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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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48 results for matrix densities

Paper proposes a new approach to optimal transport for vector and matrix densities.

problem Optimal transport for vector and matrix densities with positivity and action transitivity constraints.
method Gauge-theoretic approach using semi-direct product groups of diffeomorphisms and gauge transformations.
result Bures-type metrics on semi-direct product groups relate to Wasserstein-type metrics on vector and matrix densities via Riemannian submersions.

We introduce two methods for estimating the density matrix for a quantum system: Quantum Maximum Likelihood and Quantum Variational Inference. In these methods, we construct a variational family to model the density matrix of a mixed quantum state. We also introduce quantum flows, the quantum analog of normalizing flow…

2019-04-11abs ↗pdf ↗

New method improves sampling from high-dimensional target densities.

problem Sampling from high-dimensional target densities using Monte Carlo algorithms.
method Extends Metropolis-Adjusted Langevin Diffusion algorithm with random precondition matrix modeling.
result Significantly improves performance and computational efficiency over standard MCMC methods.

Incorporates matrix exponential into generative flows for improved performance.

problem Improving generative flow models for better density estimation.
method Integrates matrix exponential into generative flows, proposing new layers and modifying network architecture.
result The proposed model achieves great performance on density estimation.

Spectral density matrix estimation of multivariate time series is a classical problem in time series and signal processing. In modern neuroscience, spectral density based metrics are commonly used for analyzing functional connectivity among brain regions. In this paper, we develop a non-asymptotic theory for regularize…

2018-12-03abs ↗pdf ↗

We describe a method to determine the eigenvalue density of empirical covariance matrix in the presence of correlations between samples. This is a straightforward generalization of the method developed earlier by the authors for uncorrelated samples. The method allows for exact determination of the experimental spectru…

2005-08-19abs ↗pdf ↗

Proposes a framework to balance supervised and unsupervised learning using random matrix theory.

problem Balancing supervised and unsupervised learning in high-dimensional data.
method QLDS model with quadratic margin maximization under low density separation assumption.
result Establishes a smooth bridge between supervised and unsupervised learning methods.

The Sinkhorn-Knopp algorithm converges quickly but the number of iterations is poorly understood.

problem Understanding the number of iterations required for the Sinkhorn-Knopp algorithm to converge.
method Analyzing the Sinkhorn-Knopp algorithm for matrices with a specific density threshold.
result The Sinkhorn-Knopp algorithm requires Ω(n1/2/ε)Ω(n^{1/2}/\varepsilon) iterations for matrices with density γ<1/2γ<1/2.

New trust matrix quantifies breakdowns in deep neural networks.

problem Understanding trust breakdowns in deep learning models.
method Introduces trust matrix and conditional trust densities to analyze deep neural networks.
result Trust matrices reveal areas needing improvement for deep neural networks.

We provide a method to prepare covariance matrices for quantum datasets.

problem No concrete protocol for preparing covariance matrices for quantum datasets.
method Amplitude encoding of data, exploiting global phase symmetry to center the dataset.
result Covariance matrix can be prepared for arbitrary quantum datasets or centered classical datasets.

New machine learning method detects quantum separability in large-scale systems.

problem Deciding quantum separability of large-scale bipartite density matrices.
method Frank-Wolfe-based algorithm for finding nearest separable density matrices and classification of density matrices as separable or entangled.
result The method scales up to thousands of density matrices and achieves high quantum entanglement detection accuracy.

This work explores efficient reinforcement learning with density features in low-rank MDPs.

problem Efficient reinforcement learning with density features in low-rank MDPs.
method Proposes algorithms for off-policy estimation and online construction of exploratory data distributions.
result Demonstrates sample-efficient learning with density features in low-rank MDPs, overcoming technical challenges.

Interactive privacy mechanisms improve spectral density estimation under local differential privacy.

problem Estimating spectral density of Gaussian time series with local differential privacy constraints.
method Two-stage process: Laplace mechanism followed by privatized sample analysis.
result Interactive mechanisms achieve faster rates for spectral density estimation.

Improved singular value approximation for convolutional layers.

problem Improving accuracy of singular value approximation for linear convolutional layers.
method Developed a new spectral density matrix method for singular value approximation with improved accuracy and reduced computational complexity.
result Obtained moderate improvement in singular value distribution compared to circular approximation.

Proposes a new method for kernel density estimation using stagewise minimization and a simple dictionary.

problem Kernel density estimation with data-adaptive weighting parameters and sparse representation.
method Stagewise minimization algorithm based on UU-divergence and a simple dictionary.
result Develops non-asymptotic error bound for the proposed estimator.

A new clustering algorithm reduces density peaks clustering's computational complexity.

problem High computational complexity of density peaks clustering.
method Sparse distance matrix, sparse search, K-d tree, second-order difference method.
result Reduced computational complexity from O(n2K)O(n^2K) to O(n(n11/K+k))O(n(n^{1-1/K}+k)).

Method interpolates option prices and volatilities without arbitrage.

problem Interpolating option prices and volatilities without arbitrage.
method Sparse modeling approach based on integral equations and SVD.
result Flexible and efficient framework for arbitrage-free interpolation.

A new machine learning model uses score matching to estimate probability densities efficiently.

problem Estimating probability density functions is challenging.
method Introduced a product Jacobi-Theta Boltzmann machine (pJTBM) and used score matching for efficient fitting.
result The pJTBM can fit probability densities more efficiently than the RTBM using score matching.

Let Sm{\mathcal S}_m be the set of all m×mm\times m density matrices (Hermitian positively semi-definite matrices of unit trace). Consider a problem of estimation of an unknown density matrix ρSmρ\in {\mathcal S}_m based on outcomes of nn measurements of observables X1,,XnHmX_1,\dots, X_n\in {\mathbb H}_m (Hm{\mathbb H}_m bei…

2016-04-15abs ↗pdf ↗

Following Hartigan, a cluster is defined as a connected component of the t-level set of the underlying density, i.e., the set of points for which the density is greater than t. A clustering algorithm which combines a density estimate with spectral clustering techniques is proposed. Our algorithm is composed of two step…

2010-02-11abs ↗pdf ↗

Generative source separation methods such as non-negative matrix factorization (NMF) or auto-encoders, rely on the assumption of an output probability density. Generative Adversarial Networks (GANs) can learn data distributions without needing a parametric assumption on the output density. We show on a speech source se…

2017-10-30abs ↗pdf ↗

We apply random matrix theory to derive spectral density of large sample covariance matrices generated by multivariate VMA(q), VAR(q) and VARMA(q1,q2) processes. In particular, we consider a limit where the number of random variables N and the number of consecutive time measurements T are large but the ratio N/T is fix…

2010-02-04abs ↗pdf ↗

A regression algorithm uses Green's function and covariance matrix for predictive distributions.

problem Regression and uncertainty quantification for machine learning.
method Green's function theory, Bayesian approach, covariance matrix of normalized Green's function.
result The covariance matrix provides predictive distributions with mean and confidence intervals.

The paper connects Riemannian Gaussian distributions to random matrix theory and diffusion kernels.

problem Analyzing Riemannian Gaussian distributions on symmetric spaces.
method Analytical computation of marginals using orthogonal and skew orthogonal polynomials, and diffusion kernels.
result Riemannian Gaussian distributions are random matrix types, and their probability density functions can be computed analytically.

Density matrices are positively semi-definite Hermitian matrices with unit trace that describe the states of quantum systems. Many quantum systems of physical interest can be represented as high-dimensional low rank density matrices. A popular problem in {\it quantum state tomography} (QST) is to estimate the unknown l…

2016-10-16abs ↗pdf ↗

FSPA bypasses eigenvalue estimation for quantum PCA, achieving optimal complexity and robustness.

problem Quantum PCA eigenvalue estimation is computationally expensive and prone to errors.
method Filtered Spectral Projection Algorithm (FSPA) that projects onto the dominant spectral subspace directly.
result FSPA achieves optimal complexity and robustness, outperforming classical methods.

Graph diffusion processes approximate manifold heat semigroups using graph transition matrices.

problem Approximating manifold heat semigroups from graph data under low regularity conditions.
method Iterating graph transition matrix PP to approximate Qt=etΔQ_t = e^{tΔ}, bounding error in \infty-norm.
result Convergence rates O(N2/(d+6))O(N^{-2/(d+6)}) for manifold heat semigroup approximation, valid for in-sample and out-of-sample.

The ratio of two probability densities can be used for solving various machine learning tasks such as covariate shift adaptation (importance sampling), outlier detection (likelihood-ratio test), and feature selection (mutual information). Recently, several methods of directly estimating the density ratio have been deve…

2009-12-15abs ↗pdf ↗

Kernel density matrices simplify probabilistic deep learning.

problem Representing joint probability distributions of continuous and discrete variables.
method Extending density matrices to a reproducing kernel Hilbert space.
result Versatile representation for marginal and joint probability distributions.