Heisenberg's Uncertainty Principle Presentation -1.pptx

Heisenberg's Uncertainty Principle

1. Heisenberg's Uncertainty Principle

2. The Heisenberg uncertainty principle is one of the fundamental principles of quantum mechanics. It states that there is a fundamental limit to the precision with which certain pairs of physical properties, such as position and momentum, can be known simultaneously. In other words, the more accurately you measure one property, the less accurately you can know the other.

3. Propagation of  de Broglie waves  in 1d—real part of the  complex  amplitude is blue, imaginary part is green. The probability (shown as the colour  opacity ) of finding the particle at a given point  x  is spread out like a waveform, there is no definite position of the particle. As the amplitude increases above zero the  curvature  reverses sign, so the amplitude begins to decrease again, and vice versa—the result is an alternating amplitude: a wave.

4. The uncertainty principle can be visualized using the position- and momentum-space wavefunctions for one spinless particle with mass in one dimension. The more localized the position-space wavefunction , the more likely the particle is to be found with the position coordinates in that region, and correspondingly the momentum-space wavefunction is less localized so the possible momentum components the particle could have are more widespread. Conversely, the more localized the momentum-space wavefunction , the more likely the particle is to be found with those values of momentum components in that region, and correspondingly the less localized the position-space wavefunction , so the position coordinates the particle could occupy are more widespread. These wavefunctions are  Fourier transforms  of each other: mathematically, the uncertainty principle expresses the relationship between conjugate variables in the transform.

5. But the snapshot alone would not give us enough information about its speed. Right: As the rollercoaster car descends the hill, we can measure its speed over time but would be less certain about its position. The uncertainty principle is a trade-off between two complementary variables, such as position and speed. The rollercoaster above serves as an analogy for how the uncertainty principle works at scales much smaller than this. Left: When the rollercoaster car reaches the peak of the hill, we could take a snapshot and know its location.

6. The reality we can put into words is never reality itself. An expert is someone who knows some of the worst mistakes that can be made in his subject, and how to avoid them. Not only is the Universe stranger than we think, it is stranger than we can think. What we observe is not nature itself, but nature exposed to our method of questioning.