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Schrodinger Equation and the Time-Spent Probability Density Function |
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Let H(p, x) be the Hamiltonian function for a physical system. If H does not explictly
involve time then it is the same as total energy E, kinetic and potential. Then let H^(∇, x) be its
Hamiltonian operator, where momentum p is replaced by ih∇, h
is Planck's constant divided by 2π and i is the square root of negative one.
The time-independent Schrödinger equation for the system is the
For a particle of mass m in a potential field V(x), H^((∇x, x) is of the form
Thus the time-independent Schrödinger equation is
where μ(x)=(2m)/h²
The probability density for a particle at point s of its trajectory when moving at a velocity v is given by
where T is the total time taken to execute the periodi trajectory.
By Hamiltonian analysis the velocity v(x) is given by
For the Hamiltonian function of a particle is a potential field H=p²/2m + V(x)
But for this case
This can be rewritten as
½
In general, velocity may be expressed as a function of kinetic energy K(x)=E−V(x)=E(1−V(x)/E).
Therefore the wavefunction σ(x) associated with the time-spent probability density function PTS(x) is given by
Now let λ(x) be defined by
Now the Schrödinger equation
must be evaluated and that starts with the Laplacian ∇².
The Laplacian is the divergence of the gradient of a scalar field; i.e.,
The Laplacian ∇² of the product of two functions f·g is given by
Again for typographic convenience let J(x)−¼= μE(H(x))−¼ and thus J(x)=(μE)4H(x). Therefore
Therefore
Note that
Since
Therefore
Multiplying through by J¼(z) gives
Note that
and ∇V(z) and ∇²V(z) are fixed as E→∞. Therefore all of the terms on the LHS of the previous equation above except (∇²λ) go to zero as E increases without bound. They approach zero because they have a derivative of J in their numerators involving E³ and a power of J in their denominators involving a power of E4. Furthermore H(z) asymptotically approaches 1 as E→∞. Thus λ(z) asymptotically approaches the solution to the equation
This is a Helmholtz equation. Its solutions in Cartesian coordinate systems are sinusoidal. The values of λ² then oscillate between a maximum value and zero. This function λ(x) could called the flutter function for the system. Its spatial average is a constant. See Helmholtz equation averages.
The fact that the coefficient of the Helmholtz equation is proportional to the fourth power of energy means that as E increases the solution very quickly goes to ultradense fluctuations of probability density such that any degree of spatial averaging results is a close approximation of the Classical time-spent probability density distribution.
So the probability density λ(z)² generally consists of a function which oscillates between relative maxima and zero values. The spatial average of that function is a constant. Therefore the probability densities are inversely proportional to J(x)½=(1-V(x)/E)½ just as the classical time-spent probabilities are.
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