Quantum Mechanical, Statistical Mechanical and Classical Spatial Probability Distributions
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Description
Quantum mechanical spatial probability densities may be obtained by solving the time independent Schrodinger equation. Statistical mechanical spatial densities may be obtained by maximizing Shannon´s entropy d(r)ln[d(r)] (where d(r) is the spatial density) subject to appropriate constraints. A classical spatial probability density may be obtained from 1/v(x) where v(x) is the velocity at position x obtained from kinetic energy + potential energy (x) =total energy. Recently, there have been attempts to link these various spatial probability densities. For example for the ground state wavefunction of a harmonic oscillator, the Schrodinger equation can be obtained from varying Shannon´s entropy with constraints because V(x) W*(x) W(x) (where W(x) is the wavefunction) can be written in the form of Shannon´s entropy times a constant [3]. Furthermore, Casal et al have maximized Tsalis´ entropy to obtain good approximations to the ground state wavefunctions of oscillators and Coulomb potentials. In [1], the classical density 1/v(x) has been calculated using energy levels from quantum mechanics, namely E=hbar w (n+.5). This density has in turn been used to calculate entropy and compared with results from wavefunctions of the Schrodinger equation with good results even for low n values even though for n=0, the wavefunction W(x)=1/C exp(-ax2) and 1/v(x) are not at all similar. The purpose of this note, is to attempt to examine the relationship between these different spatial densities.