In type-II string theory compactifications on Calabi-Yau manifolds, topological string theory partition functions give a class of exact F-terms in the 4d effective action. We point out that in the background of constant self-dual field strength, these terms deform the central charges for D-branes wrapping Calabi-Yau manifold to include string loop corrections. We study the corresponding loop co...

We present a simplified and improved version of the string method, originally proposed by E et al. [Phys. Rev. B 66, 052301 (2002)] for identifying the minimum energy paths in barrier-crossing events. In this new version, the step of projecting the potential force to the direction normal to the string is eliminated and the full potential force is used in the evolution of the string. This not on...

In this paper, we propose a method to analyze the longitudinal dynamics of heterogeneous connected vehicle systems including human-driven vehicles and vehicles driven by connected cruise control. Human reaction time and digital sampling time are incorporated in the models. Conditions of plant stability and head-to-tail string stability are presented.

Classical stability behaviors of various static black brane backgrounds under small perturbations have been summarized briefly. They include cases of black strings in AdS5 space, charged black p-brane solutions in the type II supergravity, and the BTZ black string in four-dimensions. The relationship between dynamical stability and local thermodynamic stability the so-called Gubser-Mitra conjec...

We define the concept of Π-stability, a generalization of µ-stability of vector bundles, and argue that it characterizes N = 1 supersymmetric brane configurations and BPS states in very general string theory compactifications with N = 2 supersymmetry in four dimensions. February 2000

The minimal embedding of the Standard Model in type I string theory is described. The SU(3) color and SU(2) weak interactions arise from two different collections of branes. The correct prediction of the weak angle is obtained for a string scale of 6-8 TeV. Two Higgs doublets are necessary and proton stability is guaranteed. It predicts two massive vector bosons with masses at the TeV scale, as...

Vortex solutions in the two Higgs doublet electroweak model are constructed, and their stability to small perturbations is studied. The most general perturbation is decomposed into angular momentum modes, the least stable mode is identified, and the linearised energy change of the vortex under this perturbation is calculated numerically for various choices of parameters, thus determining whethe...

This paper presents experimental results, analytical findings, and simulation evaluations pertaining to the longitudinal dynamics and headway performance of strings of vehicles with and without adaptive cruise control (ACC) systems. It focuses on the amplification of speed disturbances along a string of vehicles, i.e., the stability of string behavior. The work describes measurement, analysis, ...

This paper is concerned with the study of bidirectionally coupled platoon systems. The case considered is when the vehicles are heterogeneous and the coupling can be asymmetric and nonlinear. For such systems, a sufficient condition for L∞ string stability is presented. The effectiveness of our approach is illustrated via a numerical example, where it is shown how our result can be recast as an...

We study the stability of extra dimensions in string gas cosmology at late times. Vacuum energy and, interestingly, baryons lead to decompactification after they become dynamically important. The string gas can stabilise the effect of baryons, but not that of vacuum energy. However, we find that the interplay of baryons and strings can lead to acceleration in the visible dimensions, without the...