Quantum Mechanics Chapter 9 Great Idea: At the subatomic scale, everything is quantized. Any...
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Transcript of Quantum Mechanics Chapter 9 Great Idea: At the subatomic scale, everything is quantized. Any...
![Page 1: Quantum Mechanics Chapter 9 Great Idea: At the subatomic scale, everything is quantized. Any measurement at that scale significantly alters the object.](https://reader036.fdocuments.in/reader036/viewer/2022070411/56649f515503460f94c75044/html5/thumbnails/1.jpg)
Quantum Mechanics
Chapter 9
Great Idea:At the subatomic scale, everything is quantized.
Any measurement at that scale significantly alters the object being measured
![Page 2: Quantum Mechanics Chapter 9 Great Idea: At the subatomic scale, everything is quantized. Any measurement at that scale significantly alters the object.](https://reader036.fdocuments.in/reader036/viewer/2022070411/56649f515503460f94c75044/html5/thumbnails/2.jpg)
Chapter Outline
• The World of the Very Small• Probabilities• Wave-Particle Duality• Wave-Particle Duality and the Bohr
Atom
![Page 3: Quantum Mechanics Chapter 9 Great Idea: At the subatomic scale, everything is quantized. Any measurement at that scale significantly alters the object.](https://reader036.fdocuments.in/reader036/viewer/2022070411/56649f515503460f94c75044/html5/thumbnails/3.jpg)
The World of the Very Small
![Page 4: Quantum Mechanics Chapter 9 Great Idea: At the subatomic scale, everything is quantized. Any measurement at that scale significantly alters the object.](https://reader036.fdocuments.in/reader036/viewer/2022070411/56649f515503460f94c75044/html5/thumbnails/4.jpg)
The World of the Very Small
• Quantum mechanics– Motion of quanta
• Bundles vs. continuous• Does not match our intuition
![Page 5: Quantum Mechanics Chapter 9 Great Idea: At the subatomic scale, everything is quantized. Any measurement at that scale significantly alters the object.](https://reader036.fdocuments.in/reader036/viewer/2022070411/56649f515503460f94c75044/html5/thumbnails/5.jpg)
Measurement & Observation in the Quantum World
• 3 components to measurement– Sample– Source of energy– Detector
• Quantum World– Measurement
alters object
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The Heisenberg Uncertainty Principle
• Uncertainty Principle:– At quantum scale, measurement alters object
• Cannot know position and velocity• Equation:
• Compare large vs. small objects– Small uncertainty with large object– Large uncertainty with small object
m
hvx >ΔΔ *
![Page 7: Quantum Mechanics Chapter 9 Great Idea: At the subatomic scale, everything is quantized. Any measurement at that scale significantly alters the object.](https://reader036.fdocuments.in/reader036/viewer/2022070411/56649f515503460f94c75044/html5/thumbnails/7.jpg)
Probabilities
![Page 8: Quantum Mechanics Chapter 9 Great Idea: At the subatomic scale, everything is quantized. Any measurement at that scale significantly alters the object.](https://reader036.fdocuments.in/reader036/viewer/2022070411/56649f515503460f94c75044/html5/thumbnails/8.jpg)
Probabilities
• Newtonian View– Determine
velocity and position
• Quantum View– Cannot determine
velocity and position
– Use probability
![Page 9: Quantum Mechanics Chapter 9 Great Idea: At the subatomic scale, everything is quantized. Any measurement at that scale significantly alters the object.](https://reader036.fdocuments.in/reader036/viewer/2022070411/56649f515503460f94c75044/html5/thumbnails/9.jpg)
Wave Particle Duality
![Page 10: Quantum Mechanics Chapter 9 Great Idea: At the subatomic scale, everything is quantized. Any measurement at that scale significantly alters the object.](https://reader036.fdocuments.in/reader036/viewer/2022070411/56649f515503460f94c75044/html5/thumbnails/10.jpg)
The Double-Slit Test
• Energy– Particles– Waves
• Photons– Emit photon– Flood of photons
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Double-Slit cont.
• Single photon over time
• Results depend on experimental design
• Visualizing– Not wave or
particle
![Page 12: Quantum Mechanics Chapter 9 Great Idea: At the subatomic scale, everything is quantized. Any measurement at that scale significantly alters the object.](https://reader036.fdocuments.in/reader036/viewer/2022070411/56649f515503460f94c75044/html5/thumbnails/12.jpg)
Wave-Particle Duality and the Bohr Atom
![Page 13: Quantum Mechanics Chapter 9 Great Idea: At the subatomic scale, everything is quantized. Any measurement at that scale significantly alters the object.](https://reader036.fdocuments.in/reader036/viewer/2022070411/56649f515503460f94c75044/html5/thumbnails/13.jpg)
Wave-Particle Duality & the Bohr Atom
• Speed & Wavelength– Faster speed=shorter wavelength
• Particle– Precise velocity=stable orbit
• Wave– Uniform vibration at certain frequencies
• Combine wave & particle?– Only orbits allowed are those where both particle and
wave work
Wave length determines frequency
Bending wave into circular orbit, fit only certain standing waves into orbit
![Page 14: Quantum Mechanics Chapter 9 Great Idea: At the subatomic scale, everything is quantized. Any measurement at that scale significantly alters the object.](https://reader036.fdocuments.in/reader036/viewer/2022070411/56649f515503460f94c75044/html5/thumbnails/14.jpg)
Quantum Weirdness
• Richard Feynmann- “I can safely say that nobody understands quantum mechanics. …Do not keep saying to yourself, ‘But how can it be like that?’… Nobody knows how it can be like that.”
• Be Careful!– Quantum mechanics is still a marvelous
and necessary tool for understanding the quantum world
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Quantum Entanglement
• Quantum Entanglement– Dice
• Photons emitted at same time– Despite distance, remain entangled
• Quantum teleportation