Quantum Computers: The next-generation super computers
Quantum computers are the most advanced form of computers. Unlike traditional computers, they make use of quantum mechanics theory. They are the next-generation super computers. Read this article to know more about quantum computers.
Quantum computers are quite different from traditional computers. Quantum computers make use of quantum mechanics theory and their architecture, functional units and mechanisms are ultra-modern. For understanding what a quantum computer is, we should first understand what quantum mechanics is.
A quantum computer follows quantum phenomena like superposition and entanglement for data operations. Quantum mechanics, also known as quantum physics, is a branch of science (of physics to be precise) which deals with physical phenomena at microscopic level. Quantum superposition is the fundamental principle of quantum mechanics. It says that the original state of a quantum particle must be regarded as the result of a kind of superposition of two or more new states. The state of a microscopic particle (like electrons and protons) of a physical system is its state of existence in a quantum system. This is shown as a vector in vector space. Finally, Quantum entanglement is a form of quantum superposition. That's all about quantum mechanics.
To study quantum computers, let's understand their hardware and software. Hardware of quantum computers :
The fundamental units of these systems are quantum bits or simply qubits. Just like bits in traditional computers, quantum bits are the basic units of information. A qubit is a two-state quantum mechanical system. There are horizontal and vertical polarizations. Thus, a single qubit represents 1, 0 or any other quantum superposition of two qubit states represented by nanoscale physical properties like nuclear spins described by probability amplitudes. These states may be inter-related in such a manner that a single logic gate acts on all possible states.
Qubits are implemented by the polarization states of a photon or by the spin of a single atom. These qubits are sequentially processed by quantum logic gates. A quantum gate / quantum logic gate is a basic quantum circuit operating on a small number of qubits. The sequence in which gates are applied is called quantum algorithm. The calculations are done by measuring all states and then decomposing each qubit into one of the two pure states. Quantum logic gates are represented by unitary matrices. In mathematics, a complex square matrix U is unitary if U*U=UU*=I, where I is the identity matrix and U* is the conjugate transpose of U. A single cell consists of 8-qubits. A combination of these cells forms quantum chips or quantum processors.
Software of quantum computers :
The Coded Quantum Programming software is used in quantum computers. The software uses a set of programming languages like Quantum Programming Language (QPL), Quantum Pseudo Code and Quantum Computing Language (QCL) which express quantum algorithms in high-level constructs. The software programs for computing performance and speed (like Travelling Salesman Problem) are coded to compare their performance levels with traditional computers. Catherine McGeoch, a professor of computer science at Amherst College recently conducted a quantum versus traditional computer test. McGeoch chose D-Wave's Vesuvius Prototype for analysis. D-Wave's Vesuvius Prototype is the world's first commercially available quantum computer. In McGeoch speed test, it was found that the traditional chip took thirty minutes to solve the Travelling Salesman Problem while the Vesuvius completed the same task in less than half a second. The Travelling Salesman Problem (TSP) is: "Given a list of cities and the distances between each pair of cities, what is the shortest possible route so that the sales man visits each city exactly once and returns to the origin city?" Advantages of quantum computers :
Disadvantages of quantum computers :
Conclusion :
Quantum computers are the next generation super computers. They can perform complex engineering, mathematical and biological computations in much less time. Due to certain disadvantages and high price, quantum computers may not currently replace the traditional computers. After the ongoing researches and developments in the field, we may soon get handy quantum computers.
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