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Matter evolved under influence of gravity from minuscule density fluctuations. Non-perturbative structure formed hierarchically over all scales, and developed non-Gaussian features in the Universe, known as the Cosmic Web. To fully…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-01 Siyu He , Yin Li , Yu Feng , Shirley Ho , Siamak Ravanbakhsh , Wei Chen , Barnabás Póczos

Optimally resolved one-dimensional density and velocity profiles through cosmological N-body simulations are constructed by means of the Voronoi-Delaunay tessellation reconstruction technique. In a fully self-adaptive fashion a strikingly…

Astrophysics · Physics 2007-05-23 W. E. Schaap , R. van de Weygaert

The distribution of matter that is measured through galaxy redshift and peculiar velocity surveys can be harnessed to learn about the physics of dark matter, dark energy, and the nature of gravity. To improve our understanding of the matter…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-04 Fei Qin , David Parkinson , Sungwook E. Hong , Cristiano G. Sabiu

We describe a novel end-to-end approach using Machine Learning to reconstruct the power spectrum of cosmological density perturbations at high redshift from observed quasar spectra. State-of-the-art cosmological simulations of structure…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-21 Maria Han Veiga , Xi Meng , Oleg Y. Gnedin , Nickolay Y. Gnedin , Xun Huan

We reconstruct the dark matter density field from spatially overlapping spectroscopic and photometric redshift catalogs through a forward modelling approach. Instead of directly inferring the underlying density field, we find the best…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-01 Benjamin Horowitz , Peter Melchior

General exact solution is obtained for the problem of the development of arbitrary disturbances of the density and velocity in a (1+1)-dimensional universe. This analytical solution may serve, particularly, as a test for numerical methods.…

General Physics · Physics 2010-01-22 E. A. Novikov

We consider state reconstruction from the measurement statistics of phase space observables generated by photon number states. The results are obtained by inverting certain infinite matrices. In particular, we obtain reconstruction…

Quantum Physics · Physics 2010-02-11 Jukka Kiukas , Juha-Pekka Pellonpää , Jussi Schultz

We present a first principle approach to obtain analytical predictions for spherically-averaged cosmic densities in the mildly non-linear regime that go well beyond what is usually achieved by standard perturbation theory. A large deviation…

Cosmology and Nongalactic Astrophysics · Physics 2016-05-25 Cora Uhlemann , Sandrine Codis , Christophe Pichon , Francis Bernardeau , Paulo Reimberg

For many analyses in cosmology it is necessary to reconstruct the likely distribution of unobserved fields, such as dark matter or non-luminous baryons, from observed luminous tracers. The dominant approach in cosmology has been to use the…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-16 Jordan Krywonos , Yurii Kvasiuk , Matthew C. Johnson , Moritz Münchmeyer

In this paper, we show numerically that a symmetric Earth matter density profile can, in principle, be reconstructed from a single baseline energy spectrum up to a certain precision. For the numerical evaluations in the high dimensional…

High Energy Physics - Phenomenology · Physics 2009-11-07 Tommy Ohlsson , Walter Winter

We apply an iterative reconstruction method to galaxy mocks in redshift space obtained from $N$-body simulations. Comparing the two-point correlation functions for the reconstructed density field, we find that although the performance is…

Cosmology and Nongalactic Astrophysics · Physics 2019-06-26 Ryuichiro Hada , Daniel J. Eisenstein

The interstellar medium (ISM) exhibits complex, multi-scale structures that are challenging to study due to their projection into two-dimensional (2D) column density maps. We present the Volume Density Mapper, a novel algorithm based on…

Instrumentation and Methods for Astrophysics · Physics 2025-09-23 Guang-Xing Li , Mengke Zhao

Nonlinear gravitational evolution induces strong nonlinearities in the observed cosmological density fields, leading to positive off-diagonal correlations in the power spectrum covariance. This has caused the information saturation in the…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-29 Shi-Hui Zang , Hong-Ming Zhu

We propose a novel model for nonlinear dimension reduction motivated by the probabilistic formulation of principal component analysis. Nonlinearity is achieved by specifying different transformation matrices at different locations of the…

Computer Vision and Pattern Recognition · Computer Science 2008-02-12 Heng Lian

The problem of determining three-dimensional density fields from single two-dimensional projections is hopelessly underdetermined without additional assumptions. While parameterized inversions are typically used to solve this problem, we…

Dynamical Systems · Mathematics 2007-05-23 Kevin R. Vixie , Gary L. Sandine

Experimentalists often use wind tunnels to study aerodynamic turbulence, but most wind tunnel imaging techniques are limited in their ability to take non-invasive 3D density measurements of turbulence. Wavefront tomography is a technique…

Signal Processing · Electrical Eng. & Systems 2026-02-19 Karl J. Weisenburger , Gregery T. Buzzard , Charles A. Bouman , Matthew R. Kemnetz

We propose a UNet-based deep learning model to reconstruct the real-space dark matter (DM) velocity field from the redshift-space distribution of sparse DM halos. Using various statistical measures, we show that the reconstructed velocity…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-26 Xu Xiao , Jiacheng Ding , XiaoLin Luo , Sun Ke Lan , Liang Xiao , Shuai Liu , Xin Wang , Le Zhang , Xiao-Dong Li

Creating 3D maps on robots and other mobile devices has become a reality in recent years. Online 3D reconstruction enables many exciting applications in robotics and AR/VR gaming. However, the reconstructions are noisy and generally…

Computer Vision and Pattern Recognition · Computer Science 2017-03-29 Maksym Dzitsiuk , Jürgen Sturm , Robert Maier , Lingni Ma , Daniel Cremers

Data compression is a method of improving the efficiency of transmission and storage of images. Dithering, as a method of data compression, can be used to convert an 8-bit gray level image into a 1-bit / binary image. Undithering is the…

Computer Vision and Pattern Recognition · Computer Science 2011-08-17 V. Asha

Received signal strength based radio tomographic imaging is a popular device-free indoor localization method which reconstructs the spatial loss field of the environment using measurements from a dense wireless network. Existing methods…

Emerging Technologies · Computer Science 2016-04-12 Hüseyin Yiğitler , Riku Jäntti , Ossi Kaltiokallio , Neal Patwari
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