Quantum+Computers

 Ryan Seery and Aaron Lopes toc =__ History__= The Theory of Quantum Computing developed from the complexities of solving [|nondeterministic polynomials](decision problems). The most common decision problems are [|NP-complete]and [|NP-incomplete], which require complex algorithms to solve, if they can be solved at all! NP-incomplete problems are solved by imputting a value and solving for the unknown and from that unknown you are able to solve for other values. NP-complete problems solve algorithm(s) whose run time is polynomial allowing you to solve NP-incomplete when you change the input (NP in this case). These algorithms are extremely complex and difficult to solve. Scientists are unable to solve these algorithms using conventional bit-computers because they are unable to perform the multiple calculations at once necessary to solve the algorithm. [|Richard Feynman], and their dozens of other scientists theorized about solving NP-complete problems using faster technologies that can solve multiple polynomials. After months of thought and preparation, Feynman won the Nobel Peace Prize in 1982 for helping theorize the first mental model of the quantum computer, which uses 'qubits' to calculate unknowns within the algorithm(s) making it thousands of times faster. Since this is sill a theory, engineers remain unsure whether the future computer will be able to solve these equations. Today, there’s no functioning model of the quantum computer because physicists and chemists do not fully understand all aspects of quantum mechanics.With this said, scientists at the National Institute of Standards and Technology (NIST) in Boulder, Colorado successfully moved data from one computer chip to another using quantum technology. This implies that the understanding of quantum mechanics is growing and quantum computers will be a reality in years to come!

=__How It Works__=

//Basics//
media type="youtube" key="hSr7hyOHO1Q" width="342" height="292" align="right" Modern silicon-based computers operate using bits. These bits are a binary system, represented as ones or zeros. Since they can only be one or the other, these computers can only work on one thing at a time. Quantum computers use quantum bits, or qubits. Qubits can exist as either a one, a zero, or a superposition of one and zero, meaning one and zero at the same time. This enables them to perform multiple calculations simultaneously (theoretically, 64,000 times faster), making them many times more efficient than conventional silicon-based computers. Research on quantum computers is still theoretical. Scientists have built subpieces of a quantum computer, but a practical application is still many years and many technological advances away.

Still confused? See 'Qubits' and 'Quantum Principles' below.

Here's an example: imagine you are in a large office building. You realize you have forgotten your briefcase. It could be on a desk in any one of the many rooms in the building. If you are alone, the only way to find your briefcase would be to search every room individually until you find the right one. This is basically what normal computers do. They work with long strings of ones and zeros, one at a time. If you had colleagues with you, you could organize a search - assign one colleague per floor to search, again, individually and then regroup to compare results. Even with more people, this could take hours. Silicon-based computers are capable of doing this as well. They can split up tasks and compute parallel strings of data. This is faster than the first method, but it requires much more computing power. Now, imagine you have the capability to duplicate yourself, as many times as there are rooms in the building. Each copy searches only one room simultaneously, and once the briefcase has been found, each unsuccessful copy instantly disappears, thereby eliminating the need for communication between copies.

That's what quantum computers do. Minus the whole bit about actually duplicating yourself, of course.

//Qubits//
Qubits (pronounced like the ancient measurement, cubit) are the fundamental idea behind quantum computers. They are basically the quantum version of a conventional bit* used by modern silicon-based computers. The significant property of a qubit is its ability to represent multiple values simultaneously. This makes the computer able to employ them thousands of times more efficient that a regular computer. In fact, complicated tasks that would take the most sophisticated modern supercomputers 10 billion years to solve could be done by a quantum computer in thirty seconds.  *By the way, the word 'bit' is actually an abbreviation of 'binary digit', in the same way that 'qubit' is an abbreviation of 'quantum bit'. Just in case you were wondering.

The Bloch Sphere (left) is often used to visualize a qubit geometrically, but this page will not go into detail about the complex equations involved with it, because they would not be appropriate for a high school audience. If you would like to learn more on your own, a useful link: @http://www.quantiki.org/wiki/index.php/Bloch_sphere.

**//Problems//**
There are several problems within the quantum computer theory itself. Richard Feynman's experimental theory is based off of other uncredible theories such as superposition and entanglement which aren't fully accepted by the scientific community (Many of them believe that each theory has a different cause). This raises the question, can quantum computers really be that much better than silicon based computers? Many scientists say yes, but all of their justifications are based off of other theoretical concepts, meaning that they have no way of testing it. Therefore, the world's scientific community must fully understand quantum particles before the computer can be built and know its potential applications to say that it is truely better than today's computer.

Another problem is, if someone develops a quantum computer, what stops them from breaking almost every bank code, having access to missle fire, and controlling computer run nations? This is a problem because quantum computers theoretically have the ability to calculate multiple variables, allowing them to crack hundreds of prime digits which make up bank, defense, and traffic codes. So, if quantum computers get into the 'wrong hands', it may be catastrophic.

Quantum Computers may be extremely dangerous as well. This is because quantum computers use single particles to transfer data within a computer, and some of them may become unstable depending on their energy intake and energy release. If they become unstable, they may explode because unstable particles may react with other unstable particles, causing a violent reaction. The multitude of the explosion can vary depending on the particle's make-up, what it reacts with, the amount of energy is absorbs when reacting, etc. However, it is certain that these unstable particles may cause an explosion, or other type of reaction, so there's a risk factor when using a quantum computer.

=__Quantum Principles__= Superposition is the reason qubits can exist as multiple values at the same time. It describes all the possible states a particle can exist in. A qubit's value is represented by electrons jumping back and forth between grounded (zero) and excited (one) states. Since quantum principles apply to qubits, they can not only represent a one or zero, but all the values in between as well - simutaneously. Since superposition expresses that qubits can be multiple values, this convinces engineers that they can perform several calculations at once, making them more versital.

Quantum computers make use of a quantum principle called entanglement. One of the problems with using qubits is that when in superposition, they behave as electrons do in a wave function. Once a qubit in superposition is disturbed by an observer, it chooses a definite value (one or zero), which defeats the entire purpose of using qubits. So, if two particles are entangled, the computer can know the value of one particle by measuring the other, thereby not disturbing the first particle. Entanglement allows for both values of a qubit in superposition to be acted on at once, which is why qubits are so much more efficient than conventional bits.

Some scientists believe that it may even be possible to use a quantum principle called [|'quantum tunnelling'] to transport information instantaneously without loss of energy, and regardless of the distance. This is because the quantum tunnelling theory says that particles (at the quantum level) have a small chance of colliding and passing through nodes. An example of this is nuclear activity on the sun. Physicists know that the particles on the sun do not have enough energy to bond at the molecular level; therefore, the sun wouldn't shine. Since the sun shines, __some__ physicists explain the reaction process with quantum tunnelling because the quantum particles have a slight chance of passing through energy levels of a particle (pass through nodes) and reacting with the substance. This principle relates to quantum computers because quantum tunneling implies that quantum particles (particles that move information within the computer) have a probability of transfering through a wire, losing no energy to heat. This statement is highly debatable because it totally ignores friction as a factor, thus causing much controversy. However, if scientists can develop a way to increase this theoretical probability to 100%, they are able to develop a computer using a set amount of energy, thus making it extremely eco-friendly.

=__Practical Applications__= Engineers and scientists believe quantum computers have several applications ranging from measuring substances more accurately, to fully understanding the behavior of quantum particles. However, both engineers and scientists agree that these computers will have the capability to crack most if not all codes known to man. This is because quantum computers have the ability to calculate all prime numbers that make up codes throughout the world. This will allow them to access all bank accounts, access all power sources, control nuclear weapons, and give them the ability to conquer a technology based country. A quantum computer can calculate prime numbers making sure they have one set of factors. Since quantum computers can compute several numbers at once, they are able to find large prime numbers, by dividing them thousands of times to make sure they have one set of factors. These prime numbers make up codes which run our world, and the ability to break these codes, gives a person/group unlimited power.

Another predicted application is the computer's ability to search for multiple things at once, which will help in the formation of [|data banks]. Normally, people research individual topics and themes and contribute it to a group data base, or they do it individually. The theory of the quantum computer allows people to research multiple topics at once, allowing people to complete their database(s) faster. This is significant because websites such as Wikipeida and Iconn can be made within a matter of days instead of years, and the compaction of human intelligence will quicken a student's ability to finish a project or write a paper because the all the information is from one specific source.

However, not all problems can necessarily be done faster by a quantum computer than by a regular computer. Going back to the office building example, imagine that you have the task of finding and assembling pieces of a watch scattered randomly throughout the building. No matter how many duplicates of yourself you have, you still have to assemble the watch piece by piece, one at a time. Each step is specific and depends upon the preceding step. In essence, this makes a quantum computer no better than a silicon computer for this type of task. This theory, however, is still debatable because physicists, engineers, and chemists remain unsure of a particle's behavior at the quantum level.