2 Slit and Wave Particle

Wave Nature of Light

• In 1803, Thomas Young demonstrated light's wave nature through interference effects.

• The two-slit experiment contradicted Newton's corpuscular theory of light.

Two-Slit Experiment Overview

• Richard Feynman highlights the experiment as central to understanding quantum mechanics' mysteries.

• This phenomenon cannot be explained classically; it reveals quantum characteristics.

Interference Pattern

• Wave crests from two slits act like semicircles of radius $
  $, $2
  $, $3
  $, etc.

• Maxima on the detector occur where the path difference $
  _2 -
  _1 = n
  $ (where $n = 1, 2, 3, …$).

• Intensity on the screen $I(x)$ is due to interference, not just a sum of intensities from individual slits.

Single Photon Experiments

• Experiment 1: A single photon passes through slits; could show spot or dim interference pattern.

• Experiment 2: Repeated trials; possible wave-like pattern or particle-like pattern confirmed.

• Experiment 3: One slit open at a time; particle-like pattern observed.

• Experiment 4: Both slits open with measurement on which slit; still shows particle-like pattern.

Photon Behavior

• Quantum mechanics shows that photons behave both as particles and waves.

• Single photons can exhibit wavelike behavior despite being detected at specific locations.

Notable Quotes

• "The plurality that we perceive is only an appearance; it is not real." - Erwin Schrödinger

• David Bohm emphasizes the need for a non-fragmentary world view in modern physics, suggesting a holistic approach to reality.