quantum computing
Imagine a computer whose memory is exponentially larger than its apparent physical size; a computer that can manipulate an exponential set of inputs simultaneously; a computer that computes in the twilight zone of space. You would be thinking of a quantum computer. Relatively few and simple concepts of quantum mechanics are needed for quantum computers to be a possibility. The subtlety has been in learning to manipulate these concepts. Is such a computer an inevitability or will it be too difficult to build?
Because of the strange laws of quantum mechanics, Folger, a senior editor at Discover, points out that; 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 in which an atom can exist simultaneously.
What is the problem with quantum computing? Imagine that you are in a large office building and you have to recover a briefcase that was left on a randomly chosen desk in one of hundreds of offices. In the same way that you would have to walk through the building, opening the doors one at a time to find the briefcase, an ordinary computer has to go through long strings of 1’s and 0’s to get to the answer. But what if instead of having to search for yourself, you could instantly create as many copies of yourself as there are rooms in the building? All the copies could watch simultaneously in all the offices, and whoever finds the briefcase becomes the real you. the rest just disappear. – (David Freeman, discover)
David Deutsch, a physicist at the University of Oxford, argued that it is 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, showed that, in theory at least, a full-fledged quantum computer could factor even the largest numbers in seconds; an impossible achievement for even the fastest conventional computer. A burst of theories and discussions about the possibility of building a quantum computer now pervades the quantum fields of technology and research.
Its roots go back to 1981, when Richard Feynman pointed out that physicists always seem to run into computational problems when trying to simulate a system in which quantum mechanics would take place. Calculations 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 could work with the theories of David Deutsch appeared. The new device would not only be able to outperform current computers, but would also be able to perform some logical operations that conventional ones couldn’t.
This research began by looking to actually build a device, and with the go-ahead and additional funding from AT&T Bell Laboratories in Murray Hill, New Jersey, a new member was added to the team. Peter Shor made the discovery that quantum computing can greatly speed up the factorization of integers. It is more than just a step in microcomputing technology, it could offer insights into real-world applications such as cryptography.
“There is hope at the end of the tunnel that quantum computers will one day become a reality,” says Gilles Brassard of the University of Montreal. Quantum Mechanics provides unexpected clarity in describing the behavior of atoms, electrons, and photons at microscopic levels. Although this information is not applicable in everyday home uses, it certainly applies to every interaction of matter that we can see, the real benefits of this knowledge are just beginning to show.
In our computers, the circuit boards are designed so that a 1 or a 0 is represented by different amounts of electricity, the outcome of one possibility having no effect on the other. However, a problem arises when quantum theories are introduced, the results come from a single piece of hardware that exists in two separate realities and these realities overlap each other and affect both results at once. However, these problems may become one of the new computer’s greatest strengths, if the results can be programmed in such a way that the undesirable effects cancel out while the positive ones reinforce each other.
This quantum system must be able to program the equation into it, verify its calculation, and extract the results. The researchers have looked at several possible systems, one of which involves using electrons, atoms or ions trapped within magnetic fields, intersecting lasers would be used to excite the confined particles to the correct wavelength and a second time to restore the particles. to its ground state. A sequence of pulses could be used to order the particles into a pattern usable in our system of equations.
Another from Seth Lloyd of MIT proposed using organic-metallic polymers (one-dimensional molecules made of atoms of repeating possibilities). The energy states of a given atom would be determined by its interaction with neighboring atoms in the chain. Laser pulses could be used to send signals down the polymer chain, with the two ends creating two unique energy states.
A third proposal was to replace organic molecules with crystals in which information would be stored in the crystals at specific frequencies that could be processed with additional pulses. Atomic nuclei, spinning in either of two states (clockwise or counterclockwise) could be programmed with the tip of an atomic microscope, either by “reading” their surface or by altering it. , which of course would be “writing” part of the information storage. “Repetitive movements of the tip, you could eventually write any desired logic circuit,” DiVincenzo said.
However, this power comes at a price, as these states would have to remain completely isolated from everything, including a stray photon. These outside influences would build up, causing the system to go off track and could even turn around and end up rolling back causing frequent errors. To prevent this from forming, new theories have emerged to overcome this. One way is to keep the computations relatively short to reduce the chance of error, another would be to restore redundant copies of the data on separate machines and take the average (mode) of the responses.
This would no doubt forgo any quantum computer advantage, so AT&T Bell Laboratories has invented an error correction method in which the quantum bit of data would be encoded into one of nine quantum bits. If one of the nine were lost, then it would be possible to recover the data of the information that passed. This would be the protected position that the quantum state would enter before being transmitted. Also, since the states of atoms exist in two states, if one were to become corrupted, the state of the atom could be determined simply by looking at the opposite end of the atom, since each side contains exactly the opposite polarity.
The gates that would transmit the information is what researchers are primarily focused on today, this single quantum logic gate and its arrangement of components to perform a particular operation. One of those gates could control the change from 1 to 0 and vice versa, while another could take two bits and output 0 if they are both the same, 1 if they are different.
These gates would be rows of ions held in a magnetic trap or individual atoms passing through microwave cavities. This single gate could be built within a year or two, but a logical computer must have the millions of gates to be practical. NYU’s Tycho Sleator and UIA’s Harald Weinfurter see quantum logic gates as simple steps to making a quantum logic network.
These networks would be nothing more than rows of doors that interact with each other. Laser beams shining on the ions cause a transition from one quantum state to another that can alter the type of collective motion possible in the array, and thus specific light frequencies could be used to control the interactions between the ions. One name given to these arrays has been called “quantum dot arrays” in the sense that individual electrons would be confined to the quantum dot structures, encoding information to perform mathematical operations from simple addition to factorization of those integers.
“Quantum dot” structures would build on advances in the fabrication of microscopic semiconductor boxes, whose walls keep electrons confined to the small region of the material, another way to control how information is processed. Craig Lent, the project’s principal investigator, bases this on a unit consisting of five quantum dots, one in the center and four at the ends of a square, electrons would funnel between any two sites.
Linking them together would create the logic circuits that the new quantum computer would require. The distance would be enough to create “binary wires” made of rows of these units, changing state at one end causing a chain reaction to flip all states of the units along the wire, much like today’s dominoes. They transmit inertia. Speculation about the impact of such technology has been debated and dreamed about for years.
In the discussion points, the point that its potential harm could be that computational speed could thwart any security attempts, especially the NSA’s data encryption standard would now be useless as the algorithm would be a trivial problem for such a machine. . In the last part, this dream reality first appeared on the television show Quantum Leap, where this technology becomes apparent when Ziggy, the parallel hybrid computer he has designed and programmed, is mentioned the capabilities of a mirror quantum computer that of the program’s hybrid computer.