It's
hard to imagine a world that's reached the ceiling for innovation when it comes
to the speed of electronic devices. But that's exactly what a global team of
scientists has done.
The
researchers, from TU Wien, TU Graz, and the Max Planck Institute of Quantum
Optics, calculated the ultimate speed limit for electronic devices, the point
at which the laws of quantum mechanics prevent microchips from becoming any
faster, according to a study published in Nature Communications.
The
fastest devices in the world are known as optoelectronics — systems that use
light to control electricity. The new study outlines the limit for
optoelectronics by calculating the speed at which the most powerful examples of
these devices can operate.
To make
their calculations, the team experimented with semiconductor materials and
lasers. A quick laser pulse energizes electrons in the material before a
second, slightly longer lase pulse produces an electrical current in the
material. The researchers observed the current while applying shorter and
shorter laser pulses until Heisenberg's uncertainty principle allowed them to
go no further — the principle states that the more accurately you measure one
variable of a particle, such as its position, the more uncertain other variables,
such as momentum will be, and vice versa.
The
researchers also applied their findings to complex computer simulations to make
better sense of their observations. Using shorter laser pulses meant the
researchers could calculate exactly when the electrons gained energy. But, due
to Heisenberg's principle, this came at the cost of reduced certainty over the
amount of energy gained. That would likely be an insurmountable hurdle for
electronic devices, which require exact calculations of electrons to be
controlled precisely.
So,
according to the researchers, the upper limit of optoelectronic systems is one
Petahertz, which is equivalent to a million Gigahertz. To go any faster would
be to break the laws of quantum physics.
The team
does also state that many other technical hurdles would stand in the way of
getting anywhere near that speed, so we're not about to see optoelectronic
devices that come anywhere near that upper limit.
"Realistic technical upper limits are most likely considerably lower," the scientists say in a press release. "Even though the laws of nature determining the ultimate speed limits of optoelectronics cannot be outsmarted, they can now be analyzed and understood with sophisticated new methods." Knowing the ceiling allows researchers and developers to better understand the constraints they're working with and adjust their work accordingly.
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