Symmetry analyzer for nondestructive Bell-state detection using weak nonlinearities
Symmetry analyzer for nondestructive Bell-state detection using weak nonlinearities
We describe a method to project photonic two-qubit states onto the symmetric and antisymmetric subspaces of their Hilbert space. This device utilizes an ancillary coherent state, together with a weak cross-Kerr non-linearity, generated, for example, by electromagnetically induced transparency. The symmetry analyzer is non-destructive, and works for small values of …