TY  - JOUR
A1  - Mari, Andrea
A1  - Kieling, Konrad
A1  - Nielsen, B. Melholt
A1  - Polzik, E. S.
A1  - Eisert, Jens
T1  - Directly estimating nonclassicality
JF  - Physical review letters
N2  - We establish a method of directly measuring and estimating nonclassicality-operationally defined in terms of the distinguishability of a given state from one with a positive Wigner function. It allows us to certify nonclassicality, based on possibly much fewer measurement settings than necessary for obtaining complete tomographic knowledge, and is at the same time equipped with a full certificate. We find that even from measuring two conjugate variables alone, one may infer the nonclassicality of quantum mechanical modes. This method also provides a practical tool to eventually certify such features in mechanical degrees of freedom in opto-mechanics. The proof of the result is based on Bochner's theorem characterizing classical and quantum characteristic functions and on semidefinite programming. In this joint theoretical-experimental work we present data from experimental optical Fock state preparation.
Y1  - 2011
U6  - https://doi.org/10.1103/PhysRevLett.106.010403
SN  - 0031-9007
VL  - 106
IS  - 1
PB  - American Physical Society
CY  - College Park
ER  -