dorsal/arxiv
View SchemaProblems about Causality in Fermi's Two-Atom Model and Possible Resolutions
| Authors | Gerhard C. Hegerfeldt |
|---|---|
| Categories | |
| ArXiv ID | quant-ph/9707016 |
| URL | https://arxiv.org/abs/quant-ph/9707016 |
Abstract
In order to check finite propagation speed Fermi, in 1932, had considered two atoms A and B separated by some distance R. At time t=0, A is in an excited state, B in its ground state, and no photons are present. Fermi's idea was to calculate the excitation probability of B. In a model-independent way and with minimal assumptions - Hilbert space and positive energy only - it is proved, not just for atoms but for any systems A and B, that the excitation probability of B is nonzero immediately after t=0. Possible ways out to avoid a contradiction to finite propagation speed are discussed. The notions of strong and weak Einstein causality are introduced.
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"abstract": "In order to check finite propagation speed Fermi, in 1932, had considered two\natoms A and B separated by some distance R. At time t=0, A is in an excited\nstate, B in its ground state, and no photons are present. Fermi\u0027s idea was to\ncalculate the excitation probability of B. In a model-independent way and with\nminimal assumptions - Hilbert space and positive energy only - it is proved,\nnot just for atoms but for any systems A and B, that the excitation probability\nof B is nonzero immediately after t=0. Possible ways out to avoid a\ncontradiction to finite propagation speed are discussed. The notions of strong\nand weak Einstein causality are introduced.",
"arxiv_id": "quant-ph/9707016",
"authors": [
"Gerhard C. Hegerfeldt"
],
"categories": [
"quant-ph"
],
"title": "Problems about Causality in Fermi\u0027s Two-Atom Model and Possible Resolutions",
"url": "https://arxiv.org/abs/quant-ph/9707016"
},
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