### What is quantum computing and do quantum computers exist?

## Introduction

Once again, the vision of superfast and strong quantum computers was brought into view, and vast funds were spent in science in Sweden, Europe, and the world. While there are no practical algorithms available for quantum computers, the technology is supposed to be enormously important in simulating biological, chemical and physical structures that are far too complex even for the most powerful computers currently available. A bit in a digital device can only take one or zero value, but a quantum bit will take all the intermediate values as well. In simple terms, it implies that for each computation they do, quantum computers do not need to perform as many operations as ordinary computers. Quantum computers are going to solve a question that is too complex for a traditional machine to take on or at least that’s what they are expected to do. Scientists and companies are now rushing toward this milestone in computation called Quantum supremacy and apparently just beyond our grasp.

## Quantum Computing

Quantum computing is the field that deals with using principles of quantum theory for developing computer technology. If feasible, the design of a quantum computer will mark a step forward in computational power much greater than from abacus to a contemporary supercomputer, with the performance gain in the range of multi-billion range and beyond. According to the principles of quantum physics, the quantum computer will achieve tremendous processing power by being able to be in multiple states and perform concurrent tasks using all possible permutations. MIT, IBM, Oxford University and Los Alamos National Laboratory are currently leading centers of quantum computing.

The development of Quantum Theory began in 1900 with Max Planck’s presentation to the German Physical Society, in which he introduced a revolutionary idea that radiational energy is emitted or absorbed not continuously but discontinuously in the form of small packets of energy called quanta. Over the next thirty years, further developments by several scientists led to the modern understanding of quantum theory.

Quantum Theory’s Fundamental Elements are the followings:

- Energy like matter, consists of discrete units, not just as a continuous wave
- Depending on the conditions, basic units of both energy and matter behave as particles or waves,
- The movement of elementary particles is inherently random and therefore unpredictable.
- The simultaneous calculation of two opposite values, such as the position and momentum of the elementary particle, is ultimately inaccurate; the more reliably one value is measured, the less reliable the other value is measured.

Quantum computing takes advantage of subatomic particles’ peculiar potential to exist in more than one state at any moment. Operations can be done much faster and with less energy consumption than conventional computers because of the way the tiniest of particles behave. In classical digital computation, a bit is a single piece of information that can exist in only two states–1 and 0. Quantum computing uses quantum Bits or Qubits. These are two-state quantum systems. Unlike a standard bit, they can store much more data than just 0 or 1, because they can exist in any overlay of these values.

Representation of Bits and Qubits

The distinction between classical Bits and Qubits is that in a quantum superposition of 0 and 1 we can also prepare Qubits and create nontrivial entangled states of several Qubits, so-called entangled states. A Qubit can be viewed as an intangible sphere while a classical bit can be any point on the sphere in two states, i.e., at either of the two poles of the sphere. It means that a machine that uses such parts can contain a vast amount of information and consumes less power than a traditional computer.

## Do quantum computers exist?

Indeed, in many labs around the world, there are simple quantum computers. Companies such as Microsoft, IBM and Google are all developing their own, the US and Chinese governments, as well as the EU, are all investing in it. It should be mentioned that with only a small number of Qubits, these prototypes are all very simple and not capable enough to solve any practical problems.

Quantum computers make calculations based on the likelihood of the state of an object before it is calculated-rather than just 1s or 0s and this ensures that they have the capacity to handle more information indefinitely compared to conventional computers. Classical computers use the definite position of a physical state to perform logical operations. Usually, these are binary, meaning that their operations are based on one of two positions. A single state is called a bit, like on or off, up or down, 1 or 0. A computer with N bits can then be in 2^N states.

In quantum computing, operations are based on an object’s quantum state to generate what is Qubit. Such states are an object’s unknown properties prior to their observation, such as an electron’s spin or a photon’s polarization. Unmeasured quantum states occur in a superposition of states rather than having a clear position. Observing or controlling such superpositions, however, can be quite complicated. If one can make a system that can maintain bits in a superposition of the possible states for a long time, then it would be possible to simultaneously do a lot of computations that would be otherwise lengthy and time-consuming.

The complex mathematics behind these unsettled states of entangled ‘spinning coins’ can be plugged into special algorithms to make short work on issues that would take a long time for a conventional computer to work out how they could ever be calculated. Such algorithms would help to solve complex mathematical problems, create hard-to-break security codes or predict multiple particle interactions in chemical reactions

Creating a practical quantum computer demands that an object be kept in a state of superposition long enough to perform different operations on it. Sadly, once a superposition encounters materials that are part of a calculated process, in what is known as decoherence, it loses its intermediate state and becomes a boring old classical piece. Devices need to be able to shield from decoherence quantum states while still making them easy to interpret. Various methods approach this problem from different angles, whether using more efficient quantum processes or finding better ways to search for errors

## Wrap up

Classical technology can do any task on a quantum computer for the time being. Quantum dominance defines a quantum computer’s ability to outperform its classic predecessors. Many firms, including IBM and Google, suggest that we might be near because we keep cramming together more Qubits and creating more reliable tools. Not everyone is persuaded that the effort is worth the number of machines. Some mathematicians believe that there are barriers that are virtually impossible to overcome, making quantum computing out of reach forever. Time is going to say who’s wrong.