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tags: #physics #quantum-mechanics #waves

The double-slit experiment is the quintessential demonstration of wave-particle duality and the strangeness of the quantum world.

The Setup:

1. A beam of particles (like electrons or photons) is fired at a barrier with two thin, parallel slits.
2. A detector screen is placed behind the barrier to record where the particles land.

The Results:

• If you fire the particles one at a time without observing which slit they go through, they create an interference pattern on the screen—a series of bright and dark bands. This pattern is a hallmark of waves interfering with each other, implying each particle somehow went through both slits at once.
• If you place a detector at the slits to see which one each particle goes through, the interference pattern vanishes. The particles behave like simple bullets, creating two distinct bands on the screen.

The Implication:
The act of observation forces a quantum system to "choose" a single state, collapsing its wave function. This experiment fundamentally challenges our classical intuition about reality, suggesting that, at a deep level, reality is probabilistic and influenced by measurement. This raises profound questions, echoing the themes in Plato's Allegory of the Cave about the difference between perceived reality and true reality.

Reference

Coursera, "Question Reality: Matter"