اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدDescribing codimension two defects
100
0
0.0
(
0
)
تأليف
Aswin Balasubramanian
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
Codimension two defects of the $(0,2)$ six dimensional theory $mathscr{X}[mathfrak{j}]$ have played an important role in the understanding of dualities for certain $mathcal{N}=2$ SCFTs in four dimensions. These defects are typically understood by their behaviour under various dimensional reduction schemes. In their various guises, the defects admit partial descriptions in terms of singularities of Hitchin systems, Nahm boundary conditions or Toda operators. Here, a uniform dictionary between these descriptions is given for a large class of such defects in $mathscr{X}[mathfrak{j}], mathfrak{j} in A,D,E$.
قيم البحث
اقرأ أيضاً
One can associate an invariant to a large class of regular codimension two defects of the six dimensional $(0,2)$ SCFT $mathscr{X}[j]$ using the classical Springer correspondence. Such an association allows a simple description of S-duality of associ
ated Gaiotto-Witten boundary conditions in $mathcal{N}=4$ SYM for arbitrary gauge group and by extension, a determination of certain local aspects of class $mathcal{S}$ constructions. I point out that the problem of textit{classifying} the corresponding boundary conditions in $mathcal{N}=4$ SYM is intimately tied to possible symmetry breaking patterns in the bulk theory. Using the Springer correspondence and the representation theory of Weyl groups, I construct a pair of functors between the class of boundary conditions in the theory in the phase with broken gauge symmetry and those in the phase with unbroken gauge symmetry.
We study the localization of gravity on string-like defects in codimension two. We point out that the gravity-localizing `local cosmic string spacetime has an orbifold singularity at the horizon. The supergravity embedding and the AdS/CFT corresponde
nce suggest ways to resolve the singularity. We find two resolutions of the singularity that have a semiclassical gravity description and study their effect on the low-energy physics on the defect. The first resolution leads, at long distances, to a codimension one Randall-Sundrum scenario. In the second case, the infrared physics is like that of a conventional finite-size Kaluza-Klein compactification, with no power-law corrections to the gravitational potential. Similar resolutions apply also in higher codimension gravity-localizing backgrounds.
A six-dimensional universe with two branes in the football-shaped geometry leads to an almost realistic cosmology. We describe a family of exact solutions with time dependent characteristic size of internal space. After a short inflationary period th
e late cosmology is either of quintessence type or turns to a radiation dominated Friedmann universe where the cosmological constant appears as a free integration constant of the solution. The radiation dominated universe with relativistic fermions is analyzed in detail, including its dimensional reduction.
We discuss the possibility of a dynamical solution to the cosmological constant problem in the contaxt of six-dimensional Einstein-Maxwell theory. A definite answer requires an understanding of the full bulk cosmology in the early universe, in which
the bulk has time-dependent size and shape. We comment on the special properties of codimension two as compared to higher codimensions.
We have investigated the head-on collision of a two-kink and a two-antikink pair that arises as a generalization of the $phi^4$ model. We have evolved numerically the Klein-Gordon equation with a new spectral algorithm whose accuracy and convergence
were attested by the numerical tests. As a general result, the two-kink pair is annihilated radiating away most of the scalar field. It is possible the production of oscillons-like configurations after the collision that bounce and coalesce to form a small amplitude oscillon at the origin. The new feature is the formation of a sequence of quasi-stationary structures that we have identified as lump-like solutions of non-topological nature. The amount of time these structures survives depends on the fine-tuning of the impact velocity.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
