By walking a tightrope between order and chaos, researchers could one day make computer chips work more like the human brain.
Researchers created conditions at the “edge of chaos,” a transition point between order and disorder that allows for rapid information transmission, in an electronic device.
It allowed the scientists to amplify a signal transmitted across a wire without using a separate amplifier — overcoming any signal loss due to electrical resistance. Such a transmission line, which mimics the behavior of superconductors, could make future computer chips simpler and more efficient, the team reported Sept. 11 in the journal Nature.
A computer chip operating at the edge of chaos sounds like it might break down at any moment. But many researchers have theorized that the human brain operates on a similar principle.
Consider a neuron, or nerve cell. Each neuron has an axon, a cable-like appendage that transmits electrical signals to nearby neurons. Those electrical signals help your brain perceive your surroundings and control your body.
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Axons range from 0.04 inches (1 millimeter) to more than 3 feet (1 meter) in length. Transmitting an electrical signal across a wire of the same length leads to signal loss, caused by the resistance of the wire. Computer chip designers get around that issue by inserting amplifiers between shorter wires to boost the signal.
But axons don’t need separate amplifiers — they’re self-amplifying and can transmit electrical signals without much signal loss. Some researchers think that they exist at the edge of chaos, which allows them to amplify small fluctuations in electrical signals without letting those signals grow out of control.
In the new study, scientists mimicked this self-amplifying behavior in a non-biological system. They first established edge-of-chaos conditions on a material called lanthanum cobaltite (LaCoO3). When they applied the right current to the LaCoO3, small fluctuations in the resulting voltage were amplified. The team then tested the conditions on a wire in contact with a sheet of LaCoO3.
They placed two 0.04 inch (1 mm) wires on top of the LaCoO3 and used those to apply the same current to the LaCoO3. That current established the edge-of-chaos conditions. Then they applied an oscillating voltage signal to one end of one of the wires and measured the voltage signal at the other end of the wire. The researchers saw a slight amplification in those voltage fluctuations.
Amplifying such a signal requires additional energy. The scientists found that this energy came from the same source used to maintain the edge of chaos — the applied current. In most electronic components, some of the energy from the applied current dissipates as heat. But at the edge of chaos, a portion of the energy instead amplified the signal.
Operating at the edge of chaos resembles superconductivity, in that the effects of resistance are negligible. The new method could allow superconductor-like behavior at normal temperatures and pressures, the authors said, if the technology is used to create chips in the future.
“Such a solution, which potentially avoids thousands of repeaters and buffers, could greatly alleviate
