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The concordance model of cosmology predicts a universe which finishes in a finite amount of conformal time at a future conformal boundary. We show that for particular cases we study, the background variables and perturbations may be…

General Relativity and Quantum Cosmology · Physics 2022-05-18 A. N. Lasenby , W. J. Handley , D. J. Bartlett , C. S. Negreanu

The nonlinear supersymmetry of one-dimensional systems is investigated in the context of the quantum anomaly problem. Any classical supersymmetric system characterized by the nonlinear in the Hamiltonian superalgebra is symplectomorphic to…

High Energy Physics - Theory · Physics 2009-10-31 Sergey Klishevich , Mikhail Plyushchay

Theories involving localized collapse allow the possibility that classical information could be obtained about quantum states without using POVMS and without allowing superluminal signalling. We can model this by extending quantum theory to…

Quantum Physics · Physics 2021-03-31 Adrian Kent

In this work spontaneous (non-dynamical) breaking (effective hiding) of the unitary quantum mechanical dynamical symmetry (superposition) is considered. It represents an especial but very interesting case of the general formalism of the…

Quantum Physics · Physics 2007-05-23 Vladan Pankovic , Milan Predojevic

Semiclassical states in isotropic loop quantum cosmology are employed to show that the improved dynamics has the correct classical limit. The effective Hamiltonian for the quantum cosmological model with a massless scalar field is thus…

General Relativity and Quantum Cosmology · Physics 2009-02-27 You Ding , Yongge Ma , Jinsong Yang

Unified models incorporating the right handed neutrino in a symmetric way generically possess parity symmetry. If this is broken spontaneously it results in the formation of domain walls in the early Universe, whose persistence is unwanted.…

High Energy Physics - Theory · Physics 2014-02-03 Urjit A. Yajnik , Sasmita Mishra , Debasish Borah

By considering (non-relativistic) quantum mechanics as it is done in practice in particular in condensed-matter physics, it is argued that a deterministic, unitary time evolution within a chosen Hilbert space always has a limited scope,…

Quantum Physics · Physics 2017-10-03 Barbara Drossel

We introduce the set of constraints the wave function of the Universe has to satisfy in order to describe an Universe undergoing through the process of spontaneous breaking of supersymmetry and discuss the way this may lead to the emergence…

General Relativity and Quantum Cosmology · Physics 2007-05-23 O. Bertolami , P. V. Moniz

A cosmology inspired structure for phase space is introduced, which leads to finitization and lattice-like discretization of position and momentum eigenvalues in a preferred, cosmic frame. Lorentz invariance is broken at very high energies,…

High Energy Physics - Theory · Physics 2007-05-23 Helio Fagundes

Many candidate fundamental theories contain scalar fields that can acquire spacetime-varying expectation values in a cosmological context. Such scalars typically obey Lorentz-violating effective dispersion relations. We illustrate this fact…

Astrophysics · Physics 2009-11-10 Orfeu Bertolami , Ralf Lehnert , Robertus Potting , Andre Ribeiro

We study the concepts of compatibility and separability and their implications for quantum and classical systems. These concepts are illustrated on a macroscopic model for the singlet state of a quantum system of two entangled spin 1/2 with…

Quantum Physics · Physics 2012-03-28 Diederik Aerts , Christian de Ronde , Bart D'Hooghe

Light scalar fields very naturally appear in modern cosmological models, affecting such parameters of Standard Model as electromagnetic fine structure constant $\alpha$, dimensionless ratios of electron or quark mass to the QCD scale,…

Atomic Physics · Physics 2009-08-18 V. V. Flambaum , E. V. Shuryak

The main argument by proponents of Many-World interpretations of quantum mechanics is that as more and more previously disentangled degrees of freedom become entangled with the microscopic degree we measure, there is no way of telling when…

Quantum Physics · Physics 2021-12-15 Martin Greiter

This paper furthers existing evidence that quantum computers are capable of computations beyond classical computers. Specifically, we strengthen the collapse of the polynomial hierarchy to the second level if: (i) Quantum computers with…

Quantum Physics · Physics 2024-10-29 Simon C. Marshall , Scott Aaronson , Vedran Dunjko

The good agreement between large-scale observations and the predictions of the now-standard $\Lambda$CDM theory gives us hope that this will become a lasting foundation for cosmology. After briefly reviewing the current status of the key…

Astrophysics · Physics 2011-08-23 Joel R. Primack

The quantum measurement problem, the unresolved conflict between the unitary evolution of the wave function and the postulate of wave function collapse, remains the most profound conceptual challenge in quantum foundations. While…

Quantum Physics · Physics 2025-09-17 Eyad I. B Hamid

Quantum-inspired classical algorithms provide us with a new way to understand the computational power of quantum computers for practically-relevant problems, especially in machine learning. In the past several years, numerous efficient…

Quantum Physics · Physics 2025-01-15 Nikhil S. Mande , Changpeng Shao

We consider a minisuperspace model for a closed universe with small and positive cosmological constant, filled with a massive scalar field conformally coupled to gravity. In the quantum version of this model, the universe may undergo a…

General Relativity and Quantum Cosmology · Physics 2009-11-07 D. Levkov , C. Rebbi , V. A. Rubakov

Recent research has demonstrated that quantum computers can solve certain types of problems substantially faster than the known classical algorithms. These problems include factoring integers and certain physics simulations. Practical…

Quantum Physics · Physics 2009-10-30 Emanuel Knill , Raymond Laflamme , Wojciech H. Zurek

It is well known that a minimal distance emerges in quantum field theories owing to the need to regularize the UV divergences. The macroscopical limit at large minimal distance, weak spatial resolution, is investigated for a self…

High Energy Physics - Theory · Physics 2025-10-22 S. Nagy , J. Polonyi