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The ``generic'' family of classical sequential growth dynamics for causal sets provides cosmological models of causal sets which are a testing ground for ideas about the, as yet unknown, quantum theory. In particular we can investigate how…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Graham Brightwell , H. Fay Dowker , Raquel S. Garcia , Joe Henson , Rafael D. Sorkin

Classical sequential growth models for causal sets provide an important step towards the formulation of a quantum causal set dynamics. The covariant observables in a class of these models known as generalised percolation have been…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Fay Dowker , Sumati Surya

The spacetime discreteness of causal set theory has enabled the formulation of novel spacetime dynamics. In these so-called "growth" dynamics, a causal set spacetime is generated probabilistically by means of a random walk on certain tree…

General Relativity and Quantum Cosmology · Physics 2023-02-22 Stav Zalel

One of approaches to quantum gravity is different models of a discrete pregeometry. An example of a discrete pregeometry on a microscopic scale is introduced. This is the particular case of a causal set. The causal set is a locally finite…

General Relativity and Quantum Cosmology · Physics 2011-07-01 Alexey L. Krugly

A causal set is a partially ordered set on a countably infinite ground-set such that each element is above finitely many others. A natural extension of a causal set is an enumeration of its elements which respects the order. We bring…

Probability · Mathematics 2011-09-22 Graham Brightwell , Malwina Luczak

Starting from certain causality conditions and a discrete form of general covariance, we derive a very general family of classically stochastic, sequential growth dynamics for causal sets. The resulting theories provide a relatively…

General Relativity and Quantum Cosmology · Physics 2011-05-05 D. P. Rideout , R. D. Sorkin

We point out that a quantum system with a strongly positive quantum measure or decoherence functional gives rise to a vector valued measure whose domain is the algebra of events or physical questions. This gives an immediate handle on the…

General Relativity and Quantum Cosmology · Physics 2010-11-30 Fay Dowker , Steven Johnston , Sumati Surya

We address the extension problem for quantal measures of path-integral type, concentrating on two cases: sequential growth of causal sets, and a particle moving on the finite lattice Z_n. In both cases the dynamics can be coded into a…

High Energy Physics - Theory · Physics 2011-04-11 Rafael D. Sorkin

We explore whether the growth dynamics paradigm of Causal Set Theory is compatible with past-infinite causal sets. We modify the Classical Sequential Growth dynamics of Rideout and Sorkin to accommodate growth "into the past" and discuss…

General Relativity and Quantum Cosmology · Physics 2021-09-23 Bruno Valeixo Bento , Fay Dowker , Stav Zalel

A covariant causal set (c-causet) is a causal set that is invariant under labeling. Such causets are well-behaved and have a rigid geometry that is determined by a sequence of positive integers called the shell sequence. We first consider…

General Relativity and Quantum Cosmology · Physics 2013-11-26 Stan Gudder

A review is given of recent work aimed at constructing a quantum theory of cosmology in which all observables refer to information measurable by observers inside the universe. At the classical level the algebra of observables should be…

High Energy Physics - Theory · Physics 2009-10-31 Fotini Markopoulou

Analyzing the covariance structure of data is a fundamental task of statistics. While this task is simple for low-dimensional observations, it becomes challenging for more intricate objects, such as multivariate functions. Here, the…

Methodology · Statistics 2023-01-12 Holger Dette , Gauthier Dierickx , Tim Kutta

Growth charts are often more informative when they are customized per subject, taking into account prior measurements and possibly other covariates of the subject. We study a global semiparametric quantile regression model that has the…

Statistics Theory · Mathematics 2007-06-13 Ying Wei , Xuming He

Adjusting for covariates is a well established method to estimate the total causal effect of an exposure variable on an outcome of interest. Depending on the causal structure of the mechanism under study there may be different adjustment…

Statistics Theory · Mathematics 2021-04-27 Jack Kuipers , Giusi Moffa

Previously, we showed that computational mechanic's causal states -- predictively-equivalent trajectory classes for a stochastic dynamical system -- can be cast into a reproducing kernel Hilbert space. The result is a widely-applicable…

Machine Learning · Computer Science 2024-10-03 Alexandra M. Jurgens , Nicolas Brodu

A standard assumption for causal inference from observational data is that one has measured a sufficiently rich set of covariates to ensure that within covariate strata, subjects are exchangeable across observed treatment values. Skepticism…

Methodology · Statistics 2020-09-24 Eric J Tchetgen Tchetgen , Andrew Ying , Yifan Cui , Xu Shi , Wang Miao

In causal set theory, cycles of cosmic expansion and collapse are modelled by causal sets with "breaks" and "posts" and a special role is played by cyclic dynamics in which the universe goes through perpetual cycles. We identify and…

General Relativity and Quantum Cosmology · Physics 2023-07-18 Fay Dowker , Stav Zalel

The standard formalism of quantum theory is enhanced and definite meaning is given to the concepts of experiment, measurement and event. Within this approach one obtains a uniquely defined piecewise deterministic algorithm generating…

High Energy Physics - Theory · Physics 2011-08-17 Ph. Blanchard , A. Jadczyk

Causality imposes strong restrictions on the type of operators that may be observables in relativistic quantum theories. In fact, causal violations arise when computing conditional probabilities for certain partial causally connected…

Quantum Physics · Physics 2009-11-07 Rodolfo Gambini , Rafael A. Porto

In ordinary Quantum Mechanics only ideally instantaneous observations of a quantity or a set of compatible quantities are usually considered. In an old paper of our group in Milano a formalism was introduced for the continuous monitoring of…

Quantum Physics · Physics 2015-08-27 G. M. Prosperi
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