1. Statistics of limit root bundles relevant for exact matter spectra of F-theory MSSMsMartin Bies, Mirjam Cvetič, Mingqiang Liu, 2021, izvirni znanstveni članek Opis: In the largest, currently known, class of one quadrillion globally consistent F-theory Standard Models with gauge coupling unification and no chiral exotics, the vectorlike spectra are counted by cohomologies of root bundles. In this work, we apply a previously proposed method to identify toric base threefolds, which are promising to establish F-theory Standard Models with exactly three quark doublets and no vectorlike exotics in this representation. The base spaces in question are obtained from triangulations of 708 polytopes. By studying root bundles on the quark-doublet curve Cð3;2Þ1=6 and employing well-known results about desingularizations of toric K3 surfaces, we derive a triangulation independent lower bound Nˇ ð3Þ P for the number Nð3Þ P of root bundles on Cð3;2Þ1=6 with exactly three sections. The ratio Nˇ ð3Þ P =NP, where NP is the total number of roots on Cð3;2Þ1=6 , is largest for base spaces associated with triangulations of the eighth three-dimensional polytope Δ∘ 8 in the Kreuzer-Skarke list. For each of these Oð1015Þ threefolds, we expect that many root bundles on Cð3;2Þ1=6 are induced from F-theory gauge potentials and that at least every 3000th root on Cð3;2Þ1=6 has exactly three global sections and thus no exotic vectorlike quark-doublet modes. Ključne besede: astrophysics, compactification, string theory models, geometry, higher-dimensional field theories, mathematical physics, quantum fields in curved spacetime, string phenomenology, supersymmetric models, topology Objavljeno v DKUM: 16.10.2023; Ogledov: 207; Prenosov: 11 Celotno besedilo (444,13 KB) Gradivo ima več datotek! Več... |
2. Gauge group topology of 8D Chaudhuri-Hockney-Lykken vacuaMirjam Cvetič, Markus Dierigl, Ling Lin, Hao Y. Zhang, 2021, izvirni znanstveni članek Opis: Compactifications of the Chaudhuri-Hockney-Lykken (CHL) string to eight dimensions can be characterized by embeddings of root lattices into the rank 12 momentum lattice ΛM, the so-called Mikhailov lattice. Based on these data, we devise a method to determine the global gauge group structure including all Uð1Þ factors. The key observation is that, while the physical states correspond to vectors in the momentum lattice, the gauge group topology is encoded in its dual. Interpreting a nontrivial π1ðGÞ ≡ Z for the non-Abelian gauge group G as having gauged a Z 1-form symmetry, we also prove that all CHL gauge groups are free of a certain anomaly [1] that would obstruct this gauging. We verify this by explicitly computing Z for all 8D CHL vacua with rankðGÞ ¼ 10. Since our method applies also to T2 compactifications of heterotic strings, we further establish a map that determines any CHL gauge group topology from that of a “parent” heterotic model. Ključne besede: astrophysics, compactification, string dualities, string and branes, discrete symmetries, symmetries, gauge symmetries Objavljeno v DKUM: 13.10.2023; Ogledov: 338; Prenosov: 13 Celotno besedilo (356,95 KB) Gradivo ima več datotek! Več... |
3. Higher-form symmetries and their anomalies in M-/F-theory dualityMirjam Cvetič, Markus Dierigl, Ling Lin, Hao Y. Zhang, 2021, izvirni znanstveni članek Opis: We explore higher-form symmetries of M- and F-theory compactified on elliptic fibrations, determined by the topology of their asymptotic boundaries. The underlying geometric structures are shown to be equivalent to known characterizations of the gauge group topology in F-theory via Mordell-Weil torsion and string junctions. We further study dimensional reductions of the 11d Chern-Simons term in the presence of torsional boundary G4-fluxes, which encode background gauge fields of center one-form symmetries in the lower-dimensional effective gauge theory. We find contributions that can be interpreted as ’t Hooft anomalies involving the one-form symmetry which originate from a fractionalization of the instanton number of non-Abelian gauge theories in F-/M-theory compactifications to 8d=7d and 6d=5d. Ključne besede: astrophysics, anomalies, compactification, M-theory, string dualities, discrete symmetries, symmetries Objavljeno v DKUM: 13.10.2023; Ogledov: 338; Prenosov: 4 Celotno besedilo (752,29 KB) Gradivo ima več datotek! Več... |
4. Rotating solutions in critical Lovelock gravitiesMirjam Cvetič, Xing-Hui Feng, Hong Lü, Christopher N. Pope, 2017, izvirni znanstveni članek Opis: For appropriate choices of the coupling constants, the equations of motion of Lovelock gravities up to order n in the Riemann tensor can be factorized such that the theories admit a single (A)dS vacuum. In this paper we construct two classes of exact rotating metrics in such critical Lovelock gravities of order n in d = 2n +1 dimensions. In one class, the n angular momenta in the n orthogonal spatial 2-planes are equal, and hence the metric is of cohomogeneity one. We construct these metrics in a Kerr-Schild form, but they can then be recast in terms of Boyer-Lindquist coordinates. The other class involves metrics with only a single non-vanishing angular momentum. Again we construct them in a Kerr-Schild form, but in this case it does not seem to be possible to recast them in Boyer-Lindquist form. Both classes of solutions have naked curvature singularities, arising because of the over rotation of the configurations. Ključne besede: astrophysics, nuclear physics Objavljeno v DKUM: 08.03.2018; Ogledov: 2003; Prenosov: 424 Celotno besedilo (274,39 KB) Gradivo ima več datotek! Več... |