Direct estimations of linear and nonlinear functionals of a quantum state.
We present a simple quantum network, based on the controlled-SWAP gate, that can extract certain properties of quantum states without recourse to quantum tomography. It can be used as a basic building block for direct quantum estimations of both linear and nonlinear functionals of any density operat...
| Main Authors: | , , , , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
2002
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