Quantum computing, which promises to perform calculations
too difficult for even the most powerful supercomputers, is a step closer to
reality. Proving a solid-state quantum computer can be built, a Yale
University research team has
successfully tested a two-qubit processor in a rudimentary search algorithm, according
to Yale and the National Science Foundation.
Qubits, short for quantum bits, are made of artificial
atoms. In the Yale research, each qubit was made up of a billion or so aluminum
atoms, but acted like a single atom. While the transistors in classical
microchips can either be on or off, representing a 1 or 0 in binary notation,
quantum mechanics allows atoms to be in multiple states at once, enabling
greater data storage and processing power.
“This lets you parallelize computation,” said Leo DiCarlo, a
post-graduate researcher at Yale and a project team member.
Scientists are particularly interested in quantum computers
because they are expected to model solid-state systems, proteins and chemical
reactions. In addition, a quantum computer could search unstructured databases
or reduce very large numbers to prime factors, said DiCarlo.
“A quantum computer is not going to be a general-purpose
computer, but one that’s suited to solve very specific problems,” said the
researcher.
As in all computers, cooling is important. A quantum
computer relies on superconductivity, which can only be achieved by cooling the
computing materials to nearly absolute zero (0 degrees Kelvin).
Key to the advance was getting the qubits to maintain their
state for far longer than was previously possible—a microsecond, compared with
a nanosecond previously. The group will
now work to increase the number of qubits and extend the state of the qubits to
run more complex algorithms.
The work was supported in part by the Yale Center for
Quantum and Information Physics (CQUIP), funded by a grant from the National
Science Foundation's Division of Materials Research and Division of Physics,
and by the Army Research Office and National Security Agency.
