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Quantum mechanical unitarity in our universe is challenged both by the notion of the big bang, in which nothing transforms into something, and the expansion of space, in which something transforms into more something. This motivates the…

High Energy Physics - Theory · Physics 2022-02-08 Jordan Cotler , Andrew Strominger

We consider a problem of the consistent deformation of physical system introducing a new features, but preserving its fundamental properties. In particular, we study how to implement the noncommutativity of space-time without violation of…

High Energy Physics - Theory · Physics 2014-09-15 V. G. Kupriyanov

The relativistic theory of unconstrained $p$-dimensional membranes ($p$-branes) is further developed and then applied to the embedding model of induced gravity. Space-time is considered as a 4-dimensional unconstrained membrane evolving in…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Matej Pavsic

For some time the York time parameter has been identified as a candidate for a physically meaningful time in cosmology. An associated Hamiltonian may be found by solving the Hamiltonian constraint for the momentum conjugate to the York time…

General Relativity and Quantum Cosmology · Physics 2016-03-23 Philipp Roser

A discussion is given of the quantisation of a physical system with finite degrees of freedom subject to a Hamiltonian constraint by treating time as a constrained classical variable interacting with an unconstrained quantum state. This…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Charles Wang

The real- and imaginary-time evolution of quantum states are powerful tools in physics, chemistry, and beyond, to investigate quantum dynamics, prepare ground states or calculate thermodynamic observables. On near-term devices, variational…

Quantum Physics · Physics 2024-02-27 Julien Gacon , Jannes Nys , Riccardo Rossi , Stefan Woerner , Giuseppe Carleo

The theoretical framework established in arXiv:quant-ph/0404103 is extended to deal with possible astrophysical manifestations of phenomena involving reverse, as well as forward, causation in time. The basic idea is that space-time…

General Relativity and Quantum Cosmology · Physics 2009-11-11 G. E. Hahne

We propose a stochastic interpretation of spacetime non-commutativity starting from the path integral formulation of quantum mechanical commutation relations. We discuss how the (non-)commutativity of spacetime is inherently related to the…

High Energy Physics - Theory · Physics 2025-03-12 Michele Arzano , Folkert Kuipers

The treatment of time in relativity does not conform to that in quantum theory. To resolve the discrepancy, a formalization of time is introduced in an accompanying paper, starting from the assumption that the treatment of time in physics…

Quantum Physics · Physics 2024-11-06 Per Östborn

Based on the observation that the exterior space-times of Schwarzschild-type solutions allow two symmetric slicings, a static spherically symmetric one and a timelike homogeneous one, modifications of gravitational dynamics suggested by…

General Relativity and Quantum Cosmology · Physics 2020-08-11 Martin Bojowald

The evolution equations of quantum observables are derived from the classical Hamiltonian equations of motion with the only additional assumption that the phase space is non-commutative. The demonstration of the quantum evolution laws is…

Quantum Physics · Physics 2007-05-23 Daniela Dragoman

We present exact quantum solutions for a noncommutative, multidimensional cosmological model and show that stabilization of extra dimensions sets in with the introduction of noncommutativity between the scale factors. An interpretation is…

General Relativity and Quantum Cosmology · Physics 2008-11-26 N. Khosravi , S. Jalalzadeh , H. R. Sepangi

In general-covariant theories the Hamiltonian is a constraint, and hence there is no time evolution; this is the problem of time. In the subcritical free string, the Hamiltonian ceases to be a constraint after quantization due to conformal…

High Energy Physics - Theory · Physics 2007-05-23 T. A. Larsson

The rules of quantum mechanics require a time coordinate for their formulation. However, a notion of time is in general possible only when a classical spacetime geometry exists. Such a geometry is itself produced by classical matter…

Quantum Physics · Physics 2007-05-23 T. P. Singh

The nonadiabatic geometric phase in a time dependent quantum evolution is shown to provide an intrinsic concept of time having dual properties relative to the external time. A nontrivial extension of the ordinary quantum mechanics is thus…

High Energy Physics - Theory · Physics 2007-05-23 Dhurjati Prasad Datta

We introduce a new set of noncommutative space-time commutation relations in two space dimensions. The space-space commutation relations are deformations of the standard flat noncommutative space-time relations taken here to have position…

High Energy Physics - Theory · Physics 2015-03-13 Andreas Fring , Laure Gouba , Frederik G. Scholtz

Loop Quantum Gravity faces challenges in constructing a well-defined Hamiltonian constraint and understanding the quantum notion of time. In this paper these issues are studied by quantizing the $U(1)^3$ model, a simplified system…

General Relativity and Quantum Cosmology · Physics 2024-12-02 Sepideh Bakhoda , Yongge Ma

In a recent paper we have suggested that a formulation of quantum mechanics should exist, which does not require the concept of time, and that the appropriate mathematical language for such a formulation is noncommutative differential…

General Relativity and Quantum Cosmology · Physics 2015-06-25 T. P. Singh

The time evolution problem for non-self adjoint second order differential operators is studied by means of the path integral formulation. Explicit computation of the path integral via the use of certain underlying stochastic differential…

Mathematical Physics · Physics 2021-07-20 Anastasia Doikou , Simon J. A. Malham , Anke Wiese

Collapse models possibly suggest the need for a better understanding of the structure of space-time. We argue that physical space, and space-time, are emergent features of the Universe, which arise as a result of dynamical collapse of the…

Quantum Physics · Physics 2017-02-01 Tejinder P. Singh