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We investigate implications of decoherence for quantum systems which are classically chaotic. We show that, in open systems, the rate of von Neumann entropy production quickly reaches an asymptotic value which is: (i) independent of the…

General Relativity and Quantum Cosmology · Physics 2011-08-04 Wojciech Hubert Zurek , Juan Pablo Paz

KKLT give a mechanism to generate de Sitter vacua in string theory. And recently, the scenario, {\em landscape}, is suggested to explain the problem of the cosmological constant. In this scenario, the cosmological constant is a de Sitter…

High Energy Physics - Theory · Physics 2009-07-06 C. Y. Sun , D. H. Zhang

What can be measured by an observer in our universe? We address this question by constructing an algebra of gravitationally-dressed observables accessible to a comoving observer in FLRW spacetimes that are asymptotically de Sitter in the…

High Energy Physics - Theory · Physics 2024-07-01 Jonah Kudler-Flam , Samuel Leutheusser , Gautam Satishchandran

The fact that we rarely directly observe much quantum uncertainty is often attributed to decoherence. However, decoherence does not reduce the quantum uncertainty in the full quantum state. Whether or not it reduces the quantum…

Quantum Physics · Physics 2021-09-10 Don N. Page

The formalism of quantum theory in Hilbert space has been applied with success to the modeling and explanation of several cognitive phenomena, whereas traditional cognitive approaches were problematical. However, this 'quantum cognition…

Artificial Intelligence · Computer Science 2019-02-12 Diederik Aerts , Lyneth Beltran , Massimiliano Sassoli de Bianchi , Sandro Sozzo , Tomas Veloz

This paper investigates the influence of extra dimensions on the nature of the arrow of time. We demonstrate that the observed arrow of time can be explained by the monotonic growth of the multidimensional manifold's volume. Unlike…

General Relativity and Quantum Cosmology · Physics 2026-02-03 Sergey G. Rubin

We show that the quantum universe emerging from a nonperturbative, Lorentzian sum-over-geometries can be described with high accuracy by a four-dimensional de Sitter spacetime. By a scaling analysis involving Newton's constant, we establish…

High Energy Physics - Theory · Physics 2009-12-15 J. Ambjorn , A. Gorlich , J. Jurkiewicz , R. Loll

We describe progress towards constructing a quantum theory of de Sitter space in four dimensions. In particular we indicate how both particle states and Schwarzschild de Sitter black holes can arise as excitations in a theory of a finite…

High Energy Physics - Theory · Physics 2009-11-11 T. Banks , B. Fiol , A. Morisse

Some form of approximately exponential inflation is generally assumed to be the origin of our present universe. The inflation is thought to be driven by a scalar field potential where the field first slowly slides along the potential and…

General Relativity and Quantum Cosmology · Physics 2023-04-27 Gustaf Rydbeck

We discuss several aspects of quantum field theory of a scalar field in a Friedmann universe, clarifying and highlighting several conceptual and technical issues. (A) We show that one can map the dynamics of (1) a massless scalar field in a…

General Relativity and Quantum Cosmology · Physics 2019-01-17 Kinjalk Lochan , Karthik Rajeev , Amit Vikram , T. Padmanabhan

We establish the linear instability of the semiclassical Einstein-Klein-Gordon system linearised about the Minkowski vacuum spacetime. The proof relies on formulating a forcing problem for both metric and state perturbations within the…

Mathematical Physics · Physics 2026-04-02 Stefano Galanda , Paolo Meda , Simone Murro , Nicola Pinamonti , Gabriel Schmid

We analyze the renormalization properties of quantum field theories in de Sitter space and show that only two of the maximally invariant vacuum states of free fields lead to consistent perturbation expansions. One is the Euclidean vacuum,…

High Energy Physics - Theory · Physics 2009-11-07 T. Banks , L. Mannelli

The effect of the spontaneous nucleation of black holes in de Sitter space is reviewed, and the main steps of the calculation in Nucl.Phys. B 582, 313, 2000 of the one-loop amplitude of this process are summarized. The existence of such an…

High Energy Physics - Theory · Physics 2007-05-23 Mikhail S. Volkov

Subjective expected utility theory assumes that decision-makers possess unlimited computational resources to reason about their choices; however, virtually all decisions in everyday life are made under resource constraints - i.e.…

Machine Learning · Statistics 2016-10-07 Pedro A. Ortega , Alan A. Stocker

We consider scalar field theory in de Sitter space with a general vacuum invariant under the continuously connected symmetries of the de Sitter group. We begin by reviewing approaches to define this as a perturbative quantum field theory.…

High Energy Physics - Theory · Physics 2009-11-10 Kevin Goldstein , David A. Lowe

This work is concerned with the generation of decay estimates in the velocity variable for solutions of the space-inhomogeneous Boltzmann equation without cutoff on a bounded spatial domain for hard and moderately soft potentials. We work…

Analysis of PDEs · Mathematics 2026-04-28 Cyril Imbert , Amélie Loher

Contrary to common belief, it is not difficult to construct deterministic models where stochastic behavior is correctly described by quantum mechanical amplitudes, in precise accordance with the Copenhagen-Bohr-Bohm doctrine. What is…

Quantum Physics · Physics 2007-05-23 Gerard 't Hooft

The recent controversy of applicability of quantum formalism to brain dynamics has been critically analysed. The prerequisites for any type of quantum formalism or quantum field theory is to investigate whether the anatomical structure of…

Quantum Physics · Physics 2007-05-23 Sisir Roy , Menas Kafatos

A realist description of our universe requires a twofold concept of locality. On one hand, there are the strictly Einstein-local interactions which generate the time evolution. On the other hand, the quantum state space calls for a…

Quantum Physics · Physics 2013-08-27 Andreas O. Tell

We consider the quantum description of a toy model universe in which the Schwarzschild-de Sitter geometry emerges from the coherent state of a massless scalar field. Although highly idealised, this simple model allows us to find clear hints…

General Relativity and Quantum Cosmology · Physics 2022-01-19 Andrea Giusti , Silvia Buffa , Lavinia Heisenberg , Roberto Casadio