BOULDER, Colo. Physicists at the National Institute of Standards and Technology (NIST) have demonstrated the first "universal" programmable quantum information processor able to run any program allowed by quantum mechanicsthe rules governing the submicroscopic worldusing two quantum bits (qubits) of information. The processor could be a module in a future quantum computer, which theoretically could solve some important problems that are intractable today.
The NIST demonstration, described in Nature Physics,* marks the first time any research group has moved beyond demonstrating individual tasks for a quantum processoras done previously at NIST and elsewhereto perform programmable processing, combining enough inputs and continuous steps to run any possible two-qubit program.
The NIST team also analyzed the quantum processor with the methods used in traditional computer science and electronics by creating a diagram of the processing circuit and mathematically determining the 15 different starting values and sequences of processing operations needed to run a given program. "This is the first time anyone has demonstrated a programmable quantum processor for more than one qubit," says NIST postdoctoral researcher David Hanneke, first author of the paper. "It's a step toward the big goal of doing calculations with lots and lots of qubits. The idea is you'd have lots of these processors, and you'd link them together."
The NIST processor stores binary information (1s and 0s) in two beryllium ions (electrically charged atoms), which are held in an electromagnetic trap and manipulated with ultraviolet lasers. Two magnesium ions in the trap help cool the beryllium ions.
NIST scientists can manipulate the states of each beryllium qubit, including placing the ions in a "superposition" of both 1 and 0 values at the same time, a significant potential advantage of information processing in the quantum world. Scientists also can "en
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National Institute of Standards and Technology (NIST)