[B]Interesting Quantum Mechanics Problem[/B]

[teddy]

Suppose we have a particle in a box with infinite potential for x>a and x<0 and zero potential in between.Then by solving the schrd. equation we get a node at x= a/2 for first excited state.Which means the probability of finding the particle at x=a/2 is zero for all times if it is a stationary first excited state.
Then how does the particle travel from one half of the box to the another without encountering the node.I know there is no well defined path but still space is well-connected and have no loops or whatever. I am feeling quite uneasy regarding this.

please....enlightment.

[damgo]

There is no 'travel', just like you said. The particle always has an equal probability of being observed in either half of the box; you can't say it's ever in one or the other, nor that it is traveling between them. I am feeling quite uneasy regarding this. Welcome to the world of QM. [;)] The universe is just really weird; eventually you will get used to it.

[Alexander]

Basicly, this node IS particle itself (along with two maxima). Or consider it to be sum of two "parts" of the particle travelling in opposite directions.

Particles (=waves) are mathematical objects, and their properties do not have to be the same as properties of baseball or ocean wave.