473 research outputs found
Nonlinear dynamics of open quantum systems
The evolution of a composite closed system using the integral wave equation
with the kernel in the form of path integral is considered. It is supposed that
a quantum particle is a subsystem of this system. The evolution of the reduced
density matrix of the subsystem is described on the basis of the integral wave
equation for a composite closed system. The equation for the density matrix for
such a system is derived. This equation is nonlinear and depends on the history
of the processes in the closed system. It is shown that, in general, the
reduced density matrix trace does not conserve in the evolution processes
progressing in open systems and the procedure of the trace normalization is
necessary as the mathematical image of a real nonlocal physical process. The
wave function collapse and EPR correlation are described using this approach.Comment: 8
Quantum Particle Motion in Physical Space
Using Feynman's representation of the quantum evolution and considering a
quantum particle as a matter field (continuous medium), it is shown that
individual particles of the field have unique paths of the motion. This allows
describing motion of the quantum particle continuous medium by Lagrange's
method. It is shown that form of the real individual particle path is
determined by classical minimum action principle.Comment: 5 page
Macroscopic Body Motion in Terms of Quantum Evolution
Macroscopic body is considered as a system, consisting of an infinite number
of quantum particles. Mechanical motion of the system center of mass in
physical space is described, using Feynman's representation of the quantum
evolution. It is shown that the center of mass of the system moves accordingly
with the minimum action principle if action functional is much higher then
Plank's constant.Comment: 7
Towards better understanding of the amorphous silica - Alkali reactions and the means of preventing glass aggregate expansion in concrete
The effect of quantity and characteristics of the components of amorphous silica - alkali reactions, based on the research carried at the CSIRO Laboratories in Australia and by the author are discussed. Conditions under which the expansion of silica-gel can be reduced to a safe level or even completely eliminated are presented. The emphasis is made on the commercially viable and the most economical means of the safe use of crushed soda-lime glasses (which account for about ninety percent of all manufactured glasses) as an aggregate in structural, durable and dimensionally stable concretes, in which hydraulic cements are used as a binder. With the depletion of good quality natural aggregates from quarries located in the proximity of construction and development sites, the use of recycled materials becomes particularly important in the current climate of global recession. It should be emphasized, however, that the results of these findings may not be universal, and when applied to the specific local conditions (both - glass and hydraulic cements) should be verified in the laboratory tests
- β¦