arXiv subjects
Publications and source records attributed to Syoji Zeze.
We investigate open string fluctuations around multibrane solutions within the $KBc$ subspace of open string field theory. Specifically, we consider space-time independent fluctuations of leading order zero in the $1/G$ expansion. A constraint on fluctuations around a multibrane solution is explicitly derived from the equation of motion.
We introduce a novel representation of Virasoro algebra in open string field theory. Elements of the algebra are vector fields on the $K$-space, where $K$ is the string field that generates a world sheet strip in sliver frame. The generators introduce a global symmetry of open string field theory. We also derive a representation of Virasoro algebra for nontrivial open string background described by the formal pure gauge solution. Generators for 0, 1 and 2 D-branes are explicitly studied and different behaviors around $K=0$ are observed.
It is known that the Takahashi--Tanimoto identity-based solution in open string field theory derives a kinetic operator which is a sum of twisted Virasoro generators. Applying the infinite circumstance description of conformal field theory, we derive continuous Virasoro algebra associated with the kinetic operator. Mode expansions of Virasoro generators and the modified BRST charge are given.
A ghost D-brane has been proposed as an object that cancels the effects of a D-branes. We construct a classical solution with an arbitrary number of D-branes and ghost D-branes in the context of open string field theory. Cancellation of BRST cohomolgy between D-branes and ghost D-branes is shown.
We demonstrate that a Hermitian matrix model can be derived from level truncated open string field theory with Chan-Paton factors. The Hermitian matrix is coupled with a scalar and a $U(N)$ vector which are responsible for the D-brane at the tachyon vacuum. Effective potential for the scalar is evaluated both in finite and large $N$. Increase of potential height is observed in both examples. The large $N$ matrix integral is identified with a system of $N$ ZZ branes and a ghost FZZT brane.
Using Maccaferri's formula, we derive new wedge based solutions of open string field theory. The solutions are gauge equivalent to the Takahashi-Tanimoto scalar solutions. The classical action and the gauge invariant overlap are evaluated analytically. We find a perturbative vacuum solution whose gauge invariant observables vanish. We also identify a tachyon vacuum solution whose gauge invariant observables are identical to those of the Erler-Schnabl solution.
We argue validity of purely ghost kinetic operator in open string field theory from the perspective of the modern analytic method based on the $K B c$ subalgebra. A purely ghost kinetic operator is obtained as a result of gauge fixing string field theory around the identity based tachyon vacuum solution. It is shown that the obtained kinetic operator is not equivalent to the midpoint insertion of the conformal ghost which is extensively studied in literature. We also find that the equation of motion does not allow any nontrivial solutions.
The result and outcome of the \textit{cloud chamber project}, which aims to develop a cloud chamber useful for science education is reported in detail. A project includes both three high school students and a teacher as a part of Super Science High School (SSH) program in our school. We develop a dry-ice-free cloud chamber using salt and ice (or snow). Technical details of the chamber are described. We also argue how the project have affected student's cognition, motivation, academic skills and behavior. The research project has taken steps of professional researchers, i.e., in planning research, applying fund, writing a paper and giving a talk in conferences. From interviews with students, we have learnt that such style of scientific activity is very effective in promoting student's motivation for learning science.
We present a sensitive diffusion cloud chamber which does not require any radioactive sources. A major difference from a commonly used chamber is use of a heat sink as its bottom plate. A result of a performance test of the chamber is given.
We demonstrate that an Erler-Schnabl type solution in cubic string field theory can be naturally interpreted as a gauge invariant regularization of an identity based solution. We consider a solution which interpolates between an identity based solution and ordinary Erler-Schnabl one. Two gauge invariant quantities, the classical action and the closed string tadpole, are evaluated for finite value of the gauge parameter. It is explicitly checked that both of them are independent of the gauge parameter.
We evaluate the classical action and the effective tachyon potential of open string field theory within KBc subalgebra, which is extensively used in analytic solution for tachyon condensation recently found by Erler and Schnabl. It is found that the level expansion of the string field terminates at level 3. We find that the closed string vacuum is a saddle point of the classical action. We also evaluate the effective potential for tachyon field. The closed string vaccum becomes stable by integrationg out an auxiliary field. It is found that the effective potential is bounded below hence has no runaway direction. We also argue validity of simple identity based solution.
We propose a new interpretation of the BFSS large N matrix quantum mechanics analogous to a novel interpretation of the IKKT matrix model where infinitely large N matrices act as differential operators in a curved space. In this picture, the Schrödinger equation in the BFSS model is regarded as the Wheeler-DeWitt equation which determines the wave function of universe. An explicit solution of wave function is studied in a simple two-dimensional minisuperspace model.
We construct classical solutions of open string field theory which are not invariant under ordinary twist operation. From detailed analysis of the moduli space of the solutions, it turns out that our solutions become nontrivial at boundaries of the moduli space. The cohomology of the modified BRST operator and the CSFT potential evaluated by the level truncation method strongly support the fact that our nontrivial solutions correspond to the closed string vacuum. We show that the nontrivial solutions are equivalent to the twist even solution which was found by Takahashi and Tanimoto, and twist invariance of open string field theory remains after the shift of the classical backgrounds.
We investigate classical solutions of string field theory proposed by Takahashi and Tanimoto in the case of even order polynomial functions. The BRS charge and the Feynman propagator of open string field theory expanded around the solution are specified by Jenkins-Strebel quadratic differential, which describes geometry of the string worldsheet. We show that the solution becomes nontrivial when two second order poles of the quadratic differential coincide each other on the unit disk. In this case, an open string boundary shrinks to a point.
We study a gauge fixed action of open string field theory expanded around the universal solution which has been found as an analytic classical solution with one parameter a. For a>-1/2, we are able to reproduce open string scattering amplitudes in the theory fixed in the Siegel gauge. At a=-1/2, all scattering amplitudes vanish and there is no open string excitation in the gauge fixed theory. These results support the conjecture that the universal solution can be regarded as pure gauge or the tachyon vacuum solution.
We investigate gauge invariant operators corresponding to on-shell closed string states in open string field theory. Using both oscillator representation and conformal mapping techniques, we calculate a two closed string tachyon amplitude that connects two gauge invariant operators by an open string propagator.We find that this amplitude is in a complete agreement with the usual disc amplitude.