Quantum computing has revolutionized the way we think of computation and information processing. Before jumping into quantum computing meaning, let us familiarize ourselves with some common terminologies. Classical computing – In classical computing, all the computations can be performed using a collection of bits. We perform gates (NAND) on these bits to construct different functions.
Quantum – Think of quantum as similar to quantity. To be specific, it means the smallest possible amount in which we can represent a physical property, for example, energy. What could be the smallest (atomic) unit of something? That’s a quantum.
Quantum computer a hypothetical machine in which all the operations like calculations are performed considering the behavior of particles at their sub-atomic level. The data units exist in more than one state at the same time, unlike the binary computers that we have now. That means the machine can perform several independent things at the same time. Such a computer will be able to complete more instructions per second. Qubit –Quantum-bit or Qubit is a bit that can take multiple values at the same time. Just like binary has 1(high) and 0(low), qubits have more states like 00, 01, 10 and 11. So, in addition to the usual gates (NAND, XOR, etc) quantum computing has a mode Q01 which is a change from the state 0 to a state of superposition of 0 and 1.
What is Quantum computing?
The classical computing model, the basic unit of computation is a bit. In contrast, quantum mechanics replace bit with the qubit. This, together with the fundamental principle of superposition leads to high-speed computation powers known as quantum computing. Information processing becomes faster and more accurate. Multiple tasks can be performed at the same time without compromising on integrity.
With quantum computing, the entire notion of computation will change and lead to faster algorithms, improved communication protocols, and better cryptographic mechanisms.
In the early 80s, a few researchers noted that quantum mechanics can be more useful for information processing. As proof, scientists showed how the nonclassical properties of quantum measurement helped in establishing a cryptographic key. They realized that this quantum phenomenon, the phenomena of entangled particles, could not be simulated using existing machines like the Turing machine.
Further, in the early 1990s, researchers developed their first set of quantum algorithms. These were superior and produced consistent results in a faster manner. Since then, quantum operations have been performed in polynomial time to produce faster results.
How does quantum computing work?
Qubits and superposition
The basic building block of quantum computing is the qubit. The number of qubits determines the number of computations that the quantum computer can do. For instance, if a particle is aligned with a field, consider it state 0 (spin-up state), and if it is opposite, let the state be 1 (spin down). The change in this state can be caused by an energy pulse. Further, if we use only a part of the energy pulse and remove the external factors influencing the particle, the particle enters a superposition state. This means neither 0 nor 1, but in both states at the same time. Seems like, such a particle can be then utilized to perform 2^n calculations where n = number of qubits.
When particles interact with each other (electrons, qubits or photons), they can be entangled with each other and form pairs. This process is called correlation.
With the knowledge of the spin state of one particle, we can know that the other particle of the pair is spinning in the opposite direction. If one electron is in the spin-up state, the other will be in a spin-down state. Next, we apply superposition. We can find that the particle is simultaneously in spin-up and spin-down states when isolated. The exact state can be only known at the time of measurement. Therefore, as long as each particle (like qubit) is isolated, even if there is more distance between them, the particles can be correlated.
Both superposition and entanglement can together create great computing powers allowing future developers to write computer programs in a totally new way.
The applications of Quantum computing like more specific algorithms for AI, statistical analysis, solving theoretical physics problems, breaking ciphers, biomedical simulations and complex financial modeling will set us into a new quantum era, with better living conditions and more efficient technological advancements.
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