dorsal/arxiv
View SchemaWeak Values and Consistent Histories in Quantum Theory
| Authors | R. E. Kastner |
|---|---|
| Categories | |
| ArXiv ID | quant-ph/0207182 |
| URL | https://arxiv.org/abs/quant-ph/0207182 |
Abstract
A relation is obtained between weak values of quantum observables and the consistency criterion for histories of quantum events. It is shown that ``strange'' weak values for projection operators (such as values less than zero) always correspond to inconsistent families of histories. It is argued that using the ABL rule to obtain probabilities for counterfactual measurements corresponding to those strange weak values gives inconsistent results. This problem is shown to be remedied by using the conditional weight, or pseudo-probability, obtained from the multiple-time application of Luders' Rule. It is argued that an assumption of reverse causality (a form of time symmetry) implies that weak values obtain, in a restricted sense, at the time of the weak measurement as well as at the time of post-selection. Finally, it is argued that weak values are more appropriately characterised as multiple-time amplitudes than expectation values, and as such can have little to say about counterfactual questions.
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"abstract": "A relation is obtained between weak values of quantum observables and the\nconsistency criterion for histories of quantum events. It is shown that\n``strange\u0027\u0027 weak values for projection operators (such as values less than\nzero) always correspond to inconsistent families of histories. It is argued\nthat using the ABL rule to obtain probabilities for counterfactual measurements\ncorresponding to those strange weak values gives inconsistent results. This\nproblem is shown to be remedied by using the conditional weight, or\npseudo-probability, obtained from the multiple-time application of Luders\u0027\nRule. It is argued that an assumption of reverse causality (a form of time\nsymmetry) implies that weak values obtain, in a restricted sense, at the time\nof the weak measurement as well as at the time of post-selection. Finally, it\nis argued that weak values are more appropriately characterised as\nmultiple-time amplitudes than expectation values, and as such can have little\nto say about counterfactual questions.",
"arxiv_id": "quant-ph/0207182",
"authors": [
"R. E. Kastner"
],
"categories": [
"quant-ph"
],
"title": "Weak Values and Consistent Histories in Quantum Theory",
"url": "https://arxiv.org/abs/quant-ph/0207182"
},
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