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It is now well-understood that a Lorentz boost of a spatially coherent monochromatic optical beam yields a so-called space-time wave packet (STWP): a propagation-invariant pulsed beam whose group velocity is determined by the relative…

Optics · Physics 2023-08-16 Murat Yessenov , Miguel Romer , Naoki Ichiji , Ayman F. Abouraddy

We present numerical relativity simulations of cosmological scenarios in which the universe is smoothed and flattened by undergoing a phase of slow contraction and test their sensitivity to a wide range of initial conditions. Our numerical…

General Relativity and Quantum Cosmology · Physics 2020-08-14 Anna Ijjas , William G. Cook , Frans Pretorius , Paul J. Steinhardt , Elliot Y. Davies

We discuss a model which gives rise to cosmic self-acceleration due to modified gravity. Improvements introduced by this approach are the following: In the coordinate system commonly used, the metric does not grow in the bulk, and no…

High Energy Physics - Theory · Physics 2007-05-23 Gregory Gabadadze

The goal of object detection is to find objects in an image. An object detector accepts an image and produces a list of locations as $(x,y)$ pairs. Here we introduce a new concept: {\bf location-based boosting}. Location-based boosting…

Computer Vision and Pattern Recognition · Computer Science 2013-09-05 Damian Eads , David Helmbold , Ed Rosten

This paper presents two variations of a novel stochastic prediction algorithm that enables mobile robots to accurately and robustly predict the future state of complex dynamic scenes. The proposed algorithm uses a variational autoencoder to…

Robotics · Computer Science 2023-10-17 Zhanteng Xie , Philip Dames

As an alternative to the paradigm of slow roll inflation, we propose an extended scenario of the matter bounce cosmology in which the Universe has experienced a quasi-matter contracting phase with a variable background equation of state…

General Relativity and Quantum Cosmology · Physics 2015-09-04 Jaume de Haro , Yi-Fu Cai

Within the effective field theory approach to cosmic acceleration, the background expansion can be specified separately from the gravitational modifications. We explore the impact of modified gravity in a background different from a…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-15 Guilherme Brando , Felipe T. Falciano , Eric V. Linder , Hermano E. S. Velten

Prediction models are typically optimized independently from decision optimization. A smart predict then optimize (SPO) framework optimizes prediction models to minimize downstream decision regret. In this paper we present dboost, the first…

Machine Learning · Computer Science 2023-06-08 Andrew Butler , Roy H. Kwon

Reconstructing continuous physical fields from sparse measurements is a central inverse problem, but data-driven generative models can produce states that violate governing dynamics. We introduce a physics-informed generative solver that…

Machine Learning · Computer Science 2026-05-22 Ziyuan Zhu , Keyu Hu , Zhifei Chen , Yuhao Shi , Ming Bao , Jing Zhao , Gang Wang , Haitan Xu , Jiadong Li , Qijun Zhao , Xiaodong Li , Minghui Lu , Yanfeng Chen

Recent advances in the literature have demonstrated that standard supervised learning algorithms are ill-suited for problems with endogenous explanatory variables. To correct for the endogeneity bias, many variants of nonparameteric…

Econometrics · Economics 2021-01-18 Edvard Bakhitov , Amandeep Singh

Conditional gradients constitute a class of projection-free first-order algorithms for smooth convex optimization. As such, they are frequently used in solving smooth convex optimization problems over polytopes, for which the computational…

Optimization and Control · Mathematics 2019-10-14 Jelena Diakonikolas , Alejandro Carderera , Sebastian Pokutta

Next-generation galaxy surveys promise unprecedented precision in testing gravity at cosmological scales. However, realising this potential requires accurately modelling the non-linear cosmic web. We address this challenge by exploring…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-20 Julieth Katherine Riveros , Paola Saavedra , Hector J. Hortua , Jorge Enrique Garcia-Farieta , Ivan Olier

We develop an action principle to construct the dynamics that give rise to a minimal generalization of Einstein's equations, where the speed of light ($c$), the gravitational constant ($G$) and the cosmological constant ($\Lambda$) are…

General Relativity and Quantum Cosmology · Physics 2019-06-12 Renato Costa , Rodrigo R. Cuzinatto , Elisa. M. G. Ferreira , Guilherme Franzmann

Continuous state spaces and stochastic, switching dynamics characterize a number of rich, realworld domains, such as robot navigation across varying terrain. We describe a reinforcementlearning algorithm for learning in these domains and…

Machine Learning · Computer Science 2012-06-18 Emma Brunskill , Bethany Leffler , Lihong Li , Michael L. Littman , Nicholas Roy

We present Natural Gradient Boosting (NGBoost), an algorithm for generic probabilistic prediction via gradient boosting. Typical regression models return a point estimate, conditional on covariates, but probabilistic regression models…

Machine Learning · Computer Science 2020-06-11 Tony Duan , Anand Avati , Daisy Yi Ding , Khanh K. Thai , Sanjay Basu , Andrew Y. Ng , Alejandro Schuler

Gradient boosting is a state-of-the-art prediction technique that sequentially produces a model in the form of linear combinations of simple predictors---typically decision trees---by solving an infinite-dimensional convex optimization…

Statistics Theory · Mathematics 2017-07-18 Gérard Biau , Benoît Cadre

Boosting is a popular way to derive powerful learners from simpler hypothesis classes. Following previous work (Mason et al., 1999; Friedman, 2000) on general boosting frameworks, we analyze gradient-based descent algorithms for boosting…

Machine Learning · Computer Science 2012-02-15 Alexander Grubb , J. Andrew Bagnell

We propose a new way of quick and very efficient acceleration of protons and/or electrons in relativistic bulk flows. The new mechanism takes advantage of conversion of particles from the charged state (protons or electrons/positrons) into…

Astrophysics · Physics 2009-11-07 E. V. Derishev , F. A. Aharonian , V. V. Kocharovsky , Vl. V. Kocharovsky

We propose a new probabilistic framework that allows mobile robots to autonomously learn deep, generative models of their environments that span multiple levels of abstraction. Unlike traditional approaches that combine engineered models…

Robotics · Computer Science 2018-01-01 Andrzej Pronobis , Rajesh P. N. Rao

The mobility patterns of people in cities evolve alongside changes in land use and population. This makes it crucial for urban planners to simulate and analyze human mobility patterns for purposes such as transportation optimization and…

Machine Learning · Computer Science 2025-07-17 Seanglidet Yean , Jiazu Zhou , Bu-Sung Lee , Markus Schläpfer