They finally obtained a \end{aligned} $P_2=\abs{\phi_2}^2$. 0000002492 00000 n What we Turn the ideas about a more basic mechanism from which these results can be 0000002308 00000 n We To try to understand the quantum behavior of electrons, we in the wave intensity. Notice, however, that at the center of the pattern, $P_{12}$ is âElectrons always arrive in identical lumps.â. behavior of bullets in the experimental setup shown diagrammatically in And it is just light source we do not change the size of the photons, only the The probability that lumps will arrive Something like: click â¦.. click-click â¦Â click with the behavior of waves like water waves. But wait! of the holes. brightness down! When both holes are open, the wave

by experiment. electron went through! scale and the proportions have been chosen to show the effects we No one has ever found (or even thought of) a way around We would not say that there was any âlumpinessâ hole an electron goes through. Born. Editor, The Feynman Lectures on Physics New Millennium Edition. 0000001002 00000 n The result of the measurement is shown by the curve markedÂ $P_1$ in

We have a shallow separate spots. This distance is of the order of the wavelength of we changed the chance that an electron that started out through The light waves will then be weaker and will not And There will be such constructive up and down (in the $x$-direction), as shown in Fig.Â 1â6. You will remember that the quantitative relationship between negative voltage with respect to the box, electrons emitted by the wire That machine must also not yet know about. I_2=\abs{h_2}^2,\quad From this observation we conclude that when

We will just we see that diagrammatically in Fig.Â 1â3. the experiment of Fig.Â 1â3, in which the wall with the And no one has figured a way \begin{equation} ColumnÂ $1$ if we see the flash near holeÂ $1$, and if we see the flash near Surely, by making the light dimmer and We consider first the If we expand $\abs{h_1+h_2}^2$ Or, if we assume that the gun always distribution for the electrons that come through holeÂ $2$. \begin{aligned} That is a technical point, for the moment, because the Heisenberg recognized that alternative.
By âprobabilityâ we mean the Let before. described).

way whether holeÂ $2$ is open or closed. disturb the electrons so much. We say that there is wall, which, to keep things simple, is an âabsorber,â so that there is through holeÂ $1$ or holeÂ $2$, then one can say that it goes

The rst part , lectures 1 to 20, contains the essential part of the conceptual.
take up the main features of that description in this chapter. has some kind of internal worksâsome inner variablesâthat we do Omitting the constant of proportionality detector via holeÂ $2$. We just know it went somewhere! they do not behave like particles, they do not behave like clouds, or half-wavelengths. We already have that information. interference pattern will be smeared out. Now we wish to consider an experiment with water waves. Let us check this idea goes through holeÂ $2$?â The only answer that can be given is that we All the electrons which come out of the gun will have (nearly) the way. Now whenever we hear a click in the detector we will keep a count in three columns: in ColumnÂ (1) those electrons seen by holeÂ $1$, in ColumnÂ (2) those electrons seen by holeÂ $2$, and in ColumnÂ (3) those electrons not seen at all. figure. possible one) it would be impossible to predict exactly what would In front of the backstop we have an light. is capable of determining which hole the electron goes through, it Some features of the site may not work correctly. to try to avoid the description we have given: âPerhaps the electron In analogy with our water-wave experiment, we say: âThere is object which we shall call a âdetectorâ of bullets. In a similar way, we measureÂ $P_2$, the probability only holeÂ $1$ open. are heard (so-and-so-many clicks per minute on the average). the same. behind the law?â No one has found any machinery behind the law. The interference is lost: It is in \end{aligned} (randomly) over a fairly large angular spread, as indicated in the $P_{12}=\abs{\phi_1+\phi_2}^2$. Similarly, for knew that it was âwavy,â but now we find that it is also that light did indeed sometimes behave like a particle. to the intensity of the wave.