arXiv subjects

Yuji Ando

Publications and source records attributed to Yuji Ando.

6 recordsLinked to original sources

arXiv2026

Singular field redefinition between Witten's string field theory and Witten's theory deformed by Ellwood invariant

We construct a field redefinition between Witten's string field theory and its deformation by the Ellwood invariant. This field redefinition is singular and does not imply physical equivalence between them. However, it allows us to formally transfer classical solutions of Witten's theory to solutions of the deformed theory. Although the resulting solutions are also generically singular and require careful examination of their physical interpretation, we show that the tachyon vacuum solution can be consistently transferred from Witten's theory to the deformed theory.

hep-th↗

arXiv2024

A consistent light-cone-gauge superstring field theory

Extending a recent development in the bosonic string field theory, we construct a map from the Witten-type gauge-invariant superstring field theory based on an $A_{\infty}$ structure to a light-cone-gauge superstring field theory via two intermediate theories, which we call the Kaku-type and Kugo-Zwiebach-type superstring field theories. We find that a naive extension only gives us an inconsistent light-cone-gauge theory that suffers from the well-known problem caused by divergence due to collisions of local operators. However, we also find that this difficulty may be resolved by considering the stubbed theory and propose it as a consistent light-cone-gauge superstring field theory. The result possibly gives a proof of the unitarity of the Witten-type superstring field theory.

hep-th↗

arXiv2024

Fast-forward scaling theory for quantum dynamics on curved space-time

Scaling properties inherent in quantum dynamics have been studied for various systems in terms of acceleration, deceleration and time reversing. We show a scaling property of quantum dynamics on curved space-time where gravity plays an essential role. We derive system parameters which realize speed-controlled dynamics. Moreover, we consider spatial scaling and derive system parameters which realize spatially-scaled quantum dynamics.

quant-ph↗

arXiv2023

Closed string amplitudes around tachyon vacuum solution in Kaku theory

We incorporate closed string field into Kaku's open string field theory which is defined by using Kaku vertex, and we construct open-closed string field theory. To do this, we define new consistent open-closed vertex and open-open-closed vertex with the Kaku vertex. Because these vertices depend on Chan-Paton parameter such as the Kaku vertex, the open-closed string field theory action that we construct depends on the Chan-Paton parameter such as the Kaku's theory action. However, we can show that an infinitesimal change of $l$ corresponds to a field redefinition. Furthermore, we compute closed string amplitudes around tachyon vacuum solution in this theory. As a result, we confirm that these are conventional pure closed string amplitudes on surfaces without boundaries.

hep-th↗

arXiv2023

Energy from Ellwood invariant for solutions involving $X^0$ variables

For some classical solutions $\Psi_\mathrm{sol}$ in Witten's bosonic string field theory, it was proven that energy of the solution is proportional to the Ellwood invariant $\mathrm{Tr}(\mathcal{V}\Psi_\mathrm{sol})$ with $\mathcal{V}=c\bar{c}\partial X^0\bar{\partial}X^0$. We examine the relation for solutions involving $X^0$ variables. As a result, we obtain that the relation may not hold for such solutions. Namely, there is a possibility that the energy is not proportional to the Ellwood invariant.

hep-th↗

arXiv2023

The classical solutions with $k_-=0$ in Kaku theory

We consider Kaku theory as introduced in M. Kaku, Phys. Lett. B 200, 22 (1988) and investigate classical solutions. In particular, we obtain that the equation of motion with the restriction $k_-=0$ in the Kaku theory is equivalent to the equation of motion in Witten theory. Because of this property, some solutions including the tachyon vacuum solution in the Witten theory satisfy also the equation of motion in the Kaku theory. In addition, we confirm that the cohomology around the tachyon vacuum solution is trivial also in the Kaku theory.

hep-th↗