arXiv subjects

Calin Iuliu Lazaroiu

Publications and source records attributed to Calin Iuliu Lazaroiu.

34 records · Page 2Linked to original sources

arXiv2018

On B-type open-closed Landau-Ginzburg theories defined on Calabi-Yau Stein manifolds

We consider the bulk algebra and topological D-brane category arising from the differential model of the open-closed B-type topological Landau-Ginzburg theory defined by a pair $(X,W)$, where $X$ is a non-compact Calabi-Yau manifold and $W$ has compact critical set. When $X$ is a Stein manifold (but not restricted to be a domain of holomorphy), we extract equivalent descriptions of the bulk algebra and of the category of topological D-branes which are constructed using only the analytic space associated to $X$. In particular, we show that the D-brane category is described by projective matrix factorizations defined over the ring of holomorphic functions of $X$. We also discuss simplifications of the analytic models which arise when $X$ is holomorphically parallelizable and illustrate these analytic models in a few classes of examples.

math.DG↗

arXiv2018

Generalized $α$-attractor models from elementary hyperbolic surfaces

We consider generalized $α$-attractor models whose scalar potentials are globally well-behaved and whose scalar manifolds are elementary hyperbolic surfaces. Beyond the Poincaré disk $\mathbb{D}$, such surfaces include the hyperbolic punctured disk $\mathbb{D}^\ast$ and the hyperbolic annuli $\mathbb{A}(R)$ of modulus $μ=2\log R>0$. For each elementary surface, we discuss its decomposition into canonical end regions and give an explicit construction of the embedding into the Kerekjarto-Stoilow compactification (which in all cases is the unit sphere), showing how this embedding allows for a universal treatment of globally well-behaved scalar potentials upon expanding their extension in real spherical harmonics. For certain simple but natural choices of extended potentials, we compute scalar field trajectories by projecting numerical solutions of the lifted equations of motion from the Poincaré half-plane through the uniformization map, thus illustrating the rich cosmological dynamics of such models.

hep-th↗

arXiv2018

Matrix factorizations over elementary divisor domains

We study the homotopy category $\mathrm{hmf}(R,W)$ of matrix factorizations of non-zero elements $W\in R^\times$, where $R$ is an elementary divisor domain. When $R$ has prime elements and $W$ factors into a square-free element $W_0$ and a finite product of primes of multiplicity greater than one and which do not divide $W_0$, we show that $\mathrm{hmf}(R,W)$ is triangle-equivalent with an orthogonal sum of the triangulated categories of singularities $\mathrm{D}_{\mathrm sing}(A_n(p))$ of the local Artinian rings $A_n(p)=R/\langle p^n\rangle$, where $p$ runs over the prime divisors of $W$ of order $n\geq 2$. This result holds even when $R$ is not Noetherian. The triangulated categories $\mathrm{D}_{\mathrm sing}(A_n(p))$ are Krull-Schmidt and we describe them explicitly. We also study the cocycle category $\mathrm{zmf}(R,W)$, showing that it is additively generated by elementary matrix factorizations. Finally, we discuss a few classes of examples.

math.AC↗

arXiv2018

Non-degeneracy of cohomological traces for general Landau-Ginzburg models

We prove non-degeneracy of the cohomological bulk and boundary traces for general open-closed Landau-Ginzburg models associated to a pair $(X,W)$, where $X$ is a non-compact complex manifold with trivial canonical line bundle and $W$ is a complex-valued holomorphic function defined on $X$, assuming only that the critical locus of $W$ is compact (but may not consist of isolated points). These results can be viewed as certain "deformed" versions of Serre duality. The first amounts to a duality property for the hypercohomology of the sheaf Koszul complex of $W$, while the second is equivalent with the statement that a certain power of the shift functor is a Serre functor on the even subcategory of the $\mathbb{Z}_2$-graded category of topological D-branes of such models.

math.AG↗

arXiv2018

Two-field cosmological models and the uniformization theorem

We propose a class of two-field cosmological models derived from gravity coupled to non-linear sigma models whose target space is a non-compact and geometrically-finite hyperbolic surface, which provide a wide generalization of so-called $α$-attractor models and can be studied using uniformization theory. We illustrate cosmological dynamics in such models for the case of the hyperbolic triply-punctured sphere.

hep-th↗

arXiv2018

Elementary matrix factorizations over Bézout domains

We study the homotopy category $\mathrm{hef}(R,W)$ (and its $\mathbb{Z}_2$-graded version $\mathrm{HEF}(R,W)$) of elementary factorizations, where $R$ is a Bézout domain which has prime elements and $W=W_0 W_c$, where $W_0\in R^\times$ is a square-free element of $R$ and $W_c\in R^\times$ is a finite product of primes with order at least two. In this situation, we give criteria for detecting isomorphisms in $\mathrm{hef}(R,W)$ and $\mathrm{HEF}(R,W)$ and formulas for the number of isomorphism classes of objects. We also study the full subcategory $\mathbf{hef}(R,W)$ of the homotopy category $\mathrm{hmf}(R,W)$ of finite rank matrix factorizations of $W$ which is additively generated by elementary factorizations. We show that $\mathbf{hef}(R,W)$ is Krull-Schmidt and we conjecture that it coincides with $\mathrm{hmf}(R,W)$. Finally, we discuss a few classes of examples.

math.AC↗

arXiv2015

Internal circle uplifts, transversality and stratified G-structures

We study stratified G-structures in ${\cal N}=2$ compactifications of M-theory on eight-manifolds $M$ using the uplift to the auxiliary nine-manifold ${\hat M}=M\times S^1$. We show that the cosmooth generalized distribution ${\hat {\cal D}}$ on ${\hat M}$ which arises in this formalism may have pointwise transverse or non-transverse intersection with the pull-back of the tangent bundle of $M$, a fact which is responsible for the subtle relation between the spinor stabilizers arising on $M$ and ${\hat M}$ and for the complicated stratified G-structure on $M$ which we uncovered in previous work. We give a direct explanation of the latter in terms of the former and relate explicitly the defining forms of the $\mathrm{SU}(2)$ structure which exists on the generic locus ${\cal U}$ of $M$ to the defining forms of the $\mathrm{SU}(3)$ structure which exists on an open subset ${\hat {\cal U}}$ of ${\hat M}$, thus providing a dictionary between the eight- and nine-dimensional formalisms.

hep-th↗

arXiv2015

The landscape of G-structures in eight-manifold compactifications of M-theory

We consider spaces of "virtual" constrained generalized Killing spinors, i.e. spaces of Majorana spinors which correspond to "off-shell" $s$-extended supersymmetry in compactifications of eleven-dimensional supergravity based on eight-manifolds $M$. Such spaces naturally induce two stratifications of $M$, called the chirality and stabilizer stratification. For the case $s=2$, we describe the former using the canonical Whitney stratification of a three-dimensional semi-algebraic set ${\cal R}$. We also show that the stabilizer stratification coincides with the rank stratification of a cosmooth generalized distribution ${\cal D}_0$ and describe it explicitly using the Whitney stratification of a four-dimensional semi-algebraic set $\mathfrak{P}$. The stabilizer groups along the strata are isomorphic with $\mathrm{SU}(2)$, $\mathrm{SU}(3)$, $\mathrm{G}_2$ or $\mathrm{SU}(4)$, where $\mathrm{SU(2)}$ corresponds to the open stratum, which is generically non-empty. We also determine the rank stratification of a larger generalized distribution ${\cal D}$ which turns out to be integrable in the case of compactifications down to $\mathrm{AdS}_3$.

hep-th↗

arXiv2015

Singular foliations for M-theory compactification

We use the theory of singular foliations to study ${\cal N}=1$ compactifications of eleven-dimensional supergravity on eight-manifolds $M$ down to $\mathrm{AdS}_3$ spaces, allowing for the possibility that the internal part $ξ$ of the supersymmetry generator is chiral on some locus ${\cal W}$ which does not coincide with $M$. We show that the complement $M\setminus {\cal W}$ must be a dense open subset of $M$ and that $M$ admits a singular foliation ${\bar {\cal F}}$ endowed with a longitudinal $G_2$ structure and defined by a closed one-form $\boldsymbolω$, whose geometry is determined by the supersymmetry conditions. The singular leaves are those leaves which meet ${\cal W}$. When $\boldsymbolω$ is a Morse form, the chiral locus is a finite set of points, consisting of isolated zero-dimensional leaves and of conical singularities of seven-dimensional leaves. In that case, we describe the topology of ${\bar {\cal F}}$ using results from Novikov theory. We also show how this description fits in with previous formulas which were extracted by exploiting the $\mathrm{Spin}(7)_\pm$ structures which exist on the complement of ${\cal W}$.

hep-th↗

arXiv2015

Foliated backgrounds for M-theory compactifications (I)

We summarize our geometric and topological description of compact eight-manifolds which arise as internal spaces in ${\cal N}=1$ flux compactifications of M-theory down to $\mathrm{AdS}_3$, under the assumption that the internal part of the supersymmetry generator is everywhere non-chiral. Specifying such a supersymmetric background is {\em equivalent} with giving a certain codimension one foliation defined by a closed one-form and which carries a leafwise $G_2$ structure, a foliation whose topology and geometry we characterize rigorously.

hep-th↗

arXiv2015

Foliated eight-manifolds for M-theory compactification

We characterize compact eight-manifolds M which arise as internal spaces in N=1 flux compactifications of M-theory down to AdS3 using the theory of foliations, for the case when the internal part of the supersymmetry generator is everywhere non-chiral. We prove that specifying such a supersymmetric background is equivalent with giving a codimension one foliation of M which carries a leafwise G2 structure, such that the O'Neill-Gray tensors, non-adapted part of the normal connection and torsion classes of the G2 structure are given in terms of the supergravity four-form field strength by explicit formulas which we derive. We discuss the topology of such foliations, showing that the C star algebra of the foliation is a noncommutative torus of dimension given by the irrationality rank of a certain cohomology class constructed from the four-form field strength, which must satisfy the Latour obstruction. We also give a criterion in terms of this class for when such foliations are fibrations over the circle. When the criterion is not satisfied, each leaf of the foliation is dense in M.

hep-th↗

arXiv2014

A generalization of Calabi-Yau fourfolds arising from M-theory compactifications

Using a reconstruction theorem, we prove that the supersymmetry conditions for a certain class of flux backgrounds are equivalent with a tractable subsystem of relations on differential forms which encodes the full set of contraints arising fom Fierz identities and from the differential and algebraic conditions on the internal part of the supersymmetry generators. The result makes use of the formulation of such problems through Kähler-Atiyah bundles, which we developed in previous work. Applying this to the most general ${\cal N}=2$ flux compactifications of 11-dimensional supergravity on 8-manifolds, we can extract the conditions constraining such backgrounds and give an overview of the resulting geometry, which generalizes that of Calabi-Yau fourfolds.

hep-th↗

arXiv2013

A unified approach to Fierz identities

We summarize a unified and computationally efficient treatment of Fierz identities for form-valued pinor bilinears in various dimensions and signatures, using concepts and techniques borrowed from a certain approach to spinors known as geometric algebra. Our formulation displays the real, complex and quaternionic structures in a conceptually clear manner, which is moreover amenable to implementation in various symbolic computation systems.

hep-th↗

arXiv2013

Geometric algebra and M-theory compactifications

We show how supersymmetry conditions for flux compactifications of supergravity and string theory can be described in terms of a flat subalgebra of the Kahler-Atiyah algebra of the compactification space, a description which has wide-ranging applications. As a motivating example, we consider the most general M-theory compactifications on eight-manifolds down to AdS3 spaces which preserve N=2 supersymmetry in 3 dimensions. We also give a brief sketch of the lift of such equations to the cone over the compactification space and of the geometric algebra approach to `constrained generalized Killing pinors', which forms the technical and conceptual core of our investigation.

hep-th↗

arXiv2009

Generalized Berezin-Toeplitz quantization of Kaehler supermanifolds

We extend the construction of generalized Berezin and Berezin-Toeplitz quantization to the case of compact Hodge supermanifolds. Our approach is based on certain super-analogues of Rawnsley's coherent states. As applications, we discuss the quantization of affine and projective superspaces. Furthermore, we propose a definition of supersymmetric sigma-models on quantized Hodge supermanifolds. The corresponding quantum field theories are finite and thus yield supersymmetry-preserving regularizations for QFTs defined on flat superspace.

hep-th↗

arXiv2008

Generalized Berezin quantization, Bergman metrics and fuzzy Laplacians

We study extended Berezin and Berezin-Toeplitz quantization for compact Kaehler manifolds, two related quantization procedures which provide a general framework for approaching the construction of fuzzy compact Kaehler geometries. Using this framework, we show that a particular version of generalized Berezin quantization, which we baptize "Berezin-Bergman quantization", reproduces recent proposals for the construction of fuzzy Kaehler spaces. We also discuss how fuzzy Laplacians can be defined in our general framework and study a few explicit examples. Finally, we use this approach to propose a general explicit definition of fuzzy scalar field theory on compact Kaehler manifolds.

hep-th↗