Physics

Beyond Heisenberg: Scientists Discover a New Space-Time Limit in Quantum Physics

A collaboration between the University of Regensburg and the Max Planck Institute in Hamburg has revealed a fundamental quantum boundary that links position and time — the more precisely you know when an electron moves, the less tightly it stays confined in space.

• The team used an ultrafast laser system to generate attosecond pulses — one billionth of a billionth of a second — that controlled electrons tunneling between an atomically sharp metal tip and a silver surface separated by only a few atomic diameters. By adjusting the delay between two laser pulses, they reconstructed exactly when each electron crossed the gap.
• They discovered a tradeoff reminiscent of Heisenberg's uncertainty principle: pinning down the timing of an electron's motion with extreme precision inevitably spreads out its quantum wave packet in space. Dubbed a "space-time limit," this effect sets a new boundary on what can be known simultaneously about a particle's location and the moment it moves.
• Beyond its theoretical significance, the finding has practical implications for future electronics and quantum devices. Ultrashort electron control on attosecond timescales is essential for building faster computer chips, room-temperature quantum sensors, and single-molecule imaging tools where knowing both position and timing matters.