TY - JOUR
T1 - Reflection symmetries for multiqubit density operators
JF - J. Math. Phys. 47 (2006) 032104
Y1 - 2006
A1 - Claudio Altafini
A1 - Timothy F. Havel
AB - For multiqubit density operators in a suitable tensorial basis, we show that a number of nonunitary operations used in the detection and synthesis of entanglement are classifiable as reflection symmetries, i.e., orientation changing rotations. While one-qubit reflections correspond to antiunitary symmetries, as is known for example from the partial transposition criterion, reflections on the joint density of two or more qubits are not accounted for by the Wigner Theorem and are well-posed only for sufficiently mixed states. One example of such nonlocal reflections is the unconditional NOT operation on a multiparty density, i.e., an operation yelding another density and such that the sum of the two is the identity operator. This nonphysical operation is admissible only for sufficiently mixed states.
UR - http://hdl.handle.net/1963/2121
U1 - 2122
U2 - Mathematics
U3 - Functional Analysis and Applications
ER -