Scientists at the prestigious US MIT and Los Alamos National Labs recently announced that they've developed the first quantum computer able to simulate a quantum system. The prototype can only count to 4, but its creation is a milestone on the road to real quantum computers.
After languishing for more than a decade, quantum research gained momentum in 1994 when Peter Shor, a scientist at AT&T Labs, showed that a quantum computer could be programmed to break an important kind of code exponentially faster than existing computers. The floodgates of research interest opened all over the world, leading to a recent breakthrough.
The Nobel Prize-winning physicist Richard Feynman suggested in 1982 the possiblity of a new kind of computer that would exploit the quantum properties of matter. Such a computer would represent data as quantum bits (qubits) instead of ordinary bits. Qbits aren't limited to being either 0 or 1. Rather, they can be in a mixed state of on and off. The result: built-in massive parallel computing.
Quantum computers are uniquely powerful because qubits can interact with each other, giving rise to exponential increases in power. In conventional computing, the power of a processor increases additively with each bit, but in quantum computing, an added qubit multiplies the potential power of the processor, doubling or even quadrupling its capability.
A Simple Experiment
The group of researchers, including Raymond LaFlamme of Los Alamos, and David Cory and Ching-Hua Tseng of MIT, have developed a general framework for quantum simulation that could be adapted to any quantum computer. Tseng explains that the experiment they did was "very simple...a first-year quantum mechanics student could do it on paper. But this is probably the first reachable application of information processing on a quantum system."
Cory says that we're at the very beginning of the era of quantum transducers but cautions that "we're still in the early stages of integrating information theory into quantum mechanics." Nonetheless, he suggests that there may even be a quantum improvement to Moore's Law, which refers to the doubling of computer power every eighteen months. "In the last two years we've gone from two qubits to six qubits. This is a sixteenfold increase in computer power. We may have 10 qubits in 2001, another sixteenfold increase."
Even adding two qubits a year, though, quantum computers are years away from rivaling existing supercomputers, equivalent in power to a 40-qubit machine.
