dorsal/arxiv
View SchemaDecoherence without dissipation?
| Authors | Dominique Gobert, Jan von Delft, Vinay Ambegaokar |
|---|---|
| Categories | |
| ArXiv ID | quant-ph/0306019 |
| URL | https://arxiv.org/abs/quant-ph/0306019 |
| DOI | 10.1103/PhysRevA.70.026101 |
Abstract
In a recent article, Ford, Lewis and O'Connell (PRA 64, 032101 (2001)) discuss a thought experiment in which a Brownian particle is subjected to a double-slit measurement. Analyzing the decay of the emerging interference pattern, they derive a decoherence rate that is much faster than previous results and even persists in the limit of vanishing dissipation. This result is based on the definition of a certain attenuation factor, which they analyze for short times. In this note, we point out that this attenuation factor captures the physics of decoherence only for times larger than a certain time t_mix, which is the time it takes until the two emerging wave packets begin to overlap. Therefore, the strategy of Ford et al of extracting the decoherence time from the regime t < t_mix is in our opinion not meaningful. If one analyzes the attenuation factor for t > t_mix, one recovers familiar behaviour for the decoherence time; in particular, no decoherence is seen in the absence of dissipation. The latter conclusion is confirmed with a simple calculation of the off-diagonal elements of the reduced density matrix.
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"abstract": "In a recent article, Ford, Lewis and O\u0027Connell (PRA 64, 032101 (2001))\ndiscuss a thought experiment in which a Brownian particle is subjected to a\ndouble-slit measurement. Analyzing the decay of the emerging interference\npattern, they derive a decoherence rate that is much faster than previous\nresults and even persists in the limit of vanishing dissipation. This result is\nbased on the definition of a certain attenuation factor, which they analyze for\nshort times. In this note, we point out that this attenuation factor captures\nthe physics of decoherence only for times larger than a certain time t_mix,\nwhich is the time it takes until the two emerging wave packets begin to\noverlap. Therefore, the strategy of Ford et al of extracting the decoherence\ntime from the regime t \u003c t_mix is in our opinion not meaningful. If one\nanalyzes the attenuation factor for t \u003e t_mix, one recovers familiar behaviour\nfor the decoherence time; in particular, no decoherence is seen in the absence\nof dissipation. The latter conclusion is confirmed with a simple calculation of\nthe off-diagonal elements of the reduced density matrix.",
"arxiv_id": "quant-ph/0306019",
"authors": [
"Dominique Gobert",
"Jan von Delft",
"Vinay Ambegaokar"
],
"categories": [
"quant-ph"
],
"doi": "10.1103/PhysRevA.70.026101",
"title": "Decoherence without dissipation?",
"url": "https://arxiv.org/abs/quant-ph/0306019"
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