Please use this identifier to cite or link to this item: http://hdl.handle.net/2289/6395
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dc.contributor.authorPati, Arun Kumar-
dc.contributor.authorSingh, Uttam-
dc.contributor.authorSinha, Urbasi-
dc.date.accessioned2016-09-21T13:45:48Z-
dc.date.available2016-09-21T13:45:48Z-
dc.date.issued2015-11-
dc.identifier.citationPhysical Review A, 2015, Vol.92, p052120en_US
dc.identifier.issn1050-2947-
dc.identifier.issn1094-1622 (online)-
dc.identifier.urihttp://hdl.handle.net/2289/6395-
dc.descriptionOpen Accessen_US
dc.description.abstractIn quantum theory, a physical observable is represented by a Hermitian operator as it admits real eigenvalues. This stems from the fact that any measuring apparatus that is supposed to measure a physical observable will always yield a real number. However, the reality of an eigenvalue of some operator does not mean that it is necessarily Hermitian. There are examples of non-Hermitian operators that may admit real eigenvalues under some symmetry conditions. In general, given a non-Hermitian operator, its average value in a quantum state is a complex number and there are only very limited methods available to measure it. Following standard quantum mechanics, we provide an experimentally feasible protocol to measure the expectation value of any non-Hermitian operator via weak measurements. The average of a non-Hermitian operator in a pure state is a complex multiple of the weak value of the positive-semidefinite part of the non-Hermitian operator. We also prove an uncertainty relation for any two non-Hermitian operators and show that the fidelity of a quantum state under a quantum channel can be measured using the average of the corresponding Kraus operators. The importance of our method is shown in testing the stronger uncertainty relation, verifying the Ramanujan formula, and measuring the product of noncommuting projectors.en_US
dc.language.isoenen_US
dc.publisherAmerican Physical Societyen_US
dc.relation.urihttp://arxiv.org/abs/1406.3007en_US
dc.relation.urihttp://dx.doi.org/10.1103/PhysRevA.92.052120en_US
dc.rights2015 The American Physical Societyen_US
dc.titleMeasuring non-Hermitian operators via weak valuesen_US
dc.typeArticleen_US
Appears in Collections:Research Papers (LAMP)

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