Igor BroeckelMichele CicoliAnshuman MaharanaKajal Singh...
12页
查看更多>>摘要：Abstract The magnitude of the vacuum expectation value of the Gukov‐Vafa‐Witten superpotential |W0|$|W_0|$ plays a central role in the phenomenology of type IIB flux compactifications. Recent analytical constructions have shown that perturbatively flat vacua can be used to obtain very low values of |W0|$|W_0|$. We present systematic algorithms to carry out exhaustive numerical searches for such vacua. We also analyse them in the statistical context, as part of the entire ensemble of type IIB flux vacua at low |W0|$|W_0|$. Our preliminary analysis indicates that these perturbatively flat vacua are statistically sparse in the whole set of vacua at low |W0|$|W_0|$ as calculated by Denef and Douglas. Two‐moduli examples are used to illustrate these more general findings in specific settings. We find that these simple (two moduli) cases are good examples for existence proofs but they do not feature a large statistical tuning freedom for phenomenological?applications.
Roberto GrimaudoAntonio Sergio Magalh?es de CastroAntonino MessinaDavide Valenti...
9页
查看更多>>摘要：Abstract We consider spin‐chain‐star systems characterized by N‐wise many‐body interactions between the spins in each chain and the central one. We show that such systems can be exactly mapped into standard spin‐star systems through unitary transformations. Such an approach allows the solution of the dynamic problem of an XX$X X$ spin‐chain‐star model and transparently shows the emergence of quantum correlations in the system, based on the idea of entanglement between?chains.
A. S. AgrawalB. MishraFrancisco Tello‐OrtizA. Alvarez...
15页
查看更多>>摘要：Abstract This work is devoted to the study of analytic wormhole solutions within the framework of f(R)$f(R)$ gravity theory. To check the possibility of having wormhole structures satisfying ?energy conditions, by means of the class I approach the pair {Φ(r),b(r)}$\lbrace \Phi (r), b(r)\rbrace$ describing the wormhole geometry has been obtained. Then, in conjunction with a remarkably f(R)$f(R)$ gravity model, the satisfaction of the null and weak energy conditions at the wormhole throat and its neighborhood is investigated. To do so, some constant parameters have been bounded restricting the space parameter. In this concern, the f(R)$f(R)$ gravity model and its derivatives are playing a major role, specially in considering the violation of the non–existence theorem. Furthermore, the shape function should be bounded from above by the Gronwall–Bellman shape function, where the red–shift function plays a relevant role. By analyzing the main properties at the spatial stations and tidal accelerations at the wormhole throat, possibilities and conditions for human travel are?explored.
查看更多>>摘要：Abstract An alternative refined de Sitter conjecture giving rise to a natural combination of the first and second derivatives of the scalar potential was proposed recently by David Andriot and Christoph Roupec (Fortsch. Phys. 67 (2019) no.1‐2, 1800105). In this work, we study the inflation models in a general scalar‐tensor theory with exponential and hyperbolic tangent forms of potential as well as model with quantum corrected potential and examine whether these three models of inflation can satisfy this further refining de Sitter swampland conjecture or not. Regarding our analysis with proper choices of parameters a,b=1?a$a, b=1- a$ and q, we find that these three inflationary models can always satisfy this new refined swampland conjecture. Therefore, all three inflationary models might all be in “landscape” since the “further refining de Sitter swampland conjecture” is?satisfied.
查看更多>>摘要：Abstract We study exceptional algebroids in the context of warped compactifications of type IIA string theory down to n dimensions, with n≤6$n\le 6$. In contrast to the M‐theory and type IIB case, the relevant algebroids are no longer exact, and their locali moduli space is no longer trivial, but has 5 distinct points. This relates to two possible scalar deformations of the IIA theory. The proof of the local classification shows that, in addition to these scalar deformations, one can twist the bracket using a pair of 1‐forms, a 2‐form, a 3‐form, and a 4‐form. Furthermore, we use the analysis to translate the classification of Leibniz parallelisable spaces (corresponding to maximally supersymmetric consistent truncations) into a tractable algebraic problem. We finish with a discussion of the Poisson–Lie U‐duality and examples given by tori and spheres in 2, 3, and 4?dimensions.
NSTL
Wiley