Title:	Complementarity in atomic (finite-level quantum) systems: an information-theoretic approach
Authors:	Srikanth, R. Banerjee, Subhashish
Issue Date:	Feb-2009
Publisher:	EDP Sciences /Springer
Citation:	European Physical Journal D, 2009, Vol.53, p217
Abstract:	We develop an information theoretic interpretation of the number-phase complementarity in atomic systems, where phase is treated as a continuous positive operator valued measure (POVM). The relevant uncertainty principle is obtained as an upper bound on a sum of knowledge of these two observables for the case of two-level systems. A tighter bound characterizing the uncertainty relation is obtained numerically in terms of a weighted knowledge sum involving these variables. We point out that complementarity in these systems departs from mutual unbiasededness in two significant ways: first, the maximum knowledge of a POVM variable is less than log (dimension) bits; second, surprisingly, for higher dimensional systems, the unbiasedness may not be mutual but unidirectional in that phase remains unbiased with respect to number states, but not vice versa. Finally, we study the effect of non-dissipative and dissipative noise on these complementary variables for a single-qubit system.
Description:	Restricted Access. An open-access version is available at arXiv.org (one of the alternative locations)
URI:	http://hdl.handle.net/2289/3799
ISSN:	E-ISSN: 1434-6079 P-ISSN: 1434-6060
Alternative Location:	http://arxiv.org/abs/0711.0875 http://dx.doi.org/10.1140/epjd/e2009-00049-1 http://adsabs.harvard.edu/abs/2009EPJD...53..217S
Copyright:	2009 Springer
Appears in Collections:	Research Papers (TP)

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