Quantum Computing (Part-II)- Fundamentals of Quantum Computing

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Introduction to the Fundamentals of Quantum Computing and Details about the Programming Methodology done in D-Wave Systems 

Now we continue with the second part of our blog on quantum computing. Those who have missed our first blog can read it from Here. It will help to connect with this second part of the blog discussing fundamentals of quantum computing  and programming methodology done in D-wave systems.

Fundamentals of Quantum Computing

Instead of saving information using bits represented by 0s or 1s as traditional digital computers do, quantum computers use the technique of  quantum bits, or qubits, to encode information as 0s, 1s, or both at the same moment. This superposition of states—along with the other quantum mechanical methodology of entanglement and tunneling—enables quantum computers to calculate and analyse huge coalescence of states at once. A Hellenic computer has a memory build-up of bits, where each and every bit is characterized by either a one or a zero. A quantum computer, on the other hand, cultivate a sequence of qubits, which can characterize a one, a zero, or any quantum superposition of those two qubit states;[10]:13–16 a pair of qubits can be in any quantum superposition of 4 states,[10]:16 and three qubits in any superposition of 8 states. In general, a quantum computer with {\displaystyle n} n qubits can be in an capricious superposition of up to {\displaystyle 2^{n}} 2^{n} different states simultaneously[10]:17. (This compares to a normal computer that can only be in one of these {\displaystyle 2^{n}} 2^{n} states at any one time). A quantum computer conduct on its qubits using quantum gates and measurement (which also alters the observed state). An algorithm is repressed of a fixed arrangement of quantum logic gates and a problem is encoded by mounting the initial values of the qubits, equivalent to how a Hellenic computer works. The computation usually ends with a measurement, collapsing the system of qubits into one of the {\displaystyle 2^{n}} 2^{n} eigenstates, where each qubit is zero or one, decomposing into a classical state. The result can therefore be at most {\displaystyle n} n classical bits of information (or, if the algorithm did not end with a measurement, the result is an unobserved quantum state).Quantum algorithms are often probabilistic, in that they provide the correct solution only with a certain known probability. Note that the term non-deterministic computing must not be used in that case to mean probabilistic (computing), because the term non-deterministic has some other meaning in computer science. An example of an implementation of qubits of a quantum computer could start with the use of particles with two spin states: "down" and "up" (typically written {\displaystyle |{\downarrow }\rangle } |{\downarrow }\rangle  and {\displaystyle |{\uparrow }\rangle } |{\uparrow }\rangle , or {\displaystyle |0{\rangle }} |0{\rangle } and {\displaystyle |1{\rangle }} |1{\rangle }). This is true because any such system can be mapped onto an effective spin-1/2 system.

How the Programming is done in D-Wave System?

The D-Wave system uses a web application program interface with client libraries available for C/C++, Python, and MATLAB. This permits users to use the computer easily and readily as a cloud resource across a network. To program the system, a user targets and maps a problem into a search for the “lowest point in a vast landscape,” and that is equivalent to the best possible result. The quantum processing unit considers all the possibilities together to arbitrate the lowest energy required to form those relationships. The solutions are values that equivalent to the optimal configurations of qubits found, or the lowest points in the energy landscape. These values are returned to the user program over the network. Because a quantum computer is probabilistic rather than deterministic, the computer returns many very good answers in a short amount of time. This gives not only the best solution found but also best alternatives from which to choose. D-Wave systems are contracted to be used to complement classical computers. There are many examples of problems where a quantum computer can complement an HPC (high-performance computing) system. While the quantum computer is well suited to discrete optimization, for example, the HPC system is better at large-scale numerical simulations.

To be continued in the next blog...