Scientists Determine Absolute Quantum Speed Limit For Electronics

It often feels like electronics will continue to get faster forever, but at some point the laws of physics will intervene to put a stop to that. Now scientists have calculated the ultimate speed limit – the point at which quantum mechanics prevents microchips from getting any faster, Michael Irving reported for New Atlas.

Photo Insert: A diagram illustrating how ultra-short laser pulses (blue) give electrons in a semiconductor vitality, then a second laser pulse (crimson) sends them flying off in sure instructions to provide an electrical present

It’s well known that nothing moves faster than light, and that holds true for electronics – systems that use light to control electricity, known as optoelectronics, are the fastest devices.

And in the new study, researchers from TU Wien, TU Graz, and the Max Planck Institute of Quantum Optics have identified the upper limit for how fast optoelectronics could possibly get. The research was published in the journal Nature Communications.

The team conducted experiments using semiconductor materials and lasers. The semiconductor is hit with an ultra-short laser pulse, which shifts electrons in the material into a higher energy state, allowing them to move around freely.

Then, a second, slightly longer laser pulse sends them shooting off in a certain direction, producing an electrical current.

Using this technique, as well as complex computer simulations, the team hit semiconductors with shorter and shorter laser pulses. But at a certain point, the process begins to bump up against Heisenberg’s uncertainty principle – this is the strange quantum quirk where the more accurately you measure one characteristic of a particle, the less you can be sure of another.

The team calculated the absolute upper limit for how fast optoelectronic systems could possibly ever get – one Petahertz, which is a million Gigahertz. That’s a hard limit, one that can’t be engineered around because the barrier is baked into the very laws of quantum physics.

Of course, it’s unlikely we’ll ever actually have to directly worry about that anyway. The team says that other technological hurdles would arise long before optoelectronic devices reach the realm of PHz. But understanding the hard limit could help develop better electronics.

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