A D2-brane in the Penrose limits of AdS(4)x CP(3)

We consider a D2-brane in the pp-wave backgrounds obtained from AdS$_4\times$CP$^3$ when electric and magnetic fields have been turned on. Upon fixing the light-cone gauge, light-cone Hamiltonian and BPS configurations are obtained. In particular we study BPS configurations with electric dipole on the two sphere giant and a giant graviton rotating in transverse directions. Moreover we show that the gauge field living on the D2-brane is replaced by a scalar field in the light-cone Hamiltonian. We also present a matrix model by regularizing (quantizing) 2-brane theory.Comment: 14 page

Holographic Equilibration under External Dynamical Electric Field

The holographic equilibration of a far-from-equilibrium strongly coupled gauge theory is investigated. The dynamics of a probe D7-brane in an AdS-Vaidya background is studied in the presence of an external time-dependent electric field. Defining the equilibration times $t_{eq}^c$ and $t_{eq}^j$, at which condensation and current relax to their final equilibrated values, receptively, the smallness of transition time $k_M$ or $k_E$ is enough to observe a universal behaviour for re-scaled equilibration times $k_M k_E (t_{eq}^c)^{-2}$ and $k_M k_E (t_{eq}^j)^{-2}$. Moreover, regardless of the values for $k_M$ and $k_E$, $t_{eq}^c/t_{eq}^j$ also behaves universally for large enough value of the ratio of the final electric field to final temperature. Then a simple discussion of the static case reveals that $t_{eq}^c \leq t_{eq}^j$. For an out-of-equilibrium process, our numerical results show that, apart from the cases for which $k_E$ is small, the static time ordering persists.Comment: 6 pages, 8 figure

Entanglement Entropy in a Non-Conformal Background

We use gauge-gravity duality to compute entanglement entropy in a non-conformal background with an energy scale $\Lambda$. At zero temperature, we observe that entanglement entropy decreases by raising $\Lambda$. However, at finite temperature, we realize that both $\frac{\Lambda}{T}$ and entanglement entropy rise together. Comparing entanglement entropy of the non-conformal theory, $S_{A(N)}$, and of its conformal theory at the $UV$ limit, $S_{A(C)}$, reveals that $S_{A(N)}$ can be larger or smaller than $S_{A(C)}$, depending on the value of $\frac{\Lambda}{T}$.Comment: 5 pages, 3 figures, published versio

A Classical String in Lifshitz-Vaidya Geometry

We study the time evolution of the expectation value of a rectangular Wilson loop in strongly anisotropic time-dependent plasma using gauge-gravity duality. The corresponding gravity theory is given by describing time evolution of a classical string in the Lifshitz-Vaidya background. We show that the expectation value of the Wilson loop oscillates about the value of the static potential with the same parameters after the energy injection is over. We discuss how the amplitude and frequency of the oscillation depend on the parameters of the theory. In particular, by raising the anisotropy parameter, we observe that the amplitude and frequency of the oscillation increase.Comment: 19 pages, 5 figure