What are Quantum Computers?

Quantum computer technology involves the use of the quantum particle as a replacement for the bit of today's computers. The theory for quantum computers began over 20 years ago with Paul Benioff, a physicist at the Argonne National Laboratory, who used the concept of the Turing machine as a model for the quantum computer. A Turing machine is composed of a tape of indefinite length that can be divided into evenly sized squares. A device capable of reading the blanks and symbols in the tape is used to give instructions to a machine so that a particular program can be performed.

Theory Underlying Quantum Computers

The quantum computer uses quantum particles as the "tape" in the Turing experiment. Because the presence of a symbol or a blank in the Turing tape symbolizes the binary digits, so can the state of the quantum particles be used to hold these values. The use of multiple quantum particles also means that the quantum computer will be much faster than the Turing machine since it can perform several calculations simultaneously.

Moreover, unlike today's computers that uses the basic bit which has only two states (1 or 0), a quantum computer will store information as quantum bits which can hold more than two values. This ability of qubits to exist in more than two states means that a quantum computer has the capability of performing more than a million simultaneous computations at one time and the potential to be a lot faster and a lot more powerful than today's supercomputers.

Quantum computers will also be able to utilize one other important characteristic of quantum particles known as entanglement. The property of entanglement makes it possible to assign and determine the value or the spin of a quantum particle by introducing an outside force.

Development of Quantum Computers

Although the quantum particle can be utilized to make computers, quantum computers are still far from becoming a reality and most of the research about them is theoretical. To date, researchers haven't been able to manipulate more than 7 qubits in solving mathematical equations. There had been developments in this field, however, and the most remarkable of them are:

An experiment on August 2000 by researchers at IBM

Almaden center for research was able to make the nuclei of five fluorine atoms interact as qubits using magnetic resonance imaging and radio frequency pulses. This experiment proved successful in solving a complex mathematical problem called order finding (determining the period of a function) in one step. Today's computers are able to solve the same problem only through repeated cycles.

Same year experiment at Los Alamos National Laboratory

Researchers were able to develop a 7-qubit quantum computer that utilizes NMR to influence particles in the nuclei of molecules in a trans crotonic fluid (fluid made up of four carbon atoms and 6 hydrogen atoms). The NMR was used to line up the particles though the application of electromagnetic pulses mimicking the bit information encoding process of digital computers.