{ "id": "1510.02723", "version": "v1", "published": "2015-10-09T16:09:26.000Z", "updated": "2015-10-09T16:09:26.000Z", "title": "Operator (quasi-)similarity, quasi-Hermitian operators and all that", "authors": [ "Jean-Pierre Antoine", "Camillo Trapani" ], "comment": "16 pages. arXiv admin note: text overlap with arXiv:1409.3497, arXiv:1210.3163, arXiv:1307.5644", "categories": [ "math-ph", "math.MP" ], "abstract": "Motivated by the recent developments of pseudo-Hermitian quantum mechanics, we analyze the structure generated by unbounded metric operators in a Hilbert space. To that effect, we consider the notions of similarity and quasi-similarity between operators and explore to what extent they preserve spectral properties. Then we study quasi-Hermitian operators, bounded or not, that is, operators that are quasi-similar to their adjoint and we discuss their application in pseudo-Hermitian quantum mechanics. Finally, we extend the analysis to operators in a partial inner product space (\\pip), in particular the scale of Hilbert spaces generated by a single unbounded metric operator.", "revisions": [ { "version": "v1", "updated": "2015-10-09T16:09:26.000Z" } ], "analyses": { "subjects": [ "03.65.-w", "03.65.Ca", "02.30.Sa", "02.30.Tb" ], "keywords": [ "pseudo-hermitian quantum mechanics", "similarity", "partial inner product space", "hilbert space", "single unbounded metric operator" ], "note": { "typesetting": "TeX", "pages": 16, "language": "en", "license": "arXiv", "status": "editable" } } }