A Quantum Computer - a Future Technology

By the strange laws of quantum mechanics, Folger, a senior editor at Discover, notes, an electron, proton, or other subatomic particle is \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\"in more than one place at a time,\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\" because individual particles behave like waves, these different places are different states that an atom can exist in simultaneously. Ten years ago, Folger writes, David Deutsch, a physicist at Oxford University, argued that it may be possible to build an extremely

powerful computer based on this peculiar reality. In 1994, Peter Shor, a mathematician at AT&T Bell Laboratories in New Jersey, proved that, in theory at least, a full-blown quantum computer could factor even the largest numbers in seconds--an accomplishment impossible for even the fastest conventional computer.

An outbreak of theories and discussions of the possibility

of buildig a quantum computer now permeates itself thoughtout the quantum fields of technology and research. It\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'s roots can be traced back to 1981, when Richard Feynman noted that physicists always seem to run into computational problems when they try to simulate a system in which quantum mechanics would take place. The caluclations involving the behavior of atoms, electrons, or photons, require an immense amount of time on today\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'s computers. In 1985 in Oxford England the first description of how a quantum computer might work surfaced with David Deutsch\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'s theories. The new device would not only be able to surpass today\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'s computers in speed, but also could perform some logical operations that conventional ones couldn\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'t.

This research

began looking into actually constructing a device and with the go ahead and additional funding of AT&T Bell Laboratories in Murray Hill, New Jersey a new member of the team was added. Peter Shor made the discovery that quantum computation can greatly speed factoring of whole numbers. It\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'s more than just a step in micro-computing technology, it could offer insights into real world applications such as cryptography. \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\"There is a hope at the end of the tunnel that quantum computers may one day become a reality,\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\" says Gilles Brassard of University of Montreal.

Quantum Mechanics give an unexpected clarity in the description of the behavior of atoms, electrons, and photons on the microscopic levels. Although this information isn\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'t applicable in everday household uses it does certainly apply to every interaction of matter that we can see, the real benefits of this knowledge are just beginning to show themselves. In our computers, circuit

boards are designed so that a 1 or a 0 is represented by differering amounts of electriciy, the outcome of one possibility

has no effect on the other. However, a problem arises when quantum theories are introduced, the outcomes come from a single piece of hardware existing in two separate

realities and these realites overlap one another affecting both outcomes at once. These problems can become one of the greatest strengths

of the new computer however, if it is possible to program the outcomes in such a way so that undesirable effects cancel themselves out while the positive ones reinforce each other. This quantum system must be able to program the equation into it, verify it\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'s computation, and extract the results.

Several possible systems have been looked at by researchers, one of which involves using electrons, atoms, or ions trapped inside of magnetic fields, intersecting lasers would then be used to excite the confined particles to the right wavelength and a second time to restore the particles to their ground state. A sequence of pulses could be used to array the particles into a pattern usuable in our system of equations. Another possibility by Seth Lloyd of MIT proposed using organic-metallic polymers (one dimensional molecules made of repeating atoms). The energy states of a given atom would be determined by it\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'s interation with neighboring atoms in the chain. Laser pulses could be used to send signals down the polymer chain and the two ends would create two unique energy states. A third

proposal was to replace the organic molecules with crystals in which information would be stored in the crystals in specific frequencies that could be processed with additional

pulses.

The atomic nuclei, spining in either of two states (clockwise or counterclockwise) could be programmed with a tip of a atomic microscope, either \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\"reading\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\" it\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'s surface or altering it, which of course would be \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\"writing\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\" part of information storage. \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\"Repetitive motions of the tip, you could eventually write out any desired logic circuit

, \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\" DiVincenzo said. This power comes at a price however, in that these states would have to remain completely isolated from everything, including a stray photon. These outside influences would accumulate, causing the system to wander off track and it could even turn around and end up going backward causing frequent mistakes.

To keep this from forming new theories have arisen to overcome this. One way is to keep the computations relatively short to reduce chances of error, another would