Electrons caught obeying a space-time limit at attosecond speeds

Regensburg-led experiments show electron position and timing can't both be pinned down exactly, a finding tied to far faster future electronics.

Researchers at the University of Regensburg, working with partners including a Max Planck Institute team in Hamburg, report experimental evidence of a "space-time limit" for electrons. Where an electron is and when it moves cannot both be fixed with arbitrary precision. Heisenberg's uncertainty principle already limits position and momentum together, but it does not set the same restriction on position and time, so this is a separate constraint. The work involves groups led by Jascha Repp, Rupert Huber, Franz Giessibl and Klaus Richter, plus Angel Rubio's team. Simon Maier is lead author.

In the experiment, timed laser pulses drive electrons from a very sharp metal tip across a gap of a few atomic diameters to a silver surface. The movement shows up as electrical current. Two light pulses separated by a controlled interval reveal when the electrons move, and varying that interval showed motion on attosecond timescales. An attosecond is a billionth of a billionth of a second. The electrons crossed the barrier by quantum tunneling, behaving as waves. Quantum simulations from Rubio's team closely matched the data and put the electron motion about 500 attoseconds behind the light field.

The abundance angle is indirect. Computing gets cheaper when switching speed and energy cost improve, and knowing the physical floor on how finely electron motion can be timed and placed tells engineers what any ultrafast device can achieve. The source says the findings could lead to electronics hundreds of thousands of times faster than today's, and to control over chemical reactions.

Treat those figures as prospects. This is a lab measurement of electrons in a tip-and-surface setup, not a device, and no product or cost reduction has been shown. The summary we saw is a university press release and was cut off mid-sentence, so later details are missing. Watch for peer-reviewed follow-ups and any attempt to build circuits on these timescales.

Source: ScienceDaily