*J. C. Garrison and R. Y. Chiao*

- Published in print:
- 2008
- Published Online:
- September 2008
- ISBN:
- 9780198508861
- eISBN:
- 9780191708640
- Item type:
- chapter

- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198508861.003.0004
- Subject:
- Physics, Atomic, Laser, and Optical Physics

The cavity-mode quantization conjecture of Chapter 2 is replaced by local commutation relations — which are independent of the size and shape of the cavity — between field-operator components. This ...
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The cavity-mode quantization conjecture of Chapter 2 is replaced by local commutation relations — which are independent of the size and shape of the cavity — between field-operator components. This step eliminates the previous dependence on the classical boundary conditions at the ideal cavity wall. The cavity annihilation and creation operators are respectively replaced by the positive- and negative-frequency parts of the vector potential. A simple ad hoc model provides similar results for quantized fields in a passive, linear dielectric. It is shown that the total electromagnetic angular momentum cannot, in general, be expressed as the sum of well defined orbital- and spin-parts. The chapter ends with a discussion of localizability for photons, in which it is shown that there is no photon position operator, no position-space photon wave function, and no local photon number operator.Less

The cavity-mode quantization conjecture of Chapter 2 is replaced by local commutation relations — which are independent of the size and shape of the cavity — between field-operator components. This step eliminates the previous dependence on the classical boundary conditions at the ideal cavity wall. The cavity annihilation and creation operators are respectively replaced by the positive- and negative-frequency parts of the vector potential. A simple *ad hoc* model provides similar results for quantized fields in a passive, linear dielectric. It is shown that the total electromagnetic angular momentum cannot, in general, be expressed as the sum of well defined orbital- and spin-parts. The chapter ends with a discussion of localizability for photons, in which it is shown that there is no photon position operator, no position-space photon wave function, and no local photon number operator.

*Norman J. Morgenstern Horing*

- Published in print:
- 2017
- Published Online:
- January 2018
- ISBN:
- 9780198791942
- eISBN:
- 9780191834165
- Item type:
- chapter

- Publisher:
- Oxford University Press
- DOI:
- 10.1093/oso/9780198791942.003.0002
- Subject:
- Physics, Theoretical, Computational, and Statistical Physics

Focusing on systems of many identical particles, Chapter 2 introduces appropriate operators to describe their properties in terms of Schwinger’s “measurement symbols.” The latter are then factorized ...
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Focusing on systems of many identical particles, Chapter 2 introduces appropriate operators to describe their properties in terms of Schwinger’s “measurement symbols.” The latter are then factorized into “creation” and “annihilation” operators, whose fundamental properties and commutation/anticommutation relations are derived in conjunction with the Pauli exclusion principle. This leads to “second quantization” with the Hamiltonian, number, linear and angular momentum operators expressed in terms of the annihilation and creation operators, as well as the occupation number representation. Finally, the concept of coherent states, as eigenstates of the annihilation operator, having minimum uncertainty, is introduced and discussed in detail.Less

Focusing on systems of many identical particles, Chapter 2 introduces appropriate operators to describe their properties in terms of Schwinger’s “measurement symbols.” The latter are then factorized into “creation” and “annihilation” operators, whose fundamental properties and commutation/anticommutation relations are derived in conjunction with the Pauli exclusion principle. This leads to “second quantization” with the Hamiltonian, number, linear and angular momentum operators expressed in terms of the annihilation and creation operators, as well as the occupation number representation. Finally, the concept of coherent states, as eigenstates of the annihilation operator, having minimum uncertainty, is introduced and discussed in detail.