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arXiv 0809.2013hep-thastro-phgr-qchep-ph
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Dirac Born Infeld(DBI)宇宙弦

Dirac Born Infeld (DBI) Cosmic Strings

Eugeny Babichev, Philippe Brax, Chiara Caprini, Jerome Martin, Daniele Steer

摘要:

受膜物理的启发,我们考虑了阿贝尔-希格斯模型的非线性DBI扩展,并研究了相应的宇宙弦构型。该模型被定义为一个潜在的长期,假设是墨西哥帽的形式,和DBI行动的动力学条款。我们表明,这是一个连续变形的阿贝尔-希格斯模型,与一个单一的变形参数依赖于一个无量纲的组合的标量耦合常数,真空的期望值的标量场在无穷远,和膜张力。通过数值计算,我们研究了相应的DBI宇宙弦的轮廓,并证明了它们有一个比阿贝尔-希格斯弦窄的核。我们还表明,相应的行动是小于在标准的情况下,这表明它们的形成可能有利于膜模型。此外,我们还证明了DBI宇宙弦解在参数空间中处处是非病态的。最后,在DBI模型约化为Bogomolnyi-Prasad-Sommerfield(BPS)阿贝尔-希格斯模型的极限下,我们发现DBI宇宙弦不再是BPS,而是具有正的结合能。因此,我们认为,当它们相遇时,两个DBI弦将不会结合形成相应的结,因此DBI弦的网络很可能表现为标准宇宙弦的网络。

英文摘要:

Motivated by brane physics, we consider the non-linear Dirac-Born-Infeld (DBI) extension of the Abelian-Higgs model and study the corresponding cosmic string configurations. The model is defined by a potential term, assumed to be of the mexican hat form, and a DBI action for the kinetic terms. We show that it is a continuous deformation of the Abelian-Higgs model, with a single deformation parameter depending on a dimensionless combination of the scalar coupling constant, the vacuum expectation value of the scalar field at infinity, and the brane tension. By means of numerical calculations, we investigate the profiles of the corresponding DBI-cosmic strings and prove that they have a core which is narrower than that of Abelian-Higgs strings. We also show that the corresponding action is smaller than in the standard case suggesting that their formation could be favoured in brane models. Moreover we show that the DBI-cosmic string solutions are non-pathological everywhere in parameter space. Finally, in the limit in which the DBI model reduces to the Bogomolnyi-Prasad-Sommerfield (BPS) Abelian-Higgs model, we find that DBI cosmic strings are no longer BPS: rather they have positive binding energy. We thus argue that, when they meet, two DBI strings will not bind with the corresponding formation of a junction, and hence that a network of DBI strings is likely to behave as a network of standard cosmic strings.

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