Generalized Lee-Wick Formulation from Higher Derivative Field Theories

We study a higher derivative (HD) field theory with an arbitrary order of derivative for a real scalar field. The degree of freedom for the HD field can be converted to multiple fields with canonical kinetic terms up to the overall sign. The Lagrangian describing the dynamics of the multiple fields is known as the Lee-Wick (LW) form. The first step to obtain the LW form for a given HD Lagrangian is to find an auxiliary field (AF) Lagrangian which is equivalent to the original HD Lagrangian up to the quantum level. Till now, the AF Lagrangian has been studied only for N=2 and 3 cases, where $N$ is the number of poles of the two-point function of the HD scalar field. We construct the AF Lagrangian for arbitrary $N$. By the linear combinations of AF fields, we also obtain the corresponding LW form. We find the explicit mapping matrices among the HD fields, the AF fields, and the LW fields. As an exercise of our construction, we calculate the relations among parameters and mapping matrices for $N=2,3$, and 4 cases.Comment: 23 pages, version to appear in PRD, we improved the transformation from HD to LW in Subsection 3.1, added comments on gauge field related with AF Lagrangians in Conclusion, and added reference

Late Time Behaviors of an Inhomogeneous Rolling Tachyon

We study an inhomogeneous decay of an unstable D-brane in the context of Dirac-Born-Infeld~(DBI)-type effective action. We consider tachyon and electromagnetic fields with dependence of time and one spatial coordinate, and an exact solution is found under an exponentially decreasing tachyon potential, $e^{-|T|/\sqrt{2}}$, which is valid for the description of the late time behavior of an unstable D-brane. Though the obtained solution contains both time and spatial dependence, the corresponding momentum density vanishes over the entire spacetime region. The solution is governed by two parameters. One adjusts the distribution of energy density in the inhomogeneous direction, and the other interpolates between the homogeneous rolling tachyon and static configuration. As time evolves, the energy of the unstable D-brane is converted into the electric flux and tachyon matter.Comment: 17 pages, 1 figure, version to appear in PR

Janus ABJM Models with Mass Deformation

We construct a large class of ${\cal N} = 3$ Janus ABJM models with mass deformation, where the mass depends on a spatial (or lightcone) coordinate. We also show that the resulting Janus model can be identified with an effective action of M2-branes in the presence of a background self-dual 4-form field strength varying along one spatial (or lightcone) coordinate.Comment: 17 pages, references added, published versio

Massive field contributions to the QCD vacuum tunneling amplitude

For the one-loop contribution to the QCD vacuum tunneling amplitude by quarks of generic mass value, we make use of a calculational scheme exploiting a large mass expansion together with a small mass expansion. The large mass expansion for the effective action is given by a series involving higher-order Seeley-DeWitt coefficients, and we carry this expansion up to order $1/(m\rho)^8$, where $m$ denotes mass of the quark and $\rho$ the instanton size parameter. For the small mass expansion, we use the known exact expression for the particle propagation functions in an instanton background and evaluate explicitly the effective action to order $(m\rho)^2$. A smooth interpolation of the results from both expansions suggests that the quark contribution to the instanton tunneling amplitude have a relatively simple $m\rho$-dependent behavior.Comment: revtex, 4figures, 33page

BPS D-branes from an Unstable D-brane in a Curved Background

We find exact tachyon kink solutions of DBI type effective action describing an unstable D5-brane with worldvolume gauge field turned on in a curved background. The background of interest is the ten-dimensional lift of the Salam-Sezgin vacuum and, in the asymptotic limit, it approaches ${\rm R}^{1,4}\times {\rm T}^2\times {\rm S}^3$. The solutions are identified as composites of lower-dimensional D-branes and fundamental strings, and, in the BPS limit, they become a D4D2F1 composite wrapped on ${\rm R}^{1,2}\times {\rm T}^2$ where ${\rm T}^2$ is inside ${\rm S}^3$. In one class of solutions we find an infinite degeneracy with respect to a constant magnetic field along the direction of NS-NS field on ${\rm S}^3$.Comment: 16 pages, 2 figures, a footnote added, typos corrected and a reference adde

Holographic Entanglement Entropy of Anisotropic Minimal Surfaces in LLM Geometries

We calculate the holographic entanglement entropy (HEE) of the $\mathbb{Z}_k$ orbifold of Lin-Lunin-Maldacena (LLM) geometries which are dual to the vacua of the mass-deformed ABJM theory with Chern-Simons level $k$. By solving the partial differential equations analytically, we obtain the HEEs for all LLM solutions with arbitrary M2 charge and $k$ up to $\mu_0^2$-order where $\mu_0$ is the mass parameter. The renormalized entanglement entropies are all monotonically decreasing near the UV fixed point in accordance with the $F$-theorem. Except the multiplication factor and to all orders in $\mu_0$, they are independent of the overall scaling of Young diagrams which characterize LLM geometries. Therefore we can classify the HEEs of LLM geometries with $\mathbb{Z}_k$ orbifold in terms of the shape of Young diagrams modulo overall size. HEE of each family is a pure number independent of the 't Hooft coupling constant except the overall multiplication factor. We extend our analysis to obtain HEE analytically to $\mu_0^4$-order for the symmetric droplet case.Comment: 15 pages, 1 figur