Entanglement properties of a tunable non-Gaussian quantum state by virtue of multi-photon conditional measurement

Abstract

In this work, we present a theoretical scheme for generating a new kind of tunable non-Gaussian entangled state, by means of beam splitters and multi-photon conditional measurement with two-mode squeezed vacuum state (TMSVS) inputs. The output state is proven to be two-variable Hermite polynomial excited squeezed vacuum states, whose success probability of detection relates to the Jacobi polynomials. We then mainly study the entanglement properties of the output state for the symmetric case quantified by the von Neumann entropy and Einstein-Podolsky-Rosen correlation. It is shown that the entropy of entanglement is valid for verifying the improvement of entanglement within a certain range of squeezing parameter and transmissivity, and the resulting state case may possess a stronger correlation than the initial TMSVS by increasing the transmissivity or photon number of detection. In addition, the violation of the Clauser-Horne-Shimony-Holt (CHSH) inequality for the output state is also evaluated in terms of Wigner representation in phase space. It is found that the negative region of Wigner function distribution becomes more visible with the increase of the photon number of detection, and the degree of the violation of the CHSH inequality significantly increases as the photon number of detection for the symmetrical case increases. The resulting state with highly nonclassical characteristics will provide a useful application in the fields of quantum information processing.

Bullet-alike arrays for TE-one/TM-two splitting under second Bragg incidence at communication laser wavelength

“…As figure 3 shows, efficiencies more than 95% in the -2nd order for TE polarization and 40% in the 0th and the -2nd order for TM polarization can be achieved within the incident angle range of 49.9-51.4 • . The fabrication variation of grating period will have some influence on the performance for the polarization-selective beam splitter [25][26][27][28][29]. Figure 4 shows reflective efficiency of a polarization-selective grating versus grating period.…”

Generating superpositions of quantum states via a beam splitter with position measurement

“…Many recent studies have examined the relationship between the degree of nonclassicality of non-Gaussian states and different variables, such as various parameters of input quantum states and the choice of different transmissivity BS [31][32][33]. However, as far as we know, due to the lack of a suitable quantum representation, most of these studies have only been carried out in approximate analysis, i.e., the small input photon number or the near zero position detection [34].…”

Nonclassicality and teleportation fidelity of coherent photon-subtracted two-mode squeezed thermal states

“…To satisfy the requirement of quantum information protocols for long-distance communication, there have been suggestions and realizations for engineering the quantum states, which are plausible ways to conditionally manipulate a nonclassical state of an optical field [13][14][15][16][17][18][19][20]. The coherent photon subtraction proposed in this paper is an effective de-Gaussian protocols which can be implemented with beam splitters and photon detectors to generate non-Gaussianity from conventional Gaussian states.…”