Book contents
- Frontmatter
- Contents
- Preface
- 1 Introduction
- 2 Historical milestones
- 3 Basics of the classical description of light
- 4 Quantum mechanical understanding of light
- 5 Light detectors
- 6 Spontaneous emission
- 7 Interference
- 8 Photon statistics
- 9 Squeezed light
- 10 Measuring distribution functions
- 11 Optical Einstein–Podolsky–Rosen experiments
- 12 Quantum cryptography
- 13 Quantum teleportation
- 14 Summarizing what we know about the photon
- 15 Appendix. Mathematical description
- References
- Index
11 - Optical Einstein–Podolsky–Rosen experiments
Published online by Cambridge University Press: 25 January 2010
- Frontmatter
- Contents
- Preface
- 1 Introduction
- 2 Historical milestones
- 3 Basics of the classical description of light
- 4 Quantum mechanical understanding of light
- 5 Light detectors
- 6 Spontaneous emission
- 7 Interference
- 8 Photon statistics
- 9 Squeezed light
- 10 Measuring distribution functions
- 11 Optical Einstein–Podolsky–Rosen experiments
- 12 Quantum cryptography
- 13 Quantum teleportation
- 14 Summarizing what we know about the photon
- 15 Appendix. Mathematical description
- References
- Index
Summary
Polarization entangled photon pairs
Throughout his life, Albert Einstein was never reconciled to quantum theory being an essentially indeterministic description of natural processes, even though he himself contributed fundamental ideas to its development. “God does not play dice” was his inner conviction. In his opinion, quantum theory was only makeshift. His doubts about the completeness of the quantum mechanical description were expressed concisely in a paper published jointly with Podolsky and Rosen (Einstein, Podolsky and Rosen, 1935). This paper analyzes a sophisticated Gedanken experiment, now famous as the Einstein–Podolsky–Rosen paradox, which has excited theoreticians ever since.
The Gedanken experiment was recently realized in a laboratory. The analyzed objects are photon pairs – and this is what has motivated us to dedicate a chapter to this problem which has bearing upon the foundations of quantum mechanics. The photon pairs are formed by two photons generated in sequence (in a so-called cascade transition, as shown in Fig. 11.1). Due to the validity of the angular momentum conservation law (discussed in Section 6.9) for the elementary emission process, the two photons exhibit specifically quantum mechanical correlations, which are incompatible with the classical reality concept, as will be discussed in detail below.
How do the correlations appear in detail? Let us assume the initial state of the atom to be a state with angular momentum (spin) J = 0, the intermediate state to have angular momentum J = 1, and the final state to have again J = 0.
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- Information
- Introduction to Quantum OpticsFrom Light Quanta to Quantum Teleportation, pp. 177 - 200Publisher: Cambridge University PressPrint publication year: 2004