World-volume effective theories of locally non-geometric branes

We study world-volume effective theories of five-branes in type II string theories. We determine the bosonic zero-modes of the NS5-brane, the Kaluza-Klein monopole, the exotic Q5-, R5-branes and a space-filling brane, by direct calculations within the formalism of double field theory (DFT). We show that these zero-modes are Nambu-Goldstone modes associated with the spontaneously broken gauge symmetries in DFT. They are organized into the bosonic part of the six-dimensional $$ \mathcal{N} $$ N = (1) vector and the $$ \mathcal{N} $$ N = (2, 0) tensor multiplets. Among other things, we examine the locally non-geometric R5-branes and space-filling branes that are characterized by the winding space. We also study effective theories of five-branes with string worldsheet instanton corrections.

Chaos from massive deformations of Yang-Mills matrix models

We focus on an SU(N ) Yang-Mills gauge theory in 0 + 1-dimensions with the same matrix content as the bosonic part of the BFSS matrix model, but with mass deformation terms breaking the global SO(9) symmetry of the latter to SO(5) × SO(3) × ℤ2. Introducing an ansatz configuration involving fuzzy four and two spheres with collective time dependence, we examine the chaotic dynamics in a family of effective Lagrangians obtained by tracing over the aforementioned ansatz configurations at the matrix levels $$ N=\frac{1}{6} $$ N = 1 6 (n + 1)(n + 2)(n + 3), for n = 1, 2, · · · , 7. Through numerical work, we determine the Lyapunov spectrum and analyze how the largest Lyapunov exponents(LLE) change as a function of the energy, and discuss how our results can be used to model the temperature dependence of the LLEs and put upper bounds on the temperature above which LLE values comply with the Maldacena-Shenker-Stanford (MSS) bound 2πT , and below which it will eventually be violated.

On the structure of the emergent 3D expanding space in the Lorentzian type IIB matrix model

The emergence of (3+1)D expanding space-time in the Lorentzian type IIB matrix model is an intriguing phenomenon that has been observed in Monte Carlo studies of this model. In particular, this may be taken as support for the conjecture that the model is a nonperturbative formulation of superstring theory in (9+1) dimensions. In this paper we investigate the space-time structure of the matrices generated by simulating this model and its simplified versions, and find that the expanding part of the space is described essentially by the Pauli matrices. We argue that this is due to an approximation used in the simulation to avoid the sign problem, which actually amounts to replacing ${e}^{iS_{\rm b}}$ by ${e}^{\beta S_{\rm b}}$ ($\beta>0$) in the partition function, where $S_{\rm b}$ is the bosonic part of the action. We also discuss the possibility of obtaining a regular space-time with the (3+1)D expanding behavior in the original model with the correct ${e}^{iS_{\rm b}}$ factor.

Fermion fields in the (non)symmetric Kaluza–Klein theory

The paper is devoted to the unification of fermions within nonsymmetric Kaluza–Klein theories. We obtain a Lagrangian for fermions in non-Abelian Kaluza–Klein theory and non-Abelian Kaluza–Klein theory with spontaneous symmetry breaking and Higgs’ mechanism. A Lagrangian for fermions for geometrized bosonic part of GSW (Glashow–Salam–Weinberg) model in our approach has been derived. Yukawa-type terms and mass terms coming from higher dimensions have been obtained. In the paper, 1/2-spin fields and 3/2-spin fields are considered.

COVARIANT FORMULATION OF M-THEORY

We propose the bosonic part of an action that defines M-theory. It possesses manifest SO(1, 10) symmetry and constructed based on the Lorentzian 3-algebra associated with U(N) Lie algebra. From our action, we derive the bosonic sector of BFSS matrix theory and IIB matrix model in the naive large N limit by taking appropriate vacua. We also discuss an interaction with fermions.

REDUCED MODEL FOR SUPERSTRINGS ON AdSn × Sn

We review the Pohlmeyer reduction of the superstring sigma model on AdSn × Sn leading to a gauged WZW model with an integrable potential. In particular, we consider the case of GS superstrings on AdS3 × S3 supported by RR flux. The bosonic part of the reduced Lagrangian is given by the sum of the complex sine-Gordon Lagrangian and its sinh-Gordon counterpart. We determine the corresponding fermionic part and discuss possible 2d supersymmetry of the reduced action.

TOWARDS SO(2, 10)-INVARIANT M-THEORY: MULTI-LAGRANGIAN FIELDS

The SO (2, 10) covariant extension of M-theory superalgebra is considered, with the aim to construct a correspondingly generalized M-theory, or 11-D supergravity. For the orbit corresponding to the 11-D supergravity multiplet, the simplest unitary representations of the bosonic part of this algebra, with sixth-rank tensor excluded, are constructed on a language of field theory in 66-D space–time. The main peculiarities are the presence of more than one equation of motion and the corresponding Lagrangians for a given field and that the gauge and SUSY invariances of the theory mean that the sum of variations of these Lagrangians (with different variations of the same field) is equal to zero.