اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدThe One-Loop H^2R^3 and H^2(DH)^2R Terms in the Effective Action
323
0
0.0
(
0
)
تأليف
David M. Richards
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
We consider the one-loop B^2h^3 and B^4h amplitudes in type II string theory, where B is the NS-NS two-form and h the graviton, and expand to lowest order in alpha. After subtracting diagrams due to quartic terms in the effective action, we determine the presence and structure of both an H^2R^3 and H^2(DH)^2R term. We show that both terms are multiplied by the usual (t_8t_8pm{1/8}epsilon_{10}epsilon_{10}) factor.
قيم البحث
اقرأ أيضاً
We consider the one-loop five-graviton amplitude in type II string theory calculated in the light-cone gauge. Although it is not possible to explicitly evaluate the integrals over the positions of the vertex operators, a low-energy expansion can be o
btained, which can then be used to infer terms in the low-energy effective action. After subtracting diagrams due to known D^{2n}R^4 terms, we show the absence of one-loop R^5 and D^2R^5 terms and determine the exact structure of the one-loop D^4R^5 terms where, interestingly, the coefficient in front of the D^4R^5 terms is identical to the coefficient in front of the D^6R^4 term. Finally, we show that, up to D^6R^4 ~ D^4R^5, the epsilon_{10} terms package together with the t_8 terms in the usual combination (t_8t_8pm{1/8}epsilon_{10}epsilon_{10}).
Recent development of path integral matching techniques based on the covariant derivative expansion has made manifest a universal structure of one-loop effective Lagrangians. The universal terms can be computed once and for all to serve as a referenc
e for one-loop matching calculations and to ease their automation. Here we present the fermionic universal one-loop effective action (UOLEA), resulting from integrating out heavy fermions with scalar, pseudo-scalar, vector and axial-vector couplings. We also clarify the relation of the new terms computed here to terms previously computed in the literature and those that remain to complete the UOLEA. Our results can be readily used to efficiently obtain analytical expressions for effective operators arising from heavy fermion loops.
We propose TBA integral equations for 1-particle states in the O(n) non-linear sigma-model for even n. The equations are conjectured on the basis of the analytic properties of the large volume asymptotics of the problem, which is explicitly construct
ed starting from Luschers asymptotic formula. For small volumes the mass gap values computed numerically from the TBA equations agree very well with results of three-loop perturbation theory calculations, providing support for the validity of the proposed TBA system.
We review and present full detail of the Feynman diagram - based and heat-kernel method - based calculations of the simplest nonlocal form factors in the one-loop contributions of a massive scalar field. The paper has a pedagogical and introductory p
urposes and is intended to help the reader in better understanding the existing literature on the subject. The functional calculations are based on the solution by Avramidi and Barvinsky & Vilkovisky for the heat kernel and are performed in curved spacetime. One of the important points is that the main structure of non-localities is the same as in the flat background.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
