Dynamical meson melting in holography

Abstract

We discuss mesons in thermalizing gluon backgrounds in the N = 2 supersymmetric QCD using the gravity dual. We numerically compute the dynamics of a probe D7-brane in the Vaidya-AdS geometry that corresponds to a D3-brane background thermalizing from zero to finite temperatures by energy injection. In static backgrounds, it has been known that there are two kinds of brane embeddings where the brane intersects the black hole or not. They correspond to the phases with melted or stable mesons. In our dynamical setup, we obtain three cases depending on final temperatures and injection time scales. The brane stays outside of the black hole horizon when the final temperature is low, while it intersects the horizon and settles down to the static equilibrium state when the final temperature is high. Between these two cases, we find the overeager case where the brane dynamically intersects the horizon although the final temperature is not high enough for a static brane to intersect the horizon. The interpretation of this phenomenon in the dual field theory is meson melting due to non-thermal effects caused by rapid energy injection. In addition, we comment on the late time evolution of the brane and a possibility of its reconnection.

Meson excitation at finite chemical potential

“…whereV (v) = dV (v) dv . The same results are obtained for u = v + L. We refer the interested reader to [7] for more details.…”

“…When the energy injection ceases, the pair relaxes toward a final excited state with specify frequency and amplitude of oscillation. In other words, these oscillations can be interpreted as if the energy injection puts the meson in the excited state [7]. We are now interested in investigating the effect of three parameters final chemical potential µ f , final temperature T f and the distance between the quark and antiquark l on the characteristic of oscillation, i.e.…”

“…The subscript "R" in (22) refers to the regularized version of W(t). To calculate the string on-shell action, similar to [7], we choose the null coordinates (u, v) to parametrize the two-dimensional world-sheet of the string and therefore all the coordinates on the world-sheet depend on u and v. Then we choose the following ansatz:…”

Meson turbulence at quark deconfinement from AdS/CFT

“…Indeed, if we change the mass of the black hole in the bulk by the method in Ref. [53], namely temperature quench, we can confirm occurrence of the meson turbulence. It is expected that the turbulence can universally occur for wider systems of fluctuations of the probe branes.…”

Confining D-instanton background in an external electric field

“…In this regard, it would be interesting to study the evolution of a confining theory like the one in the present paper under electric field quenches, as an important class of quenches. We would follow this path using appropriate numerical techniques [33][34][35] in our future work.…”