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1. Quantum Debates Shih-Hung Kao Quantum Information and Network Security Lab Information Security Fall 2012 Professor Tzonelih Hwang 1
2. Outline • Light • Black-body Radiation • Double-slit experiment • Timeline • Uncertainty Principle • Bohr-Einstein Debates • EPR Paradox 2
3. Light • Wave • What’s the medium of light “wave”? • Particle - Newton 3
4. Black-body Radiation • Black body, an opaque and non-reflective body. • Radiation has a specific spectrum and intensity that depends only on the temperature. Radiation non-reflective 4
5. Ultraviolet Catastrophe • Rayleigh–Jeans law • Intensity would be infinite if wavelength is close to zero. • 1900 Planck fixed this problem. • “Energy states of a physical system can be discrete.” • 1905 Einstein used quantum hypothesis to explain the photoelectric effect. X-ray, Ultraviolet, ... 5
6. Light • Wave • What’s the media of light “wave”? • Particle - Newton • Wave-particle duality - Einstein 6
7. Yang’s Double-slit experiment • Light owns the property of wave. • Tomas Yang, 1801 Particle Wave 7
8. If the light particle is sent one by one. If we can observe which slit the particle went through 8
9. Timeline • 1900 Planck's constant • 1905 Einstein used quantum hypothesis to explain the photoelectric effect. • 1910 Planck accept quantum hypothesis. • 1913 Bohr model of atom • 1925 Heisenberg’s matrix mechanics • 1926 Schrödinger equation • 1927 Heisenberg’s uncertainty principle 9
10. Uncertainty Principle ? ? observe (measure) or ??? 10
11. Bohr-Einstein Debates • Einstein, Schrödinger : Outer World (or hidden variable) already determine it. • "I like to think that the moon is there even if I am not looking at it.", "My God does not play with dice" • Schrödinger’s Cat • Heisenberg, Bohr: Quantum Mechanism 11
12. 1935 EPR Paradox • Einstein-Podolsky-Rosen 12
13. And then... • 1964 Bell’s Theorem • Now: • Quantum bit • Quantum Computation • Quantum Communication ... etc. 13
14. References - [Introduction to quantum mechanics]( http:// en.wikipedia.org/wiki/ Introduction_to_quantum_mechanics ) - [波爾-愛因斯坦論戰]( http://en.wikipedia.org/wiki/ Bohr–Einstein_debates ) - [與光⼦子玩捉迷藏]( http://phy.ntnu.edu.tw/~changmc/ Article/photon.pdf ), 張明哲, 科學⼈人雜誌 2007 年 6 月號 - [沒有⼈人看月亮時她是否還在那兒?]( http:// www.sciscape.org/articles/epr/index.html ), ⿈黃志偉, SciScape 14