001035359 001__ 1035359
001035359 005__ 20250110192857.0
001035359 0247_ $$2arXiv$$aarXiv:2408.14637
001035359 037__ $$aFZJ-2025-00406
001035359 088__ $$2arXiv$$aarXiv:2408.14637
001035359 1001_ $$0P:(DE-HGF)0$$aMankodi, Ishan N. H.$$b0
001035359 245__ $$aPerturbative power series for block diagonalisation of Hermitian matrices
001035359 260__ $$c2025
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001035359 500__ $$a7 pages, 1 figure
001035359 520__ $$aBlock diagonalisation of matrices by canonical transformation is important in various fields of physics. Such diagonalization is currently of interest in condensed matter physics, for modelling of gates in superconducting circuits and for studying isolated quantum many-body systems. While the block diagonalisation of a particular Hermitian matrix is not unique, it can be made unique with certain auxiliary conditions. It has been assumed in some recent literature that two of these conditions, ``least action' vs. block-off-diagonality of the generator, lead to identical transformations. We show that this is not the case, and that these two approaches diverge at third order in the small parameter. We derive the perturbative power series of the ``least action', exhibiting explicitly the loss of block-off-diagnoality.
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001035359 7001_ $$0P:(DE-Juel1)143759$$aDiVincenzo, David P.$$b1$$ufzj
001035359 909CO $$ooai:juser.fz-juelich.de:1035359$$pVDB
001035359 9101_ $$0I:(DE-588b)5008462-8$$6P:(DE-Juel1)143759$$aForschungszentrum Jülich$$b1$$kFZJ
001035359 9131_ $$0G:(DE-HGF)POF4-522$$1G:(DE-HGF)POF4-520$$2G:(DE-HGF)POF4-500$$3G:(DE-HGF)POF4$$4G:(DE-HGF)POF$$9G:(DE-HGF)POF4-5221$$aDE-HGF$$bKey Technologies$$lNatural, Artificial and Cognitive Information Processing$$vQuantum Computing$$x0
001035359 9141_ $$y2025
001035359 920__ $$lyes
001035359 9201_ $$0I:(DE-Juel1)PGI-2-20110106$$kPGI-2$$lTheoretische Nanoelektronik$$x0
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