Check out our new Physical Review Letters paper, in which we have deonstrated a new entanglement measurement technique. This method allows to measure entanglement in a specific type of mixed qubit state without detecting one of the particles. The experiment was performed in the lab of Anton Zeilinger (Physics Nobel Laureate 2022). Other collaborators are Gabriela B. Lemos and Radek Lapkiewicz. A theoretical description of the experiment was published before in Physical Review A.