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Strategies & Market Trends : 2026 TeoTwawKi ... 2032 Darkest Interregnum -- Ignore unavailable to you. Want to Upgrade?

To: TobagoJack who wrote (98898)	3/1/2013 7:59:20 AM
From: dvdw©	Read Replies (1) \| Respond to of 217774

Let nothing befuddle awareness. Projection Operators will have thier way. All Prices remain Artifacts of prevailing systems intent. Archive the following as permanent reference within your characterization library. The Reduced density matrices The idea of a reduced density matrix was introduced by Paul Dirac in 1930. [35] Consider as above systems and each with a Hilbert space , . Let the state of the composite system be As indicated above, in general there is no way to associate a pure state to the component system . However, it still is possible to associate a density matrix. Let . which is the projection operator onto this state. The state of is the partial trace of over the basis of system : . is sometimes called the reduced density matrix of on subsystem A. Colloquially, we "trace out" system B to obtain the reduced density matrix on A. For example, the reduced density matrix of for the entangled state discussed above is This demonstrates that, as expected, the reduced density matrix for an entangled pure ensemble is a mixed ensemble. Also not surprisingly, the density matrix of for the pure product state discussed above is e