We show that the coherent superposition τa+τa+ of photon subtraction and addition applied to each local mode of a two-mode entangled state can enhance the nonlocality manifested by the violation of a Bell inequality. A twomode squeezed state is used as an input state for this demonstration with four different Bell inequalities employed: Bell inequalities adopting displaced parity operator, pseudospin operator, homodyne measurement, and conditional entropy, respectively. We find that the coherent operation significantly enhances the nonlocality remarkably in the weak squeezing limit, compared with other possible non-Gaussian operations. It can also give a maximal Bell violation with a very small squeezing for the inequalities with pseudospin operator and conditional entropy.
|Number of pages||6|
|Journal||Journal of the Optical Society of America B: Optical Physics|
|Publication status||Published - 1 May 2012|
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Statistical and Nonlinear Physics