3, are discussed. We find the growth factor of SCG reduces to the Einstein-de Sitter case at early times while it differs from the cosmological constant model (ACDM) case in the large a limit. We also find there will be more stricture growth on large scales in the SCG scenario than in ACDM and the variations of sigma 8 and S-3 between SCG and ACDM cannot be discriminated.
37596388
Is Gravity Entropic Force?
If we assume that the source of thermodynamic system, ρ and p, are also the source of gravity, then either thermal quantities, such as entropy, temperature, and chemical potential, can induce gravitational effects, or gravity can induce thermal effects. We find that gravity can be seen as entropic force only for systems with constant temperature and zero chemical potential. The case for Newtonian approximation is discussed.
120520435
Bound on the Equation of State of Dark Energy from the Generalized Second Law of Thermodynamics
Assuming that the equation of state of dark energy is a constant, we obtain the allowed interval of the equation of state of dark energy: wD≥−1, bounded from the generalized second law of thermodynamics, in a universe enveloped by the apparent horizon and containing a Schwarzschild black hole.