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What Is a Quantum Computer ?
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- A quantum computer is a machine that performs calculations based on the laws of quantum mechanics, which is the behavior of particles at the sub-atomic level

- Computer technology is making devices smaller and smaller. We are reaching a point where classical physics is no longer a suitable model for the laws of physics

- The Turing machine, developed by Alan Turing in the 1930s, is a theoretical device that consists of tape of unlimited length that is divided into little squares. Well in a quantum Turing machine, the difference is that the tape exists in a quantum state, as does the read-write head.

- What this means is that the symbols on the tape can be either 0 or 1 or a superposition of 0 and 1. In other words the symbols are both 0 and 1 at the same time. While a normal Turing machine can only perform one calculation at a time, a Quantum Turing machine can perform many calculations at once.

- Today's computers, like a Turing machine, work by manipulating bits that exist in one of two states: a 0 or a 1. Quantum computers arent limited to two states; they encode information as quantum bits, or qubits, which can exist in superposition.

- Qubits represent atoms, ions, photons or electrons and their respective control devices that are working together to act as a computer memory and a processor. Since a quantum computer can contain these multiple states simultaneously, it has the potential to be millions of times more powerful than todays most powerful supercomputers.

The superposition of qubits is what gives Quantum computers their inherent parallelism. According to physicists, this parallelism allows a quantum computer to work on a million computations at once, while your desktop pc works on one.

- A 30-qubit-quantum computer would equal the processing power of a conventional computer that could run teraflops (trillions of floating-point operations per second). Todays typical desktop computers run at speeds measured in gigaflops (billions of floating-point operations).

- Quantum computers also utilize another aspect of quantum mechanics known as entanglement. One problem with the idea of quantum computers is that if you look at subatomic particles, you could bump them, and thereby change their value

- Entanglement provides a potential answer. In quantum physics, if you apply an outside force to two atoms, it can cause them to become entangled, and the second atom can take on the properties of the first atom

- If left alone, an atom will spin in all directions. The instance when it is disturbed it chooses one spin, or one value; and at the same time; the second entangled atom will choose an opposite spin, or value

- This will allow scientist to know the value of the qubits without actually looking at them

- Quantum computers could one day replace silicon chips, just like the transistor once replaced the vacuum tube. But for now, the technology required to develop a every day quantum computer is beyond our reach and financial reach

- Most research in quantum computing is still very theoretical

- The most advanced quantum computers have not gone beyond manipulating more than several qubits, meaning that they are a far cry from practical applications

- If functional quantum computers can be built, they will be valuable in factoring large numbers, and therefore extremely useful for decoding and encoding secret information

- If one were to be built today, no information on the Internet would be safe. Our current methods of encryption are simple compared to the complicated methods possible in quantum computers

- Quantum computers could also be used to search large databases in a fraction of the time that it would take a conventional computer

- Other applications could include using quantum computers to study quantum mechanics, or even to design other quantum computers

- However quantum computing is still in its early stages of development, and many computer scientists believe the technology needed to create a practical quantum computer is years away

- Quantum computers must have at least several dozen qubits to be able to solve real-world problems, and thus serve as a viable computing method

- The single-atom transistor could lead the to building a quantum computer that works by controlling the electrons and thereby the quantum information, or qubits

- However the single-atom transistor does have one serious current limitation:

-----> It must be kept cold, at least as cold as liquid nitrogen, or minus 391 degrees Fahrenheit(minus 196 Celsius)