Visualizing causal effects in 4D space-time vector fields

Author(s):  
D. Silver ◽  
M. Gao ◽  
N. Zabusky
Author(s):  
Ioannis T. Georgiou

Presented are interesting results concerning aspects of the space-time characteristics of coherence patterns of ensembles of impulsive coupled acceleration signals developed in the complex domain of a physical multi-body flexible structure. A modal hammer is used to systematically pulse-interrogate the structure whereas a state of the art piezoelectric tri-axial accelerometer is used to collect at a point time series samples of coupled dynamics. We find the remarkable fact that collocated ensembles of signals of the acceleration vector field are underlain by strong spatio-temporal coherence which is robust under random experimental error introduced in the impulsive force protocol of interrogation. Coherence is characterized-identified optimally in terms of Proper Orthogonal Decomposition (POD) modes. The POD-identified space-time coherence structures, or patterns, feature an unparalleled classical modal-like characterization of coherence of collocated multi-dimensional information. The identified dominant POD spatio-temporal patterns have the space-time modulation characteristics of classical normal modes of vibration of three-dimensional coupled structural dynamics. Exploiting in full the transient dynamics and being model free, this test and evaluation modal-like identification technique can lead to a reliable certification procedure of multi-body flexible structural systems in critical applications.


2019 ◽  
Author(s):  
Vitaly Kuyukov

The main problem of the theory of the emergence of space-time is that how to restore the Minkowsky geometry from the original quantum structures. In this paper, we consider the reverse reaction, obtaining space-time from quantum vector fields, similarly to the electric and magnetic fields in the Maxwell equation. In addition, time itself is split into components in three-dimensional space in the form of an inductive quantum field.


2009 ◽  
Vol 85 (99) ◽  
pp. 111-118 ◽  
Author(s):  
Kazim İlarslan ◽  
Emilija Nesovic

We define normal curves in Minkowski space-time E41. In particular, we characterize the spacelike normal curves in E41 whose Frenet frame contains only non-null vector fields, as well as the timelike normal curves in E41 , in terms of their curvature functions. Moreover, we obtain an explicit equation of such normal curves with constant curvatures.


2016 ◽  
Vol 94 (11) ◽  
pp. 1148-1152
Author(s):  
Ragab M. Gad ◽  
A.E. Al Mazrooei

This paper investigates axially symmetric space–times that admit a homothetic vector field based on Lyra’s geometry. The cases when the displacement vector is a function of t and when it is constant are studied. In the context of this geometry, we find and classify the solutions of the Einstein’s field equations for the space–time under consideration, which display a homothetic symmetry.


2005 ◽  
Vol 14 (08) ◽  
pp. 1451-1463 ◽  
Author(s):  
GHULAM SHABBIR ◽  
M. AMER QURESHI

A study of proper projective symmetry in spherically symmetric static space–times is given by using algebraic and direct integration techniques. It is shown that a special class of the above space–time admits proper projective vector fields.


2020 ◽  
Vol 35 (37) ◽  
pp. 2050305
Author(s):  
P. K. Petrov

A simple way to construct models with early cosmological Genesis epoch is to employ bosonic fields whose Lagrangians transform homogeneously under scaling transformation. We show that in these theories, for a range of parameters defining the Lagrangian, there exists a homogeneous power-law solution in flat space-time, whose energy density vanishes, while pressure is negative (power-law Genesis). We find the condition for the legitimacy of the classical field theory description of such a situation. We note that this condition does not hold for our earlier Genesis model with vector field. We construct another model with vector field and power-law background solution in flat space-time, which is legitimately treated within classical field theory, violates the Null Energy Condition (NEC) and is stable. Upon turning on gravity, this model describes the early Genesis stage.


2020 ◽  
Vol 22 (4) ◽  
pp. 223-226
Author(s):  
M.M. Khashaev

Four parameter group of transformations containing rotations and time translations is consi[1]dered due to spherical symmetry and stationarity of the space-time metric. It is found that there exists such a quartet of Killing vector fields which constitute the Lie algebra of the transforma[1]tion group and in which space-like vectors are not orthogonal to the time-like one. The metric corresponding to the Lie algebra of Killing vectors is composed. It is shown that the metric is non-static.


2000 ◽  
Vol 15 (27) ◽  
pp. 1697-1701
Author(s):  
A. B. PESTOV

The Weyl spinor field is a spinor representation of the Weyl non-Abelian gauge group and a source of the Weyl non-Abelian gauge field first originated in 1921. The equation is derived for the Weyl spinor field on the Weitzenböck space–time that has a quadruplet of parallel vector fields as the fundamental structure. The connection between the Weyl non-Abelian gauge theory and the Weitzenböck space–time is established in the form of a consistent system of equations for the Weyl spinor field and the quadruplet of parallel vector fields.


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