dorsal/arxiv
View SchemaContinuous Time-Dependent Measurements: Quantum Anti-Zeno Paradox with Applications
| Authors | A. P. Balachandran, S. M. Roy |
|---|---|
| Categories | |
| ArXiv ID | quant-ph/0102019 |
| URL | https://arxiv.org/abs/quant-ph/0102019 |
| DOI | 10.1142/S0217751X0201056X |
| Journal | Int.J.Mod.Phys.A17:4007-4024,2002 |
Abstract
We derive differential equations for the modified Feynman propagator and for the density operator describing time-dependent measurements or histories continuous in time. We obtain an exact series solution and discuss its applications. Suppose the system is initially in a state with density operator $\rho(0)$ and the projection operator $E(t) = U(t) E U^\dagger(t)$ is measured continuously from $t = 0$ to $T$, where $E$ is a projector obeying $E\rho(0) E = \rho(0)$ and $U(t)$ a unitary operator obeying $U(0) = 1$ and some smoothness conditions in $t$. Then the probability of always finding $E(t) = 1$ from $t = 0$ to $T$ is unity. Generically $E(T) \neq E$ and the watched system is sure to change its state, which is the anti-Zeno paradox noted by us recently. Our results valid for projectors of arbitrary rank generalize those obtained by Anandan and Aharonov for projectors of unit rank.
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"abstract": "We derive differential equations for the modified Feynman propagator and for\nthe density operator describing time-dependent measurements or histories\ncontinuous in time. We obtain an exact series solution and discuss its\napplications. Suppose the system is initially in a state with density operator\n$\\rho(0)$ and the projection operator $E(t) = U(t) E U^\\dagger(t)$ is measured\ncontinuously from $t = 0$ to $T$, where $E$ is a projector obeying $E\\rho(0) E\n= \\rho(0)$ and $U(t)$ a unitary operator obeying $U(0) = 1$ and some smoothness\nconditions in $t$. Then the probability of always finding $E(t) = 1$ from $t =\n0$ to $T$ is unity. Generically $E(T) \\neq E$ and the watched system is sure to\nchange its state, which is the anti-Zeno paradox noted by us recently. Our\nresults valid for projectors of arbitrary rank generalize those obtained by\nAnandan and Aharonov for projectors of unit rank.",
"arxiv_id": "quant-ph/0102019",
"authors": [
"A. P. Balachandran",
"S. M. Roy"
],
"categories": [
"quant-ph",
"gr-qc",
"hep-th"
],
"doi": "10.1142/S0217751X0201056X",
"journal_ref": "Int.J.Mod.Phys.A17:4007-4024,2002",
"title": "Continuous Time-Dependent Measurements: Quantum Anti-Zeno Paradox with Applications",
"url": "https://arxiv.org/abs/quant-ph/0102019"
},
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