Quantum Computing Breakthrough

An international team has identified a new hybrid atom that could be used to develop quantum computers. This data visualization shows an electron density map of the material. The funnel- or vortex-shaped figure in the lower left is an arsenic atom, and the saucer-shaped image in the center is a map of an electron binding to various atoms (each dot represents one location). The yellow dots in the upper left-center are the electron in the quantum state.

The odd behavior of a molecule in an experimental silicon computer chip has led to a discovery that opens the door to quantum computing in semiconductors. in a Nature Physics journal paper currently online, the researchers describe how they have created a new, hybrid molecule in which its quantum state can be intentionally manipulated - a required step in the building of quantum computers."Up to now large-scale quantum computing has been a dream," says Gerhard Klimeck, professor of electrical and computer engineering at Purdue University and associate director for technology for the national Network for Computational Nanotechnology."This development may not bring us a quantum computer 10 years faster, but our dreams about these machines are now more realistic." The workings of traditional computers haven't changed since they were room-sized behemoths 50 years ago; they still use bits of information, 1s and 0s, to store and process information. Quantum computers would harness the strange behaviors found in quantum physics to create computers that would carry information using quantum bits, or qubits. Computers would be able to process exponentially more information.If a traditional computer were given the task of looking up a person's phone number in a telephone book, it would look at each name in order until it found the right number. Computers can do this much faster than people, but it is still a sequential task. A quantum computer, however, could look at all of the names in the telephone book simultaneously. Albert Einstein, in a letter to Erwin Schrödinger in the 1930s, wrote that in a quantum state a keg of gunpowder would have both exploded and unexploded molecules within it (a notion that led Schrödinger to create his famous cat-in-a-box thought experiment).This "neither here nor there" quantum state is what can be controlled in this new molecule simply by altering the voltage of the transistor. Until now, the challenge had been to create a computer semiconductor in which the quantum state could be controlled, creating a qubit. "Our experiment made us realize that industrial electronic devices have now reached the level where we can study and manipulate the state of a single atom," Rogge says. "This is the ultimate limit, you can not get smaller than that."