By SCOTT DEWING
Published: January 2005

WHEN I WAS A CHILD, the atomic world was both simple and ominous. An atom was made up of protons, neutrons and electrons. The protons and neutrons were clumped together in the middle and the electrons revolved around the central clump just like the moon revolved around the earth and the earth revolved around the sun. The unseen world then was really not much different than the world I could see at night, lying on my back in the yard with the coldness of the earth pressing against my shoulder-blades and the coldness of an infinite yet mostly empty universe pressing down upon my eyes.

The atomic world was ominous too because a man named Oppenheimer had led a team of scientists who figured out how to split an atom in half. When an atom was split like that it resulted in a tremendous release of energy, an explosion that was 10,000 times hotter than the surface of the sun. As a child in the midst of the Cold War, I knew that there were missiles on the other side of the world with that atomic power in them. The missiles were aimed at me in my backyard.

Some years later, I studied quantum physics and learned that my childhood atomic model was wrong. The atomic world was far more complicated. Electrons didn’t “orbit” the nucleus but existed only within probable states. You couldn’t know everything about these probabilities because of this principle called Heisenberg’s Uncertainty Principle. Heisenberg was a contemporary of Oppenheimer. He lead the Nazi’s war-effort to figure out how to split atoms and create weapons of mass destruction too.

So far, we’ve survived these earlier advances in atomic physics, which have led to the subsequent discovery of quantum mechanics. During the past decade, scientists have been researching how to apply quantum mechanics to computing. Today, quantum computing may hold one of the keys to the future’s super computers—computers that are far advanced and more powerful than anything we can conceive of today. If quantum computing is fully realized, this leap in computing power will be, well, a quantum leap.

The underlying principle of quantum computing is that the quantum properties of subatomic particles can be utilized to represent and structure data. Specially devised quantum mechanisms can then be used to perform operations and computations with that data.

Today’s conventional computers process and store information in bits, which exist in either a 1 or a 0 state. In quantum computing, however, there are qubits, which can be in both states at the same time. This “quantum parallelism” is a key to the potential power of quantum computing. Another quantum property, entanglement, is what makes it possible for a qubit to exist in both states simultaneously.

Quantum computing is difficult to comprehend, but quantum entanglement is where it gets downright weird and takes on the air of something that exists only in sci-fi movies. Entanglement is a quantum mechanical phenomenon in which two or more particles become intrinsically connected and interdependent even though they are physically separated. Two entangled qubits then would be able to communicate instantaneously with one another no matter how far apart they were. In quantum computing, data transfer rates would no longer be measured in megabits and gigabits—data transfer could occur instantly among the entangled qubits that make up quantum computers. This theoretical capability may have had something to do with Einstein labeling entanglement as “spooky action at a distance”.

Entanglement allows for another “spooky” quantum phenomenon to occur: teleportation. For me, that term instantly brings to mind visions of Star Trek with Captain Kirk and crew stepping into the teleporter to be “beamed” down to a planet. Turns out that that type of teleportation is truly science fiction while quantum teleportation remains quite real. With quantum teleportation, information about a particle’s quantum state can be “beamed” (for lack of a better word) to another particle. Note that it is not the particle itself, the physical matter, that is moved, but the information about that particle. With quantum teleportation, two entangled particles could move information, or data, between one another without a physical connection. In theory then, not only would entangled qubits in quantum computers be able to communicate instantly, they wouldn’t even need to be physically connected.

The problem with the Star Trek version of teleportation is that there would need to be an exact replica of particles already assembled on the planet below before Captain Kirk’s information, i.e., his mind, could be teleported to those particles once they’ve been entangled. Quantum teleportation then doesn’t move matter, it moves information somewhat like a fax machine doesn’t move a physical piece of paper across distance and time; rather, it moves information that is then reconstructed on a replica piece of paper.

Using quantum phenomena to perform calculations was first proposed by Richard Feynman in 1981 at a talk he gave at the First Conference on the Physics of Computation. In 1985, David Deutsch, a physicist at the University of Oxford, described the first universal quantum computer.

Thirteen years of further theorizing and experimentation passed before the first working 2-qubit computer was demonstrated at the University of California, Berkeley in 1998. While research into quantum computing has continued, the pace of advancement has been quite slow compared to ongoing advancements in conventional computing. In fact, the pace of advancement in quantum computing today looks something like the early days of conventional computing with a group of little known scientists working on something that the general public knows little to nothing about.

There is much work yet to be done and discoveries to be made before the sci-fi promise of quantum computing becomes reality. Some scientists have predicted that it will take another 20 to 30 years for the practical application of quantum computing to become fully realized—that is, if we don’t blow ourselves up with the old atomic physics first.