We study the existence of smooth topological solitons and black strings as locally-stable saddles Euclidean gravitational action five dimensional Einstein-Maxwell theory. These objects live in Kaluza-Klein background four Minkowski with an $S^1$. compute off-shell canonical ensemble fixed boundary data corresponding to asymptotic radius $S^1$, electric magnetic charges that label strings. show ...

We show that the electroweak Z−string can be stabilized by the presence of bound states of a complex scalar field. We argue that fermions coupled to the scalar field of the string can also make the string stable and discuss the physical case where the string is coupled to quarks and leptons. This stabilization mechanism is expected to work for other embedded defects and also for unstable soluti...

We construct a non-topological string solution for supersymmetric gauge theory with $SU(2)\times U(1)$ symmetry which is spontaneously broken to $U(1)$ by developing the vacuum expectation value of two doublet Higgses. It extension electroweak while supersymmetry unbroken. discuss classical stability perturbations. show that are determined only parameters, and allowed region becomes essentially...

Abstract In order to improve the security of drilling progress and reduce reliability impact which caused by collision between drill string well wall, finite element analysis software ADINA is used establish a model simulate change stress after wellbore under different factors. The results show that existence fluid with higher viscosity, lower revolution speed autorotation larger annular space ...

Recent advances in vehicle connectivity have allowed formation of autonomous platoons for improved mobility and traffic throughput. In order to avoid a pile-up such platoons, it is important ensure platoon (string) stability, which the focus this work. As per conventional definition string power (2-norm) spacing error signals should not amplify downstream platoon. But practice, infinity-norm si...

We show that B-type Π-stable D-branes do not in general reduce to the (Gieseker-) stable holomorphic vector bundles used in mathematics to construct moduli spaces. We show that solutions of the almost Hermitian Yang–Mills equations for the non-linear deformations of Yang–Mills instantons that appear in the low-energy geometric limit of strings exist iff they are π-stable, a geometric version of...

Two-to-one parametric resonance in transverse vibration of an axially accelerating viscoelastic string with geometric nonlinearity is investigated. The transport speed is assumed to be a constant mean speed with small harmonic variations. The nonlinear partial differential equation that governs transverse vibration of the string is derived from Newton’s second law. The method of multiple scales...

The effect of perturbations of electroweak strings on quark zero modes is studied in 2+1 and 3+1 dimensions. As first discovered by Naculich, it is found that the bosonic perturbations that destabilize the string give a mass to the zero modes and also lift their degeneracy. The effect of the zero modes on the stability of the string is discussed qualitatively and we argue that the fermionic vac...