Pathway provided to scalable quantum architectures with non-local quantum gates - General Developments - Brief Article

Journal of Research of the National Institute of Standards and Technology, May-June, 2003

One of the basic requirements for building a scalable quantum computer is the need to interact arbitrary pairs of qubits (quantum bits) within the computer. However, most quantum interactions have only a short range, limiting interactions between qubits to those that are nearest neighbors. A chain of interactions between neighboring qubits would be required to connect distant qubits, which would be a burdensome communication cost.

In a recently submitted paper, three NIST scientists have shown how one can efficiently solve this quantum communication problem by using a set of ancillary quantum bits to create a distant pair of entangled qubits. This entangled pair of atoms, or quantum resource, then can be used to efficiently perform or teleport a non-local quantum gate between any two distant qubits. The paper shows that this concept is robust even in the presence of quantum noise and decoherence.

This new concept effectively provides a means of building a quantum bus, a concept very similar to the classical bus connecting the basic architectural elements of the von Neumann computer. Together with the key building blocks of a quantum computer, the quantum bus provides a pathway to a scalable quantum architecture using non-local interactions.

CONTACT: Carl Williams, (301) 975-3531; carl.williams@nist.gov.