Heralded Generation of Maximally Entangled State of Open Qubits Coupled to a 1D Environment

Maximally entangled states are of central importance in quantum information science and in modern quantum technologies. Here we show that heralded generation of a maximally entangled state of two intrinsically open qubits can be realized in a one-dimensional (1d) system with strong coherent driving and continuous monitoring. In contrast to the common belief that system-environment interaction leads to decoherence and so destroys quantum effects, continuous measurement and strong interference in our 1d system generates a pure state with perfect quantum correlation between the two open qubits. Another surprise is that this maximally entangled state survives the strong coherent state input, which is a classical state that overwhelms the whole system.