This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: While quantum computing could be the future, it is currently plagued by finicky hardware. To make the technology practical, researchers must demonstrate that it consistently and continuously works and performs at scale.
In a new study, published in Physical Review Letters, researchers at Lawrence Livermore National Laboratory (LLNL) and the Ion Storage Group at the National Institute of Standards and Technology in Boulder, Colorado, created a robust process for entangling trapped-ion qubits. The result means better building blocks for ion-based quantum computers. The approach creates a physical link between two trapped ions.
Those ions are held in place with an electric field, although they do vibrate naturally. Because they have the same charge, they also repel each other. If one ion moves, it nudges its neighbor.
That shared motion can be used as a messenger between the qubits. In this experiment, the team used radio-frequency and microwave electromagnetic fields to apply a force to the ions. In different quantum states—say, when the qubit is pointing up versus down—the force pushes the shared-ion motion in a slightly different way.
As the ions move from this controlled push, they acquire a so-called "phase shift." That phase shift, essentially an angle encoded in the qubits, depends on the combined quantum state of the two ions. With the correct, precisely chosen timing, the motion of the ions fizzles out to end exactly where it started. Now, the ions have a phase shift that depends on their quantum states.
They are linked together, or entangled. "Entanglement is one of the key features that distinguishes quantum computers from classical computers and is central to how quantum advantage can be achieved," said author and LLNL scientist Tyler Guglielmo. "These types of non-classical correlations are what make universal quantum computation possible." Getting the detuning—the gap between the applied electromagnetic force and the natural vibration frequency of the ions—right was the tricky and novel part of the process.
Extract — continue reading at the source.
