Qubits tagged posts

An artist’s rendering of the quantum Fredkin (controlled-SWAP) gate, powered by entanglement, operating on photonic qubits. Credit: Raj Patel and Geoff Pryde, Center for Quantum Dynamics, Griffith University.

The quantum circuit Fredkin gate has been experimentally realised for the first time. “Similar to building a huge wall out lots of small bricks, large quantum circuits require very many logic gates to function. However, if larger bricks are used the same wall could be built with far fewer bricks,” said Dr Patel. “We demonstrate in our experiment how one can build larger quantum circuits in a more direct way without using small logic gates.”

At present, even small and medium scale quantum computer circuits cannot be produced because of the requirement to integrate so many of these gate...

A new strategy helps quantum bits stay on task. Credit: Image courtesy of Florida State University

Development of quantum computers may be expedited by collaboration between physicists and chemists. Quantum computer power will dwarf that of today’s machines, with huge implications for cryptography, computational chemistry and other fields. While qubits can take many different forms, the MagLab team worked with carefully designed tungsten oxide molecules that contained a single magnetic holmium ion. The magnetic electrons associated with each holmium ion circulate either clockwise or counterclockwise around the axis of the molecule. These spin states are analogous to the “0s” and “1s” of computer bits...