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Full-Text Articles in Physics
Static And Dynamic Casimir Effect Instabilities, Y. N. Srivastava, A. Widom, S. Sivasubramanian, M. Pradeep Ganesh
Static And Dynamic Casimir Effect Instabilities, Y. N. Srivastava, A. Widom, S. Sivasubramanian, M. Pradeep Ganesh
Allan Widom
The static Casimir effect concerns quantum electrodynamic induced Lamb shifts in the mode frequencies and thermal free energies of condensed matter systems. Sometimes, the condensed matter constitutes the boundaries of a vacuum region. The static frequency shift effects have been calculated in the one photon loop perturbation theory approximation. The dynamic Casimir effect concerns two photon radiation processes arising from time dependent frequency modulations again computed in the one photon loop approximation. Under certain conditions the one photon loop computation may become unstable and higher order terms must be invoked to achieve stable solutions. This stability calculation is discussed for …
Acuasal Behavior In Quantum Electrodynamics, A. Widom, Y. N. Srivastava, E. Sassaroli
Acuasal Behavior In Quantum Electrodynamics, A. Widom, Y. N. Srivastava, E. Sassaroli
Allan Widom
Acausal features of quantum electrodynamic processes are discussed. While these processes are not present for the classical electrodynamic theory, in the quantum electrodynamic theory, acausal processes are well known to exist. For example, any Feynman diagram with a "loop" in space-time describes a "particle" which may move forward in time or backward in time or in space-like directions. The engineering problems involved in experimentally testing such causality violations on a macroscopic scale are explored.
Causality And Electromagnetic Transmissions Through Materials, V. Kidambi, A. Widom
Causality And Electromagnetic Transmissions Through Materials, V. Kidambi, A. Widom
Allan Widom
There have been several experiments which hint at evidence for superluminal transport of electromagnetic energy through a material slab. On the theoretical side, it has appeared evident that acausal signals are indeed possible in quantum electrodynamics. However, it is unlikely that superluminal signals can be understood on the basis of a purely classical electrodynamic signals passing through a material. The classical and quantum theories represent quite different views, and it is the quantum view which may lead to violations of Einstein causality.