Measure of Homodyne Nonclassical Area to Quantify the Nonclassicality of Light

We propose a legitimate and easily computable measure of nonclassicality for the states of electromagnetic field based on the standard deviation in the measurement of the homodyne rotated quadrature operator. The proposed measure is the nonclassical area projected by the optical tomogram of the state on the optical tomographic plane. If the nonclassical area projected by the optical tomogram of a quantum state is greater than zero, the state is strictly nonclassical and is zero for the classical state. It is also noted that the nonclassical area of a quantum state increases with an increase in the strength of nonclassicality inducing operations on the state. We have also shown that the nonclassical area measure is robust against environment-induced decoherence of the states. Nonclassical area projected by the optical tomogram of a quantum state of light is experimentally tractable using the balanced homodyne detection of the quadrature operator of the field.