Three-Color Entanglement

Abstract

Entanglement is an essential quantum resource for the acceleration of information processing as well as for sophisticated quantum communication protocols. Quantum information networks are expected to convey information from one place to another by using entangled light beams. We demonstrated the generation of entanglement among three bright beams of light, all of different wavelengths (532.251, 1062.102, and 1066.915 nanometers). We also observed disentanglement for finite channel losses, the continuous variable counterpart to entanglement sudden death.

Spatial fluctuations in an optical parametric oscillator below threshold with an intracavity photonic crystal

“…Under these approximations, we obtained good agreement between our results and the numerical solution of the full multimode nonlinear model, given by Eqs. (10). In our prototype model, the PC leads to a sinusoidal variation on the refractive index and, therefore, of the detunings that can affect the pump, signal, or both fields, depending on the values of the PC modulations M 0 and M 1 .…”

“…Before we proceed to the analytical evolution of the correlation, we show here an interesting aspect of the signal fluctuations, as obtained by numerical simulations of Eqs. (10). Below threshold, noisy precursors (quantum images) dominate the dynamics, as shown in Fig.…”

Systematic construction of genuine-multipartite-entanglement criteria in continuous-variable systems using uncertainty relations

“…Furthermore, direct calculation of the commutators γ m, α for all tested bipartitions (parameterized by α) shows that γ m, α ≥ 1, so thatγ min = 1. We can then test the three entanglement criteria provided by the set of inequalities (11) in the multipartite form given by Eq. (44).…”

“…A first step in this direction for CV systems was made by van Loock and Furusawa [31] using a variance criterion to test full n−partite inseparability. These criteria do not require reconstruction of the covariance matrix, and for this reason they were preferred to test full n−partite inseparability in most of the CV multipartite states generated in the laboratory [10,11,13,[32][33][34]. However, genuine multipartite entanglement is different from n−partite inseparability, which can be produced by mixing quantum states with fewer that n entangled subsystems.…”

Semiclassical Wigner distribution for a two-mode entangled state generated by an optical parametric oscillator

“…Of special interest is the two-mode entangled state generated in the optical parametric oscillator (OPO) [5], used in many experiments of quantum information and recently shown to produce tripartite continuous variable entanglement [6]. The Wigner distribution of this state was obtained exactly using the solution derived from the complex P-representation (after adiabatic elimination of the pump mode) [7], and tranformed into a Wigner distribution.…”