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arXiv research

A locally-built, LLM-digested index of recent arXiv papers in quant finance, geometry/topology, and statistical ML — keyword search served straight from SQLite on this machine.

168,657 papers · 148 categories

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3146289421,256 · Jun 202019922001200920172026
48 results for Unitary Kernel Method

The starting point of our analysis is an old idea of writing an eigenfunction expansion for a heat kernel considered in the case of a hypoelliptic heat kernel on a nilpotent Lie group GG. One of the ingredients of this approach is the generalized Fourier transform. The formula one gets using this approach is explicit …

2015-05-15abs ↗pdf ↗

Develops noncommutative Cowen-Douglas theory for noncommuting operators.

problem Exploring noncommutative analogues of classical Cowen-Douglas theory.
method Defining noncommutative Cowen-Douglas class using matricial joint eigenvalues and showing equivalence classes are determined by associated noncommutative vector bundles.
result Unitary equivalence class of a tuple in the noncommutative Cowen-Douglas class is determined by the equivalence class of its associated noncommutative vector bundle.

Classifies and constructs intertwining differential operators between vector bundles over real projective space.

problem Classifying and constructing intertwining differential operators between vector bundles over RP2\mathbb{RP}^2.
method Utilizes SL(3,R)SL(3,\mathbb{R})-intertwining differential operators, BGG resolution, and representation theory.
result Irreducible unitary highest weight modules of SU(1,2)SU(1,2) at reduction points classified by Cartan and PRV operators.

Efficient diffusion model for symmetric manifolds reduces training and computation costs.

problem Heat kernel computations for manifold diffusion models are computationally expensive and infeasible.
method Spatially-varying covariance diffusion model, efficient objective derived via Ito's Lemma.
result Our model reduces training time and arithmetic operations by orders of magnitude.

Study of unitary and groupoid orbits of normal operators, focusing on manifold structures and spectral conditions.

problem Understanding the manifold structures of orbits of normal operators under different norm topologies.
method Unified treatment of unitary and groupoid orbits, using moment maps and conditional expectations.
result Differentiable structures for orbits and necessary spectral conditions for norm closure and submanifold properties.

We prove that the kernels of the restrictions of symplectic Dirac or symplectic Dirac-Dolbeault operators on natural subspaces of polynomial valued spinor fields are finite dimensional on a compact symplectic manifold. We compute those kernels for the complex projective spaces. We construct injections of subgroups of t…

2013-07-05abs ↗pdf ↗

We give in explicit form the principal kinematic formula for the action of the affine unitary group on $\C^n$, together with a straightforward algebraic method for computing the full array of unitary kinematic formulas, expressed in terms of certain convex valuations introduced, essentially, by H. Tasaki. We introduce …

2008-01-04abs ↗pdf ↗

Extends Mahalanobis distance to Banach spaces for anomaly detection.

problem Anomaly detection in infinite-dimensional spaces.
method Generalizes Mahalanobis distance to Banach spaces via Cameron-Martin norm and variance norm.
result Kernelized nearest-neighbour Mahalanobis distance outperforms traditional methods for time series novelty detection.

We develop a novel Gaussian process method for manifold data.

problem Challenges in Gaussian processes on manifold-based predictors, especially in high dimensions.
method Intrinsic approach for constructing Gaussian processes on general manifolds, using the exponential map for heat kernel estimation.
result Remarkable efficiency gains and applicability to high-dimensional manifolds.

Topological quantum computation with Fibonacci anyons relies on the possibility of efficiently generating unitary transformations upon pseudoparticles braiding. The crucial fact that such set of braids has a dense image in the unitary operations space is well known; in addition, the Solovay-Kitaev algorithm allows to a…

2008-01-18abs ↗pdf ↗

We formulate the unitary rational orbifold conformal field theories in the algebraic quantum field theory framework. Under general conditions, we show that the orbifold of a given unitary rational conformal field theories generates a unitary modular category. Many new unitary modular categories are obtained. We also sh…

2000-04-24abs ↗pdf ↗

Study on learning quantum dynamics without direct interaction.

problem Learning quantum dynamics incoherently without direct interaction.
method Analyze sample complexity and prove bounds for incoherent learning.
result Prove that arbitrary measurements allow efficient learning of unitary processes incoherently.

Quantum-assisted Gaussian process speeds up data regression.

problem High computational complexity of Gaussian process regression for large datasets.
method Quantum-assisted sparse Gaussian process regression using random Fourier features.
result Achieves polynomial-order computational speedup compared to classical methods.

Recurrent neural networks are powerful models for processing sequential data, but they are generally plagued by vanishing and exploding gradient problems. Unitary recurrent neural networks (uRNNs), which use unitary recurrence matrices, have recently been proposed as a means to avoid these issues. However, in previous …

2016-10-31abs ↗pdf ↗

Study on determinants of unitary Brownian motion and their asymptotic laws.

problem Understanding determinants of unitary Brownian motion and their behavior over time.
method Using Stiefel fibration and skew-product decomposition of the Stiefel Brownian motion.
result Prove asymptotic laws for determinants of block entries of unitary Brownian motion.

We construct a new family of toric manifolds generating the unitary bordism ring. Each manifold in the family is the complex projectivisation of the sum of a line bundle and a trivial bundle over a complex projective space. We also construct a family of special unitary quasitoric manifolds which contains polynomial gen…

2014-12-16abs ↗pdf ↗

For a compact surface S=Sg,nS = S_{g,n} with 3g+n43g + n \geq 4, we introduce a family of unitary representations of the mapping class group Mod(SS) based on the space of measured foliations. For this family of representations, we show that none of them has almost invariant vectors. As one application, we obtain an inequalit…

2019-06-04abs ↗pdf ↗

Study circle actions on unitary manifolds with discrete fixed points.

problem Understanding circle actions on compact unitary manifolds with discrete fixed points.
method Prove relationships between weights at fixed points and derive results regarding the first equivariant Chern class and Hirzebruch χyχ_y-genus.
result Derive a multigraph encoding fixed point data, leading to new insights into unitary S1S^1-manifolds.

A major challenge in the training of recurrent neural networks is the so-called vanishing or exploding gradient problem. The use of a norm-preserving transition operator can address this issue, but parametrization is challenging. In this work we focus on unitary operators and describe a parametrization using the Lie al…

2016-07-17abs ↗pdf ↗

The study shows ergodicity of unitary frame flows on Kähler manifolds with specific curvature conditions.

problem Ergodicity of unitary frame flows on Kähler manifolds with negative holomorphic sectional curvature.
method Analysis of the unitary frame flow on the principal U(m)-bundle of unitary frames.
result For even-dimensional Kähler manifolds with negative λ(m)-pinched holomorphic sectional curvature, the unitary frame flow is ergodic and mixing.

We propose a method to assign non-unitary TQFTs to certain SCFTs, deriving bounds and examples.

problem Assigning non-unitary TQFTs to specific SCFTs of rank 0.
method Using degenerate limits of SCFTs, extracting modular data from supersymmetric partition functions, and proposing a dictionary.
result Deriving a lower bound on the free energy of SCFTs and showing it is saturated by a specific SCFT.

With the usual definition of a super Hilbert space and a super unitary representation, it is easy to show that there are lots of super Lie groups for which the left-regular representation is not super unitary. I will argue that weakening the definition of a super Hilbert space (by allowing the super scalar product to b…

2017-11-01abs ↗pdf ↗

This paper introduces a submanifold of the moduli space of unitary representations of the fundamental group of a punctured sphere with fixed local monodromy. The submanifold is defined via products of involutions through Lagrangian subspaces. We show that the moduli space of Lagrangian representations is a Lagrangian s…

2005-06-06abs ↗pdf ↗

Researchers describe unitary representations of mixed braid groups.

problem Understanding unitary representations of mixed braid groups.
method Explicitly describe unitary representations on cohomology of Abelian branched covers.
result Image of the representation is generated by complex reflections and related to the multivariate Burau representation.

Let Uc(H)=u:uisunitaryandu1iscompactU_c(H)={u: u is unitary and u-1 is compact} stand for the unitary Fredholm group. We prove the following convexity result. Denote by dd_\infty the rectifiable distance induced by the Finsler metric given by the operator norm in Uc(H)U_c(H). If u0,u1,uUc(H)u_0,u_1,u\in U_c(H) and the geodesic ββ joining u0u_0 and u1u_1 in $U…

2008-12-24abs ↗pdf ↗

Researchers extend geometric quantization to complex Abelian Lie supergroups.

problem Quantization of super Kähler structures on complex Abelian Lie supergroups.
method Extended geometric quantization scheme to super Kähler setting, constructed unitary representation.
result Irreducible subrepresentations of the constructed representation are determined by the moment map.

Unitary recurrent neural networks (URNNs) have been proposed as a method to overcome the vanishing and exploding gradient problem in modeling data with long-term dependencies. A basic question is how restrictive is the unitary constraint on the possible input-output mappings of such a network? This work shows that for …

2019-10-30abs ↗pdf ↗

Curious structure of special orthogonal, unitary, and symplectic groups as products of Grassmannians discovered.

problem Understanding the structure of special orthogonal, unitary, and symplectic groups.
method Expressing these groups as products of Grassmannians realized as involution matrices.
result Special orthogonal, special unitary, and symplectic groups can be expressed as products of their corresponding Grassmannians.

This is a second paper in a series devoted to the minimal unitary representation of O(p,q). By explicit methods from conformal geometry of pseudo-Riemannian manifolds, we find the branching law corresponding to restricting the minimal unitary representation to natural symmetric subgroups. In the case of purely discrete…

2001-11-07abs ↗pdf ↗