18 qubits entangle using six photons | NextBigFuture.com

Arxiv – 18-qubit entanglement with photon’s three degrees of freedom They used * 30 single-photon interferometers in total. * The outputs are detected by 48 single-photon detectors Scheme and experimental setup for creating and verifying 18-qubit GHZ state consisting of six photons and three degrees of freedom. a. The generation of six-photon polarization-entangled GHZ state. An ultrafast laser with a central wavelength of 788 nm, a pulse duration of 120 fs and a repetition rate of 76 MHz is focused on a lithium triborate (LBO) and up-converted to 394 nm. The ultraviolet laser is focused on three custom-designed sandwich-like nonlinear