A recent breakthrough in quantum computing led to the simplification of the Fredkin gate, a building block of quantum computers that was previously too complex to create. Using particles of light, the team was able to create the quantum circuit with less logic operations than previously needed, creating a Fredkin gate in a simplified manner that takes scientists closer to realizing superfast quantum computers.
Raj Patel, first author on the recent study that led to the breakthrough, described the process used to create the gate and its numerous benefits.
"There are no downsides in the sense that it is a valuable tool that you can choose to use or not use when constructing a circuit," he said. "Imagine you want to paint a wall; you could paint it with a small brush or can use a roller. The small brush would get the job done, but the roller will give you broader and more even coverage in less time (i.e. it has many benefits). But if you really had a reason to use the smaller brush it's always an option."
When it comes to quantum circuits, larger gates can be substituted in the place of smaller ones, as is the case with the new Fredkin gate process. In the new study, the team used two quantum logic gates in the place of the six gates that were previously thought needed to construct the circuit.
Despite the promise of the findings, there are still difficulties to overcome.
"The biggest ongoing challenge is to scale these circuits up to perform operations on more qubits (quantum bits of information)," Patel explained. "Ultimately, we'd want to be able to have circuits of hundreds of qubits. The difficulty in doing so is that as the circuits become larger with more qubits they become more susceptible to noise, which can lead to errors."
In order to avoid these errors, scientists in the field are making a global effort to improve the interactions of these physical systems, one method being steering away from large laboratory setups and shifting focus to the creation of miniature quantum circuits that are suitable for chips.
As researchers continue to learn more, they will be able to carry out complex computations that would take standard computers a very long time in a much shorter time span.
"Immediate examples are the factorization of large prime numbers and searching large of unsorted databases," Patel said. "Perhaps the most exciting application is quantum simulation, which would have many applications across science. For instance, it could allow for simulations of complex pharmaceutical drugs containing large molecules without the need to perform trial and error tests in the laboratory.
The findings were published in the March 25 issue of Science Advances.
