The Experts below are selected from a list of 24 Experts worldwide ranked by ideXlab platform

Carlo Rovelli - One of the best experts on this subject based on the ideXlab platform.

  • Aristotle's Physics: a Physicist's Look
    arXiv: History and Philosophy of Physics, 2013
    Co-Authors: Carlo Rovelli
    Abstract:

    I show that Aristotelian physics is a correct and non-intuitive approximation of Newtonian physics in the suitable domain (motion in fluids), in the same technical sense in which Newton Theory is an approximation of Einstein's Theory. Aristotelian physics lasted long not because it became dogma, but because it is a very good empirically grounded Theory. The observation suggests some general considerations on inter-theoretical relations.

Leonid Fedorov - One of the best experts on this subject based on the ideXlab platform.

  • Linearized Equations of General Relativity and the Problem of Reduction to the Newton Theory
    Journal of Modern Physics, 2020
    Co-Authors: Valery Vasiliev, Leonid Fedorov
    Abstract:

    The paper is concerned with the problem of reduction of the general relativity Theory to the Newton gravitation Theory for a gravitation field with relatively low intensity. This problem is traditionally solved on the basis of linearized equations of general relativity which, being matched to the Newton Theory equations, allow us to link the classical gravitation constant with the constant entering the general relativity equations. Analysis of the linearized general relativity equations shows that it can be done only for empty space in which the energy tensor is zero. In solids, the set of linearized general relativity equations is not consistent and is not reduced to the Newton Theory equations. Specific features of the problem are demonstrated with the spherically symmetric static problem of general relativity which has the closed-form solution.

Valery Vasiliev - One of the best experts on this subject based on the ideXlab platform.

  • Linearized Equations of General Relativity and the Problem of Reduction to the Newton Theory
    Journal of Modern Physics, 2020
    Co-Authors: Valery Vasiliev, Leonid Fedorov
    Abstract:

    The paper is concerned with the problem of reduction of the general relativity Theory to the Newton gravitation Theory for a gravitation field with relatively low intensity. This problem is traditionally solved on the basis of linearized equations of general relativity which, being matched to the Newton Theory equations, allow us to link the classical gravitation constant with the constant entering the general relativity equations. Analysis of the linearized general relativity equations shows that it can be done only for empty space in which the energy tensor is zero. In solids, the set of linearized general relativity equations is not consistent and is not reduced to the Newton Theory equations. Specific features of the problem are demonstrated with the spherically symmetric static problem of general relativity which has the closed-form solution.

Steven A. Gabriel - One of the best experts on this subject based on the ideXlab platform.

  • A Hybrid Smoothing Method for Mixed Nonlinear Complementarity Problems
    Computational Optimization and Applications, 1998
    Co-Authors: Steven A. Gabriel
    Abstract:

    In this paper, we describe a new, integral-based smoothing method for solving the mixed nonlinear complementarity problem (MNCP). This approach is based on recasting MNCP as finding the zero of a nonsmooth system and then generating iterates via two types of smooth approximations to this system. Under weak regularity conditions, we establish that the sequence of iterates converges to a solution if the limit point of this sequence is regular. In addition, we show that the rate is Q-linear, Q-superlinear, or Q-quadratic depending on the level of inexactness in the subproblem calculations and we make use of the inexact Newton Theory of Dembo, Eisenstat, and Steihaug. Lastly, we demonstrate the viability of the proposed method by presenting the results of numerical tests on a variety of complementarity problems.

Qin Zhao - One of the best experts on this subject based on the ideXlab platform.

  • hypersonic limit of two dimensional steady compressible euler flows passing a straight wedge
    arXiv: Analysis of PDEs, 2019
    Co-Authors: Aifang Qu, Hairong Yuan, Qin Zhao
    Abstract:

    We formulated a problem on hypersonic limit of two-dimensional steady non-isentropic compressible Euler flows passing a straight wedge. It turns out that Mach number of the upcoming uniform supersonic flow increases to infinite may be taken as the adiabatic exponent $\gamma$ of the polytropic gas decreases to $1$. We proposed a form of the Euler equations which is valid if the unknowns are measures and constructed a measure solution contains Dirac measures supported on the surface of the wedge. It is proved that as $\gamma \to1$, the sequence of solutions of the compressible Euler equations that containing a shock ahead of the wedge converge vaguely as measures to the measure solution we constructed. This justified the Newton Theory of hypersonic flow passing obstacles in the case of two-dimensional straight wedges. The result also demonstrates the necessity of considering general measure solutions in the studies of boundary-value problems of systems of hyperbolic conservation laws.