Book contents
- Frontmatter
- Contents
- Preface
- Copyright acknowledgements
- 1 Wave-particle duality
- 2 Cavity quantum electrodynamics
- 3 Quantum nondemolition measurements
- 4 Topological phases
- 5 Macroscopic quantum coherence
- 6 The quantum Zeno paradox
- 7 Testing collapse
- 8 Macroscopic quantum jumps
- 9 Nonlocality
- 10 Tunneling times
- References
- Author index
- Subject index
2 - Cavity quantum electrodynamics
Published online by Cambridge University Press: 27 October 2009
- Frontmatter
- Contents
- Preface
- Copyright acknowledgements
- 1 Wave-particle duality
- 2 Cavity quantum electrodynamics
- 3 Quantum nondemolition measurements
- 4 Topological phases
- 5 Macroscopic quantum coherence
- 6 The quantum Zeno paradox
- 7 Testing collapse
- 8 Macroscopic quantum jumps
- 9 Nonlocality
- 10 Tunneling times
- References
- Author index
- Subject index
Summary
Introduction
Ever since 1916/17 when Einstein argued [45] [46] that spontaneous emission must occur if matter and radiation are to achieve thermal equilibrium, physicists have believed that spontaneous emission is an inherent quantum mechanical property of atoms and that excited atoms inevitably radiate. This view, however, overlooks the fact that spontaneous emission is a consequence of the coupling of quantized energy states of atoms with the quantized radiation field, and is a manifestation of quantum noise or of emission ‘stimulated’ by ‘vacuum fluctuations’. An infinity of vacuum states is available to the photon radiated by an excited atom placed in free space, leading to the effective irreversibility of such emissions. If these vacuum states are modified, as for example by placing an excited atom between closely spaced mirrors or in a small cavity (essentially the Casimir effect), spontaneous emission can be greatly inhibited or enhanced or even made reversible. Recent advances in atomic and optical techniques have made it possible to control and manipulate spontaneous emission. A whole new branch of quantum optics called ‘cavity QED’ has developed since 1987 utilizing these dramatic changes in spontaneous emission rates in cavities to construct new kinds of microscopic masers or micromasers that operate with a single atom and a few photons or with photons emitted in pairs in a two-photon transition.
- Type
- Chapter
- Information
- Testing Quantum Mechanics on New Ground , pp. 37 - 61Publisher: Cambridge University PressPrint publication year: 1999