On the two-copy distillability of Werner states and a new partial trace inequality

Thomas C. Fraser, Felix Huber, Balázs Pozsgay +1

Problem 5 in {\it Five Open Problems in Quantum Information Theory} [PRX Quantum 3, 010101 (2022)], asks whether the two-ququart Werner state $\varrho (4,-\frac{1}{2})$ is two-copy dis…