arXiv research

Generalizes gravitational instanton metrics to a new class.

Analogous to 4D, new Ansatz for quaternionic Kähler spaces with a free action.

We use the quaternion Kahler reduction technique to study old and new self-dual Einstein metrics of negative scalar curvature with at least a two-dimensional isometry group, and relate the quotient construction to the hyperbolic eigenfunction Ansatz. We focus in particular on the (semi-)quaternion Kahler quotients of (…

Study on curvature properties of exotic 7-sphere using quaternionic geometry.

Solves a conjecture about hyperKähler manifolds using quaternionic Monge-Ampère equation.

This article provides an explicit construction for a family of singular instantons on S^4 S^2 with arbitrary real holonomy parameter α. This family includes the original α= 1/4, c_2 = 3/2 solution discovered by P. Forgacs, Z. Horvath, and L. Palla, and our approach is modeled on that of their 1981 paper. Our primary to…

We consider a general 4n-dimensional quaternionic Kahler geometry with a free action of the torus T^(n+1). The toric action lifts onto the Swann bundle of the quaternionic Kahler space to a tri-holomorphic action that commutes with the standard H* action on the bundle. By matching Pedersen and Poon's generalized Gibbon…

It is well known that any 4-dimensional hyperkahler metric with two commuting Killing fields may be obtained explicitly, via the Gibbons-Hawking Ansatz, from a harmonic function invariant under a Killing field on R^3. In this paper, we find all selfdual Einstein metrics of nonzero scalar curvature with two commuting Ki…

We use the twistorial construction of D-instantons in Calabi-Yau compactifications of type II string theory to compute an explicit expression for the metric on the hypermultiplet moduli space affected by these non-perturbative corrections. In this way we obtain an exact quaternion-Kahler metric which is a non-trivial d…

New ansatz for generalized Kähler surfaces derived from hyperKähler ansatz.

Expressive quantum circuits are harder to train due to flatter cost landscapes.

A new approach to quantum machine learning circuits reduces training difficulties.

Deep QMC ansatzes improve variational QMC accuracy.

It was observed by Tod and later by Dunajski and Tod that the Boyer-Finley (BF) and the dispersionless Kadomtsev-Petviashvili (dKP) equations possess solutions whose level surfaces are central quadrics in the space of independent variables (the so-called central quadric ansatz). It was demonstrated that generic solutio…

A homogeneous Gibbons-Hawking ansatz is described, leading to 4-dimensional hyperkahler metrics with homotheties. In combination with Blaschke products on the unit disc in the complex plane, this ansatz allows one to construct infinite-dimensional families of such hyperkahler metrics that are, in a suitable sense, comp…

MBQC linked to CQCA, yielding efficient Ansätze.

Study of Ricci-flat metrics on C^2 with cone singularities.

We show that a complete simply-connected hyperkaehler 4-manifold with an isometric triholomorphic circle action is obtained from the Gibbons-Hawking ansatz with some suitable harmonic function.

Study Ricci flow on CP1-bundles over Kähler-Einstein manifolds.

Barrier methods classify minimal submanifolds in hyperkaehler spaces.

The modified J-flow with Calabi ansatz shows convergence or blow-up behavior based on topological constants.

Develops methods to solve complex and real Hessian equations.

Study on quaternionic bisectional curvature for quaternion-Kähler manifolds.

Constructs scalar-flat Kähler metrics with varying conical singularities.

Invariant Kähler metrics on line bundles are derived from the Calabi ansatz.

Improved Least-Squares Monte Carlo with finite-difference ansatz.

In this paper, we give the definitions and characterizations of quaternionic Salkowski, quaternionic anti-Salkowski and quaternionic similar curves in the Euclidean spaces E^3 and E^4. We obtain relationships between these curves and some special quaternionic curves such as quaternionic slant helices and quaternionic B…

The abstract discusses special Lagrangians and their flow, proving conjectures and observing related phenomena.

We construct explicit left invariant quaternionic contact structures on Lie groups with zero and non-zero torsion, and with non-vanishing quaternionic contact conformal curvature tensor, thus showing the existence of quaternionic contact manifolds not locally quaternionic contact conformal to the quaternionic sphere. W…

The quadric ansatz solves dKP equations in arbitrary dimensions, leading to Einstein-Weyl structures.

Constructs quaternionic complexes over unimodular quaternionic manifolds.

The study finds conditions for quaternionic structures on symmetric spaces.

We call a quaternionic Kaehler manifold with non-zero scalar curvature, whose quaternionic structure is trivialized by a hypercomplex structure, a hyper-Hermitian quaternionic Kaehler manifold. We prove that every locally symmetric hyper-Hermitian quaternionic Kaehler manifold is locally isometric to the quaternionic p…

We introduce a natural notion of quaternionic map between almost quaternionic manifolds and we prove the following, for maps of rank at least one: 1) A map between quaternionic manifolds endowed with the integrable almost twistorial structures is twistorial if and only if it is quaternionic. 2) A map between quaternion…

Defines quaternionic k-vector fields on quaternionic Kähler manifolds.

The paper proves quaternion projective space is unstable.

The paper studies quaternionic structures on GKM graphs and their relation to torus actions on quaternionic projective spaces.

We introduce the notion of CR quaternionic map and we prove that any such real-analytic map, between CR quaternionic manifolds, is the restriction of a quaternionic map between quaternionic manifolds. As an application, we prove, for example, that for any submanifold $M$, of dimension $4k-1$, of a quaternionic manifold…

The paper extends Gray's result to quaternion-Kähler manifolds.

Quaternionic curves with specific torsion properties don't exist.

The conformal infinity of a quaternionic-Kahler metric on a 4n-manifold with boundary is a codimension 3-distribution on the boundary called quaternionic contact. In dimensions 4n-1 greater than 7, a quaternionic contact structure is always the conformal infinity of a quaternionic-Kahler metric. On the contrary, in dim…

Study finds submaximal symmetries in almost quaternionic structures.

An ansatz of Calabi allows construction of Kahler metrics in an Hermitian disk bundle over a Kahler manifold. We attempt to give a definitive treatment of this ansatz, with the following results: We give curvature conditions on the disk bundle that guarantee existence of families of complete Kahler metrics of constant …

Quaternionic differential geometry expands geometric concepts using quaternions.

Modelled on a real hypersurface in a quaternionic manifold, we introduce a quaternionic analogue of CR structure, called quaternionic CR structure. We define the strong pseudoconvexity of this structure as well as the notion of quaternionic pseudohermitian structure. Following the construction of the Tanaka-Webster con…

The paper classifies compact affine quaternionic curves and surfaces.

We study the convergence behavior of the general inverse $σ_k$-flow on Kähler manifolds with initial metrics satisfying the Calabi Ansatz. The limiting metrics can be either smooth or singular. In the latter case, interesting conic singularities along negatively self-intersected sub-varieties are formed as a result of …

Complete Calabi-Yau metrics on C^{N+1} are constructed.