A new study conducted by researchers from Griffith University and the University of Queensland has revealed how to simplify the quantum Fredkin gate, a challenging quantum computing circuit that was previously too complex to build. The simplification of the Fredkin gate, one of the building blocks of a quantum computer, might make the creation of functional quantum computers a more feasible option than previously believed.
"The allure of quantum computers is the unparalleled processing power that they provide compared to current technology," said Raj Patel, first author on the study.
Quantum computers are much more complex than traditional computers. Whereas traditional designs possess bits that represent either a zero or a one, quantum computers possess atom-sized bits that can represent zero, one or a combination of both at the same time, called a "superposition." This means that quantum computers require the incorporation of a large amount of smaller parts in order for them to run.
"Similar to building a huge wall out of lots of small bricks, large quantum circuits require very many logic gates to function," Patel said. "However, if larger bricks are used the same wall could be built with far fewer bricks."
"We demonstrate in our experiment how one can build larger quantum circuits in a more direct way without using small logic gates," he added.
Fredkin gates are a location in quantum computer circuits where bits can be changed or swapped depending on a third value. Although they previously required five logic operations to build, the new study reveals a simplified process that achieves its creation with less logic operations by using particles of light.
"The research team used the quantum entanglement of photons - particles of light - to implement the controlled-SWAP operation directly," the team said.
Quantum computers provide a level of processing power that is highly sought after by scientists and governments for their utility during activities such as air traffic control models and molecular compositions due to the high level of power that they require.
If quantum computers are realized, they will be able to solve a problem that would take a traditional computer 10,000 years in just one second.
The findings were published in the March 25 issue of Science Advances.