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Zhaoyan Wu

Publications and source records attributed to Zhaoyan Wu.

6 recordsLinked to original sources
arXiv2013

Pseudotensor problem of gravitational energy-momentum and Noether's theorem revisited

Based on a general variational principle, Noether's theorem is revisited. It is shown that the so called pseudotensor problem of the gravitational energy-momentum is a result of mis-reading Noether's theorem, and in fact, all the Noether's conserved quantities are scalars. It is also shown, by using a counter-example, that the non-localizability of gravitational energy-momentum can not be attributed to the equivalence principle. As a direct consequence of variational principle, a generalized Hamilton-Jacobi equation for the Hamilton's principal functional is obtained.

gr-qc↗
arXiv2012

Synchronization of an evolving complex hyper-network

In this paper, the synchronization in a hyper-network of coupled dynamical systems is investigated for the first time. An evolving hyper-network model is proposed for better describing some complex systems. A concept of joint degree is introduced, and the evolving mechanism of hyper-network is given with respect to the joint degree. The hyper-degree distribution of the proposed evolving hyper-network is derived based on a rate equation method and obeys a power law distribution. Furthermore, the synchronization in a hyper-network of coupled dynamical systems is investigated for the first time. By calculating the joint degree matrix, several simple yet useful synchronization criteria are obtained and illustrated by several numerical examples.

nlin.AO↗
arXiv2008

A General Variational Principle of Classical Field and Its Application to General relativity I

A general variational principle of classical fields with a Lagrangian containing the field quantity and its derivatives of up to the N-th order is presented. Noether's theorem is derived. The generalized Hamilton-Jacobi's equation for the Hamilton's principal functional is obtained. These results are surprisingly in great harmony with each other. They will be applied to the general relativity in the subsequent articles, especially the generalized Noether's theorem will be applied to the problem of conservation and non-conservation in curved spacetime..

physics.gen-ph↗
arXiv2007

No-Go Theorem for Energy-Momentum Conservation in Curved Spacetime

It is pointed out that in curved spacetime, one cannot define the sum of energy-momemtum 4-vector over a space-like hypersurface. The difficulty in finding satisfactory gravitational energy-momentum complex stems from misunderstanding of this question. The law of conservation of energy-momentum holds valid only approximately when spacetime is not seriously curved.

gr-qc↗
arXiv2004

Validity of Quantum Adiabatic Theorem

The consistency of quantum adiabatic theorem has been doubted recently. It is shown in the present paper that the difference between the adiabatic solution and the exact solution to the Schrodinger equation with a slowly changing driving Hamiltonian is small; while the difference between their time derivatives is not small. This explains why substituting the adiabatic solution back into Schrodinger equation leads to "inconsisitency" of the adiabatic theorem. Physics is determined completely by the state vector, and not by its time drivative. Therefore the quantum adiabatic theorem is physically correct.

quant-ph↗