dorsal/arxiv
View SchemaQuantum State Diffusion and Time Correlation Functions
| Authors | Todd A. Brun, Nicolas Gisin |
|---|---|
| Categories | |
| ArXiv ID | quant-ph/9512013 |
| URL | https://arxiv.org/abs/quant-ph/9512013 |
| DOI | 10.1080/09500349608232887 |
| Journal | J.Mod.Opt. 43 (1996) 2289 |
Abstract
In computing the spectra of quantum mechanical systems one encounters the Fourier transforms of time correlation functions, as given by the quantum regression theorem for systems described by master equations. Quantum state diffusion (QSD) gives a useful method of solving these problems by unraveling the master equation into stochastic trajectories; but there is no generally accepted definition of a time correlation function for a single QSD trajectory. In this paper we show how QSD can be used to calculate these spectra directly; by formally solving the equations which arise, we arrive at a natural definition for a two-time correlation function in QSD, which depends explicitly on both the stochastic noise of the particular trajectory and the time of measurement, and which agrees in the mean with the ensemble average definition of correlation functions.
{
"annotation_id": "745327ea-7515-4df9-95cb-4040f78dc4d2",
"date_created": "2026-03-02T18:02:37.366000Z",
"date_modified": "2026-03-02T18:02:37.366000Z",
"file_hash": "a20e1b8403dbd709d3e77aee1963e6b0709a6764cd28794a9dee2bb6bee7a56b",
"private": false,
"record": {
"abstract": "In computing the spectra of quantum mechanical systems one encounters the\nFourier transforms of time correlation functions, as given by the quantum\nregression theorem for systems described by master equations. Quantum state\ndiffusion (QSD) gives a useful method of solving these problems by unraveling\nthe master equation into stochastic trajectories; but there is no generally\naccepted definition of a time correlation function for a single QSD trajectory.\nIn this paper we show how QSD can be used to calculate these spectra directly;\nby formally solving the equations which arise, we arrive at a natural\ndefinition for a two-time correlation function in QSD, which depends explicitly\non both the stochastic noise of the particular trajectory and the time of\nmeasurement, and which agrees in the mean with the ensemble average definition\nof correlation functions.",
"arxiv_id": "quant-ph/9512013",
"authors": [
"Todd A. Brun",
"Nicolas Gisin"
],
"categories": [
"quant-ph",
"atom-ph"
],
"doi": "10.1080/09500349608232887",
"journal_ref": "J.Mod.Opt. 43 (1996) 2289",
"title": "Quantum State Diffusion and Time Correlation Functions",
"url": "https://arxiv.org/abs/quant-ph/9512013"
},
"schema_id": "dorsal/arxiv",
"source": {
"execution_id": "deeb96c6-7fad-4fac-bb7f-0a9e1bbb3032",
"id": "arXiv Dataset IDs",
"type": "Model",
"variant": "snapshot-2026-03-01",
"version": "0.1.0"
},
"user_id": 1000002
}