arXiv subjects
Publications and source records attributed to Koichi Nagasaki.
String geometry theory is one of the candidates of the non-perturbative formulation of string theory. In this paper, in the bosonic closed sector of string geometry theory, we completely identify the perturbative vacua, which include general string backgrounds in bosonic closed string theory. From fluctuations around these configurations, we derive the path-integrals of perturbative strings on the string backgrounds up to any order.
String geometry theory is one of the candidates of the non-perturbative formulation of superstring theory. In this paper, in string geometry theory, we identify perturbative heterotic vacua, which include general heterotic backgrounds. From fluctuations around these vacua, we derive the path-integrals of heterotic perturbative superstrings on the backgrounds up to any order.
In this work we consider a spacial kind of spacetime called AdS accelerating black holes. This is a kind of black holes which contain a stringlike singularity along polar axises attached to the black hole and it accelerates the black hole. In these kind of spacetimes the growth of Einstein-Hilbert action is independent of the acceleration as found in the previous works. By using a string as a probe, we found the effect of the acceleration is captured by the string prove in our previous work. Here in this work we consider the case of rotating black holes. By the prove string we clearly describe the effect of the acceleration and its relation to the rotation of the black holes.
In this work we consider a spacial kind of spacetime called AdS accelerating black holes. This is a kind of black holes which contain a stringlike singularity along polar axises attached to the black hole and it accelerates the black hole. By using a string as a probe we study the properties of complexity growth of black holes following the CA duality. Our result is the growth of complexity is independent of acceleration but the string probe detects the effects of acceleration.
We find the probe D5-brane solution on the black home spacetime which is asymptomatically AdS_5 x S^5. These black holes have spherical, hyperbolic and toroidal structures. Depending on the gauge flux on the D5-brane, the D5-brane behaves differently. This By adding the fundamental string, the potential energy of the interface solution and the Wilson loop is given in the case of non zero gauge flux.
Our interest is to find the difference of the behavior between black holes with three different topologies. These black holes have spherical, hyperbolic and toroidal structures. We study in this paper the behavior of a probe D5-branes in this nontrivial black hole spacetime. We would like to find the solution what describe the embedding of probe D5-brane. This system realizes an "interface" solution, a kind of non-local operators, on the boundary gauge theories. These operators are important to deepen understanding of AdS/CFT correspondence.
We consider the growth of the action for black hole spacetime with a fundamental string. Our interest is to find the difference of the behavior between black holes with three different topologies in the scenario of complexity-action conjecture. These black holes have positive, negative and zero curvatures. We would like to calculate the action growth of these systems with a probe fundamental string according to the complexity-action conjecture. We find that for the case where the black holes have the toroidal horizon structure this probe string behaves very differently from the other two cases.
We consider a D5-brane solution in AdS black hole spacetime. This is a defect solution moving in subspace of AdS5 x S5. This non-local object is realized by the probe D5-brane moving in black hole spacetime. We found this probe brane does not penetrate the black hole horizon. We also found the solution does not depend on the motion on S5 subspace.
We consider a defect solution in the AdS5 x S5 spacetime. This is the generalization of the previous work [arXiv:1109.1927] to the other spacetime. This also gives the generalization of Complexity and Action relation [arXiv:1705.08424] including the flux. The equation of motion for an interface is given and its solution is shown by the numerical calculation. We also consider the Nambu-Goto action of the string affected by this interface. This corresponds the quark-interface potential in the black hole spacetime.
A defect solution in the AdS5 x S5 black hole spacetime is given. This is a generalization of the previous work to another spacetime. The equation of motion for a sort of non-local operator, "an interface," is given and its numerical solution is shown. This result gives a new example of holographic relation of complexity and will be a clue for solving problems about black hole complexity.
We study the effect of a probe string to black hole complexity according to the CA (Complexity equals Action) conjecture. Our system contains a particle moving on the boundary of black hole spacetime. In the dual description this corresponds to the insertion of a fundamental string on the bulk spacetime. The total action consists of the Einstein-Hilbert term and the Nambu-Goto term. The effect of this string is expressed by the Nambu-Goto term. Focusing on the Nambu-Goto term, we analyse the time development of this system. Our results show some interesting properties of complexity. This gives a useful hint for defining complexity in quantum field theories.
We consider charged rotating BTZ black holes in noncommutative space by use of Chern-Simons theory formulation of $2+1$ dimensional gravity. The noncommutativity between the radial and the angular variables is introduced through the Seiberg-Witten map for gauge fields, and the deformed geometry to the first order in the noncommutative parameter is derived. It is found that the deformation also induces nontrivial torsion, and the Einstein-Cartan theory appears to be a suitable framework to investigate the equations of motion. Though the deformation is indeed nontrivial, the deformed and the original Einstein equations are found to be related by a rather simple coordinate transformation.
We consider computational complexity of AdS_5 black holes. Our system contains a particle moving on the boundary of AdS. This corresponds to the insertion of a fundamental string in AdS_5 bulk spacetime. Our results give a constraint for complexity. This gives us a hint for defining complexity in quantum field theories.
We consider the partition function of super Yang-Mills theories defined on $T^2 \times Σ_g$. This path integral can be computed by the localization. The one-loop determinant is evaluated by the elliptic genus. This elliptic genus gives trivial result in our calculation. As a result, we obtain a theory defined on the Riemann surface.
By compactifying gauge theories on a lower dimensional manifold, we often find many interesting relationships between a geometry and a supersymmetric quantum field theory. In this paper we consider conformal field theories obtained from twisted compactification on a Riemann surface with a boundary. Various kinds of supersymmetric boundary conditions are exchanged under S-duality. To consider these transformations one need to take into account boundary degrees of freedom. So we study how the degrees of freedom can be added at the boundary of the Riemann surface. In this paper I show that this introduction of the boundary fields can be done preserving supersymmetry by means of 2-dimensional superfields.
We consider a 2-dimensional conformal field theory (CFT) obtained from twisted compactification of the 4-dimensional N=4 super Yang-Mills theory on a Riemann surface with boundary. We find the boundary conditions to preserve some of the supersymmetry. In particular an N=(2,2) superconformal field theory is obtained from supersymmetry breaking due to the boundary from N=(4,4). In this case we calculate the central charge of the CFT and show its dependence on the topology of the Riemann surface.
We consider a brane configuration consisting of a D5-brane, D1-branes and D3-branes. According to the AdS/CFT correspondence this system realizes a 't Hooft operator embedded in the interface in the gauge theory side. In the gravity side the near-horizon geometry is AdS_5 x S^5. The D5-brane is treated as a probe in the AdS_5 x S^5 and the D1-branes become the gauge flux on the D5-brane. We examine the condition for preserving appropriate amount of supersymmetry and derive a set of differential equations which is the sufficient and necessary condition. This supersymmetric configuration shows bubbling behavior. We try to derive the relation between the probe D5-brane and the Young diagram which labels the corresponding 't Hooft operator. We propose the dictionary of the correspondence between the Young diagram and the probe D5-brane configuration.
We consider the expectation values of chiral primary operators in the presence of the interface in the 4 dimensional N=4 super Yang-Mills theory. This interface is derived from D3-D5 system in type IIB string theory. These expectation values are computed classically in the gauge theory side. On the other hand, this interface is a holographic dual to type IIB string theory on AdS_5 x S^5 spacetime with a probe D5-brane. The expectation values are computed by GKPW prescription in the gravity side. We find non-trivial agreement of these two results: the gauge theory side and the gravity side.