Full experimental determination of tunneling time with attosecond-scale streaking method

The question of how long a particle takes to tunnel through a potential barrier has sparked a long-standing debate since the early days of quantum mechanics. To solve this problem, scientists in China have proposed and demonstrated a novel attosecond-scale streaking method to accurately determine the tunneling time of an electron from an atom. The experimental results have shown that the tunneling time is close to zero with a precision of a few attoseconds.