Making Large-Scale Quantum Computing PossibleCategory: Science & Technology
Posted: October 29, 2012 06:43AM
At the core of quantum computers are quantum bits or qubits. Unlike electronic bits which are a 0 or a 1, qubits can be both a 0 and a 1 at the same time, which is what gives a quantum computer its parallel computing edge. The number of qubits in a quantum computer also determines just how powerful it is, and researchers at Princeton University have recently found a way to increase this count to new scales.
In this method the researchers used qubits based on electrons and placed them in a semiconductor nanowire. The electrons have some movement along the wire, but not a great deal, which is the key for this. Though electrons are associated exclusively with negative charges, among electrons there are greater and lesser negative charges due to their spin. Two electrons with the same spin repel each other and two electrons with opposite charges attract, just like the poles of a magnet. This attraction and repulsion causes the electrons to collect together or space themselves out along the nanowire. Quantum dots are then formed around the electron pairs to trap them in cages, and that makes the qubits.
By placing more electrons on the semiconductor nanowire, more qubits can be made this way, and the researchers have already demonstrated that the qubits can be controlled and read using microwaves. Before we can see this method employed to create large quantum computers though, it has to be optimized, and the first step to that is improving the microwave optics used.