Let P_ab (t) be the probability of finding the particle in the range (a < x < b), at time t.
(a) Show that

What are the units of J (x,t)? J is called the probability current because it tells you the rate at which probability is “flowing” past the point x. If is P_ab (t) is increasing, then more probability is flowing into the region at one end than flows out at the other.

(b) Find the probability current for the wave function in Problem 1.9. (This is not a very pithy example, I’m afraid; we’ll encounter more substantial ones in due course.)

Problem 1.9.

A particle of mass m has the wave function

where A and a are positive real constants.

Transcribed Image Text:

dPab dt = J (a,t) - J (b, 1). where J(x, t) = iħ 24* 4 ( 2m əx 24 əx