What is Quantum Computing? (Explained)

What is Quantum Computing?

Quantum computing is a process that uses a machine that is designed on the basis of quantum mechanical phenomena. These machines perform the necessary calculations on data on the basis of superposition and entanglement.

Technically, these devices are different from a traditional digital computer in their design. These computers use quantum bits and subatomic particles which make them function several times faster than any traditional computer.


  • Quantum computing is a specific area of computer science which uses the principles of quantum theory involving the behavior of matter and energy both at the atomic as well as at the subatomic level.
  • It is the process that allows solving complex problems most easily using powerful yet elegant machines that are smaller and consume less energy than the supercomputers.
  • Unlike classical computing, quantum computing uses qubits in a multidimensional state rather than 0 or 1, where more of them increase the power of the computers.
  • This type of computing offers several benefits apart from solving complex problems fast, which is why it has larger and wider use cases and applications.
  • Quantum computing is very much a reality but to be adopted in the large scale is a matter of time and subject to doing away with its limitations.

Understanding Quantum Computing

What is Quantum Computing

Typically, quantum computing is based on subatomic particles such as electrons and photons.

Quantum computing is a fast-changing technology and uses the laws of quantum mechanics.

This type of computing solves problems that may be too complex for a standard computer to solve in quick time.

In short, quantum computing can solve problems that even supercomputers fail at.

While the traditional computers use electronic circuits on a semiconductor plate made of silicon and represent bits or binary digits in the state of either 0 or 1, a quantum computer, in contrast, uses quantum bits, which are commonly known as qubits.

The quantum bits allow the subatomic particles to exist at the same time in more than one state, 1 and 0.

Theoretically, when the qubits are linked, it can use the interference between the quantum states, which are like waves.

This helps the computer to perform large and complex calculations very quickly that may take a very long time when computed otherwise.

These qubits also represent a superposition, which involves both 1 and 0 simultaneously, and help in running most complex and multidimensional quantum algorithms.

Ideally, in quantum computing, a new approach is followed to solve these algorithms and complex problems.

They can create multidimensional spaces and patterns that link individual data points.

The machines engaged in quantum computing work with quantum processors that need to be super-cool at about a hundredth of a degree above absolute zero. That is why super-cool superfluid is used to make the superconductors.

This helps the electrons to move through these superconductors with little or no resistance and match up to form Cooper pairs.

These pairs carry charges across the insulators and barriers by a process known as quantum tunneling.

Specific junctions, such as Josephson junctions, are used as superconducting qubits to control their behavior when microwave photons are fired at them.

It also helps in holding, changing, and reading out each unit of quantum information.

These junctions are created by placing two superconductors on either side of the insulator.

The qubit itself is not very useful in quantum computing but it plays an important trick by placing the quantum information that it holds into a superposition state.

This embodies all possible combinations of configurations of the qubit.

This creates a multidimensional and complex computational space where complicated problems can be represented in newer and better ways.

Entanglement is a unique mechanical effect of quantum computing.

It compares the behavior of two qubits and changes one of them directly to have an impact on the other.

Solutions to the complex problems are found out by the quantum algorithms by leveraging these relationships.

Quantum Computing Applications

Quantum computing is used in a wide range of fields such as finance, security, aerospace designing, finance, drug development and discovery, military affairs and intelligence, nuclear fusion and other utilities, Artificial Intelligence and Machine Learning, polymer design, digital manufacturing, and Big Data search.

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Ideally, quantum computing contributes greatly with its high-speed processing and performance benefits, which allow it to be used in:

  • Improved and secure sharing of information
  • Radars to detect aircraft and missiles
  • Environment management
  • Water cleaning with chemical sensors
  • Financial institutions for designing more efficient and productive investment portfolios
  • Creating better fraud detection and trading simulators
  • Healthcare industry for offering genetically targeted medical care
  • More sophisticated DNA research
  • Online security to detect intruders in a system using light signals
  • Data encryption
  • More efficient and safer traffic planning and control systems
  • Better batteries
  • Solar capture
  • Cleaner fertilization
  • Electronic materials discovery

This efficient and fast computing practice has also found a place to secure the future of the electric vehicles as well as in systems solving complex energy issues.

In addition to that, cosmic mysteries are solved by CERN, or the European Council for Nuclear Research, with the use of quantum computers that are efficient at doing such types of complicated computing tasks.

Is Quantum Computing Really Possible?

The answer to this question is both yes and no, and everything in between. Yes, there are functional quantum computers that can do a lot of tasks, but these are more of a conceptual reality and far from becoming a commonly used, fully operational model.

It is hard to achieve the benefits offered by quantum computing and make it really useful because it is not the hardware development alone that will facilitate it.

It will also need more advanced software that should be available abundantly and easily to be used in quantum computers.

Apart from that, newer methods are also required to suppress errors and increase speed. However, the most important aspect is to orchestrate classical and quantum resources.

It is for these specific needs that the experts think that it will take a very long time for quantum computing to replace classical computing in the real world, despite the tremendous potential of this technology, especially in extremely specialized fields.

Other significant concerns related to this form of computing are:

  • Its operation at a degree tad more than absolute zero
  • Complex and intricate logistics and
  • High cost.

Therefore, real as it is, the future of quantum computing is likely to be a kind of third arm of computing power, forming a structure as follows:

  • Classical desktop computers being used for everyday life
  • Classical supercomputers being used on a broad scale and
  • Quantum computers used for specialized research in the fields of science, meteorology and pharmacology.

Most importantly, the capabilities of this type of computing will offer benefits that are likely to be much, much more than the needs of the typical business world.

All these add up to a very high extent than any average can pay or is willing to pay.

What is Quantum Computing in AI?

Quantum Computer in AI or Artificial Intelligence is a powerful and developing technological solution that is driven by the principles of quantum science. The abilities and benefits of it are poised to revolutionize several fields and industries.

Industry experts think that when AI computing can offer fault-tolerant, powerful and error-corrected computation, there will be no need for any human intelligence or interference anymore.

This form of computing would provide natural benefits over classical computing and would help in a wide range of complex and varied computing, which includes, but is not limited to:

  • Decision making
  • Visual perception
  • Speech recognition
  • Language translation
  • Financial analysis and more.

Quantum computing in AI will be able to make complex calculations fast by using the theory of quantum mechanics, using much less power in comparison to a classical computer engaged in similar tasks.

It will be much more sustainable and environmentally friendly as well.

No doubt, leading companies are using this form of computing in the manufacturing of their products or their working processes, and things have already started to heat up.

Some of the most prominent names that use quantum computing in AI and quantum algorithms include, but are not limited to:

  • Google Quantum AI that helps in leveraging the vast resources of Google and build hybrid classical-quantum models
  • Sandbox AQ that helps in the fields of financial services, health, life science, cybersecurity, material sciences, and several other public sectors
  • Quantinuum that helps in quantum machine learning and Natural Language Processing or NLP
  • Xanadu that creates quantum devices accessible to all through the cloud and helps in developing machine learning and divergent quantum circuits
  • QuLabs that build APIs, AI and quantum tools to use in different applications and leverage classical-quantum algorithms
  • Terra Quantum, which designed a neural network architecture that uses laser interferometry to help in learning algorithms.
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You may have already experienced the presence of quantum computing in AI in your home, office and other places in different forms, such as Siri and Alexa which are known for their voice-controlled operations.

Then there are those autonomous driving systems, such as the automated drones or automatic pilot of Tesla.

What are the Main Components of Quantum Computing?

The main components of quantum computing are the quantum data plane, the control and measurement planes, the control processor plane and the host processor, and qubit technologies.

Quantum data plane:

This is the core of quantum computing, which includes the structures needed to hold the physical qubits in place and a support circuitry to perform gate operations and measure the state of qubits.

This data plane needs specific technological control externally, by the separate control and measurement layer.

Control and measurement planes:

This controls the digital signals of the processor, which indicate the type of quantum operations to be carried out of the analog control signals that are needed to work on the qubits in the quantum data plane.

It also changes the measurements of the analog output of qubits to classical binary data handled by the control processor in a particular data plane.

Control processor plane and host processor:

The control processor plane detects and triggers the appropriate sequence of gate operations and measurements.

These are then carried out by the control and measurement planes on the quantum data plane to execute a program supplied by the host processor. This helps in implementing a quantum algorithm.

While the control processor plane functions at a low abstraction level while converting the codes compiled into commands for the control and measurement layers.

The user therefore does not have to interact directly with the control processor but rather with the host computer.

This host processor runs a traditional operating system to operate and uses typical supporting libraries and software development tools.

Qubit technologies:

This is the technology on which quantum computing is based. It uses trapped atomic ions that enable the processors to implement a wide array of simple quantum algorithms.

The ions here act as qubits and the trap holds them in particular locations.

The control and measurement plane has a very precise microwave or laser source that is directed at a particular ion. This affects the quantum state of the ion.

There is another laser that ‘cools’ the ions and a set of photon detectors that measure the photons scattered to find out the state of the ions.

Which Language is Used in Quantum Computing?

Typically, there are two primary groups of programming languages used in quantum computing. These are imperative quantum programming languages and functional quantum programming languages.

Each of these two groups contains different types of languages that serve different purposes.

The group of imperative quantum programming languages includes:

  • QCL – A short for Quantum Computation Language, this is one of the first programming languages implemented in quantum computing. It supports user-defined functions and operators and the data and syntax resemble those of the C programming language.
  • Quantum pseudocode – This is the first formal language used to describe quantum algorithms and was proposed by E. Knill. It is closely connected with a QRAM or Quantum Random Access Machine.
  • Q# – This is a programming language that was developed by Microsoft and is used in the Quantum Development Kit.
  • Q|SI> – This is a platform rooted in .Net language. It allows quantum programming in an extension of quantum while language and includes a series of tools and a compiler that helps to simulate quantum computing, optimize quantum circuits, terminate and verify analysis of quantum programs.
  • Q language – This is used as an extension of the C++ programming language and allows performing basic quantum operations such as QHadamard, QSwap, QFourier, and QNot, all derived from the base class, Qop.
  • qGCL – Short for Quantum Guarded Command Language, this supports Guarded Command Language created by Edsger Dijkstra.
  • QMASM – A short for Quantum Macro Assembler, this is a low-level language used specifically for quantum annealers like the D-Wave.
  • Scaffold – This is more like the C language built on the LLVM Compiler Infrastructure used to optimize Scaffold code.
  • Silq – This is a high-level programming language with a strong, static system.
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On the other hand, the functional quantum programming languages include:

  • QFC, which follows a flowchart syntax
  • QPL, which follows a textual syntax
  • QML, which takes duplication instead of discarding quantum information
  • LIQUi|>, which is a quantum simulation expansion on the F# programming language
  • Quantum lambda calculi, which expands quantum programming languages with a high-order function theory
  • Quipper, which is used as an embedded language with Haskell as the host language
  • funQ, or functional quantum programming language that has an underlying quantum simulator which is a component of a Haskell library having the same name.

How Fast is a Quantum Computer?

A quantum computer is very fast, in fact, hundreds of millions of times faster than a classical or a supercomputer, to respond to information changes quickly and scrutinize an infinite number of permutations and results at the same time.

In simple words, tasks that would take 10,000 hours for a conventional supercomputer to accomplish can be done by a quantum computer in just a few minutes.

The processing ability of the quantum computer is actually enhanced because it does not use a string of electrical impulses or 1 and 0 in a binary manner as it is used in the classical computers for encoding information in bits.

What Problems Can Quantum Computers Solve?

The list of problems that a quantum computer can solve is pretty long and includes everything that is complex and needs computing a humongous amount of data in a short amount of time.

One such example is combinatorics problems that use number theory, graph theory, and statistics.

Some of the other problems that a quantum computer can solve are:

  • Quantum encryption, which prevents eavesdropping and interception of communication to ensure security
  • Simulation of quantum systems, which ensures nothing goes unnoticed
  • ab initio calculations, which help in performing specific tasks such as electron orbital overlap estimation and atomic bonding modeling
  • Supply chain logistics, which needs using brute force algorithms
  • Optimization, which involves finding the optimal weights for neural sets
  • Finance and economics, which involve studying market behavior, disruptive events and prediction using a lot of statistics and several sophisticated graphic models
  • Drug discovery and development, which involves a series of long, time-consuming, expensive, and complicated experimentations
  • Data analysis and weather forecasting that includes different complex environmental variables

Will Quantum Computers Replace the Cloud?

The short answer is no. The abilities of the quantum computers may be high in terms of performance speed and data handling capacity, but they cannot store data for a long time because their memory lasts for only a couple of hundred microseconds at the most.

There are other limitations to this form of computing. It can only become a reality when its limitations are done away with, which includes:

  • Decay or decoherence caused by even the least disturbance in the qubit environment that causes computing errors
  • Data corruption during retrieving computational results
  • Lack of fully developed security and quantum cryptography
  • Need for zero atmospheric pressure, an ambient temperature close to -273°C or absolute zero, and insulation from the magnetic field of earth that may prevent the electrons from moving
  • Operating for a short interval of time making data recovery very hard

Still, the growing interest in quantum computing by major companies like Google, IBM, Microsoft, Visa, JPMorgan Chase and others shows that it has already started to make its presence and significance felt in different fields and may become a reality sometime down the lane.

Why are Quantum Computers a Threat?

It is the advantages offered by the quantum computers due to their unprecedented processing power that make them still a threat.

Their ability to decrypt data and information rapidly makes it easier for people with ill intent to get access to business and even national secrets.

Typically, these computers make data vulnerable, which poses a significant threat to the economy of the country as well as its national security.


Quantum computing is very useful for solving complex problems and is much more different and capable than the usual process.

It is faster as it uses quantum bits instead of bits which also makes it quite a powerful yet complex process.

Though it is used in myriad industries, its limitations restrict its widespread use.

About Puja Chatterjee

Puja ChatterjeePuja Chatterjee is a technical writer with extensive knowledge about computers. She graduated from BIMS. Her expertise includes technology writing and client relationship management gained through over 12 years of experience. Follow Her at Linkedin.