When we think of computer memories, we either consider the electronic bits in all our devices or we fantasize about the future and consider the qubits, information stored in quantum processes. But now, there’s a new player in town: the “chit”, or chemical bit.
Researchers from the Institute of Physical Chemistry of the Polish Academy of Science were able to encode a single bit of information using chemistry. As reported in Physical Chemistry Chemical Physics, the scientists used a Belousov-Zhabotinsky (BZ) reaction, an oscillatory reaction that begins anew every time it ends.
These reactions are usually accompanied by a color change, due to the catalyst used. The team doped three droplets in a BZ reaction with the element ruthenium, which made the system photosensitive. This allowed the researchers to turn the reaction off at will and control it to produce the desired state. In this way, the researchers created the chit.
“Our idea for the chemical storage of information was simple," co-author Professor Jerzy Gorecki said in a statement. "From our previous experiments, we knew that when Belousov-Zhabotinsky droplets are in contact, chemical fronts can propagate from droplet to droplet. So we decided to look for the smallest droplet systems in which excitations could take place in several ways, with at least two being stable. We could then assign one sequence of excitations a logic value of 0, the other 1, and in order to switch between them and force a particular change of memory state, we could use light.”
Three droplets were placed in a container full of oil just above optical fibers, which were used to control them. The team picked three droplets so they would excite each other, with the chemical front propagating from one to the next. Now, the team had two intervals of times to worry about – the propagation of the reaction from droplet 1 to 2 to 3, and the reaction in each droplet going back to its original state.
The team showed that by carefully selecting time and length of the illumination, they could make sure that these two intervals were the same and the system was constantly in a logic state (‘0’s and ‘1’s). And there’s actually a state ‘2’ when the system is neither in 0 or 1. Better than a classical bit.
Although this is an interesting development, hold on to those silicon chips. You won’t get a “chemical” computer any time soon. The chemical memory only stored information, with the recording and reading still requiring physical methods.