What Is Quantum Computing? An In-depth Explanation

TL;DR: Quantum computing represents a revolutionary paradigm shift in computational capabilities compared to traditional classical computing. A quantum computer has the potential to store significantly more information and execute highly efficient algorithms, resulting in the rapid resolution of exceedingly intricate tasks.

By Julian Wallis
14 min read

Quantum computing stands as a beacon of innovation in the realm of cutting-edge technology. Quantum computers can potentially revolutionise industries, from cryptography and pharmaceuticals to artificial intelligence and logistics. 

In this article, we delve deep into the fascinating world of quantum computing, exploring its capabilities, applications, and promise for the future.

What is Quantum Computing?

Quantum computing is not just an evolution of classical computing; it’s a paradigm shift.  At its core, quantum computing leverages the principles of quantum mechanics to process and manipulate information fundamentally differently from classical computers. 

While classical bits can only be either 0 or 1, quantum bits or qubits can exist simultaneously in multiple states due to superposition. This unique property allows quantum computers to handle complex calculations exponentially faster than their classical counterparts.

Quantum Computing vs. Classic Computing

In the face of daunting challenges, scientists and engineers often turn to the immense power of supercomputers. These technological marvels boast vast arrays of classical CPU and GPU cores, equipped to tackle colossal calculations and cutting-edge artificial intelligence tasks. Nevertheless, even these supercomputers, built upon 20th-century transistor technology, encounter their limits when grappling with particular types of problems.

When a supercomputer finds itself perplexed, it’s typically because it has been tasked with solving a highly intricate problem. The complexities that classical computers struggle to unravel are fundamentally tied to the very nature of intricate problems.

Complex problems, by definition, involve a multitude of variables intricately interacting with one another. Take, for instance, the intricate dance of electrons within a molecule—an example of the formidable complexity that classical computers face when modelling atomic behaviour. Likewise, pinpointing subtle patterns of fraudulent activity within vast financial transactions or uncovering new realms of physics within the confines of a supercollider presents another set of intricate challenges. There exist, however, certain complex problems that classical computers, regardless of their scale, remain unable to conquer.

In the grand tapestry of our reality, quantum physics reigns supreme. The future beckons with the promise that computers harnessing the quantum states of quantum bits will emerge as our most potent instruments for comprehending this intricate realm.

How Are Quantum Computers Better Than Classic Computers?

Quantum computers offer a profound leap in computational power, and here’s a hopefully compelling example that illustrates their superiority over classical counterparts.

The fundamental distinction lies in the stark contrast between quantum and classical computing paradigms. Quantum computers harness qubits, which possess the remarkable ability to exist as both 1 and 0 simultaneously, in stark contrast to classical computers that rely on bits, limited to singular values of 1 or 0. This inherent difference in computational architecture empowers quantum computing with unparalleled speed and potency. Its promise extends to the realm of tackling an array of exceptionally complex and impactful challenges.

Imagine a classic computer tasked with sifting through an extensive database of molecules. While it may excel at straightforward tasks like sorting, it faces insurmountable hurdles when dealing with more intricate challenges, such as simulating the behaviour of these molecules.

Today, considering the current state of molecular science, understanding how a molecule behaves often necessitates real-world experimentation—a costly and time-consuming process. Researchers typically must synthesise the molecule and conduct physical experiments. If they wish to explore the effects of slight modifications, they must repeat the entire process. This bottleneck stifles progress across diverse fields, from medicine to even semiconductor design.

Classical supercomputers could attempt to tackle the simulation of molecular behaviour through sheer computational force. They might deploy numerous processors to explore every conceivable behaviour of each molecule’s constituent parts. However, as the complexity of molecules increases, even the most powerful classical supercomputers will inevitably hit a wall. None possess the requisite working memory to handle the myriad permutations of molecular behaviour using traditional methods.

Here’s where quantum algorithms take centre stage in solving these intricate problems—they construct multidimensional computational spaces. This innovative approach proves vastly more efficient when tackling complex challenges like chemical simulations. 

Classical computers need the capability to generate these computational spaces effectively, rendering them less useful with the aid of quantum computation. Industrial chemists have already embarked on the journey of incorporating quantum methodologies into their work, and this is just the tip of the iceberg. Engineering firms, financial institutions, global shipping conglomerates, and numerous other sectors are exploring how quantum computers can tackle pivotal issues within their domains. 

An impending wave of benefits from quantum research and development looms on the horizon. As quantum hardware scales up and quantum algorithms advance, we can anticipate breakthrough solutions to complex problems, such as molecular simulations, becoming increasingly attainable. That’s the potential of quantum computing!

How Does Quantum Computing Work?

To understand what the theory of quantum computing is all about, let’s first do a scientific debrief on computing as a concept in general. A traditional computer we use in our daily lives, whether it’s our laptop, smartphone, tablet or smartwatch, is made up of very simple components doing very simple things – representing data, processing it, and employing control mechanisms. Computer chips contain modules, which contain logic gates, which contain transistors. 

A transistor is the simplest form of a data processor in computers, basically, a switch that can either block or open the way for information coming through. This information is made up of bits, which can be set to either 0 or 1. Combinations of several bits are used to represent more complex information. Transistors are combined to create logic gates, which still do very simple stuff.

For example, an AND Gate sends an output of 1 if all of its inputs are 1 and an output of 0 otherwise. Combinations of logic gates finally form meaningful modules, say, adding two numbers.

Understanding Quantum Physics

Once you can add, you can also multiply, and once you can multiply, you can basically do anything. Since all basic operations are literally simpler than first-grade math, you can imagine a computer as a group of 7-year-olds answering really basic math questions.

A large enough bunch of them could compute anything from astrophysics to Call of Duty. However, with parts getting tinier and tinier, quantum physics is making things tricky.

In a nutshell, a transistor is just an electric switch. Electricity is electrons moving from one place to another. So, a switch is a passage that can block electrons from moving in one direction. 

Today, a typical scale for transistors is 14 nanometers, which is about 8 times less than the HIV virus’ diameter and 500 times smaller than a red blood cell. As transistors are shrinking to the size of only a few atoms, electrons may just transfer themselves to the other side of a blocked passage via a process called Quantum Tunneling.

In the quantum realm, physics works quite differently from the predictable ways we’re used to, and traditional computers just stop making sense. We are approaching a real physical barrier to our technological progress. To solve this problem, scientists are trying to use these unusual quantum properties to their advantage by building quantum computers.

The Science Of Quantum Computers 

In normal computers, bits are the smallest unit of information. Quantum computers use “qubits”, which can also be set to one of two values. A qubit can be any two-level quantum system, such as a spin and a magnetic field, or a single photon. 0 and 1 are this system’s possible states, like the photons’ horizontal or vertical polarization.

In the quantum world, the qubit doesn’t have to be just one of those; it can simultaneously be in any proportion of both states. This is called superposition. But as soon as you test its value by sending the photon through a filter, it has to decide to be either vertically or horizontally polarised. So, as long as it’s unobserved, the qubit is in a superposition of probabilities for 0 and 1, and you can’t predict which it’ll be. You could say it’s in a mixed state between the two. But the instant you measure it, it collapses into one of the definite states.

Superposition is a game changer. Four classical bits can be in one of two to the power of four different configurations at a time. That’s 16 possible combinations, out of which you can use just one. Four qubits in superposition, however, can be in all of those 16 combinations at once. This number grows exponentially with each extra qubit. Twenty of them can already store a million values in parallel. That’s ridiculous, right?

A really weird and unintuitive property qubits can have is Entanglement,

a close connection that makes each of the qubits react to a change in the other’s state instantaneously, no matter how far they are apart. This means when measuring just one entangled qubit, you can directly deduce the properties of its partners without having to look.

Qubit Manipulation is a mind-bender as well. A normal logic gate gets a simple set of inputs and produces one definite output. A quantum gate manipulates an input of superpositions, rotates probabilities, and produces another superposition as its output.

So a quantum computer sets up some qubits, applies quantum gates to entangle them and manipulate probabilities, and then finally measures the outcome, collapsing superpositions to an actual sequence of 0s and 1s. What this means is that you get the entire lot of calculations that are possible with your setup, all done at the same time. 

Ultimately, you can only measure one of the results, and it’ll probably be the one you want, so you may have to double-check and try again. But by cleverly exploiting superposition and entanglement, this can be exponentially more efficient than would ever be possible on a normal computer. So, just imagine the possibilities here. This is a level of computing power that current computers cannot even comprehend.

Key Advantages of Quantum Computing

Speed and Efficiency

One of the most significant advantages of quantum computing is its unparalleled speed and efficiency in solving complex problems. Tasks that would be almost impossible for classical computers, quantum computers can complete in a matter of seconds. This capability opens doors to new possibilities in fields such as cryptography, optimisation, and simulations.

Cryptographic Breakthroughs

Quantum computing poses both a threat and an opportunity for cybersecurity. With its superior processing power, quantum computers can break traditional encryption methods. However, they can also enable the development of quantum-resistant encryption techniques, ensuring data security in the post-quantum era.

Drug Discovery and Material Science

Quantum computing’s immense computational prowess makes it an invaluable tool for drug discovery and material science. Researchers can simulate the behaviour of molecules and materials at the quantum level, accelerating the development of new drugs and materials with revolutionary properties.

Artificial Intelligence

Quantum machine learning is poised to revolutionise the field of artificial intelligence. Quantum algorithms can analyse vast datasets with unprecedented speed, enabling more accurate predictions and insights in areas like natural language processing and image recognition. We’ll get more into this later.

Current Limitations In Quantum Computing

Quantum computing, while brimming with promise, grapples with several notable limitations at the moment in time:

Decoherence and Fragility: Quantum computing is highly susceptible to decoherence, where even the slightest environmental disturbance can lead to the collapse of computations or introduce errors. To ensure accuracy, quantum computers must operate in an environment shielded from all external interference during computation.

Data Corruption during Retrieval: The retrieval of computational results in quantum computing can risk data corruption. However, promising developments, such as specific database search algorithms, aim to mitigate this issue by ensuring that measurement actions lead to the correct quantum state, preventing decoherence.

Incomplete Quantum Cryptography: While brimming with potential, the field of quantum cryptography has yet to reach full maturity in terms of security. Advancements are needed to harness the full power of quantum computing for secure communication.

Limited Qubit Availability: The scarcity of qubits represents a fundamental constraint in quantum computing. Researchers have struggled to produce quantum computers with more than 128 qubits, preventing these machines from realising their full potential for transformative applications.

These limitations underscore the ongoing challenges in harnessing the immense potential of quantum computing, pointing toward the need for continued research and innovation to overcome these hurdles.

Quantum Computing in Practice

Quantum Hardware

The heart of quantum computing lies in quantum hardware. Quantum processors, typically cooled to near absolute zero, manipulate qubits to perform calculations. Leading companies like IBM, Google, and Rigetti are in a race to develop increasingly powerful quantum hardware.

Quantum Software

Quantum software plays a pivotal role in harnessing the potential of quantum computers. Developers use quantum programming languages like Qiskit and Cirq to create quantum algorithms that address real-world problems. This intersection of hardware and software is where quantum computing truly shines.

Future Prospects Of Quantum Computing

The journey of quantum computing has just begun, and its full potential is yet to be realised. As technology advances, we can expect quantum computers to become more accessible and affordable, ushering in a new era of innovation. Industries will continue to harness the power of quantum computing to solve complex problems and reshape the way we live and work. We will also continue to see quantum computing paired up with other emerging technologies. One of which could be artificial intelligence (AI).

What If Quantum Computing Combines With AI?

AI has been the talk of the town in this past year or so, especially with the rise of tools such as ChatGPT. It goes without saying, but ChatGPT has changed the way we search for information online and has taken “productivity tools” to a whole new level. So, with the rise of AI and Machine Learning, what if it were to be used alongside Quantum Computing? What unique possibilities would that combination bring forward?

It’s important to understand that AI and Quantum Computing are fundamentally two different ideologies in that AI is concerned more with the software side of technology, while Quantum Computing is much vaster and concerns itself with the hardware aspect. So, if these two revolutionary hardware and software technologies were to align, then we could be looking at the next big thing in technology.

Quantum computing combined with AI

At the moment, generative AI tools like ChatGPT can find what you’re looking for and present it to you, and it’ll look reasonable. But the interesting part is the tool itself doesn’t know if the information it gives you is factual or not. All it knows is it was on the internet somewhere, and it fulfils the request of your prompt. So, how do you add a new layer of smartness into these AI tools so that they can discern between right and wrong and provide original answers that may not be available anywhere on the internet? Well, that’s where quantum computers can help.

Quantum computing can theoretically act as a fact-checker for these AI tools, hence giving them the ability to differentiate between high-quality resources and low-quality or inaccurate ones. This means improved quality of responses from the AI tool in relation to accuracy, authenticity and originality. In essence, by aligning with quantum computing, these productivity AI tools will have an enhanced objective fact-checking capability instilled within them, which would be game-changing for sure.

Although quantum computing presently grapples with certain limitations, its trajectory suggests integration into the operational framework of numerous high-profile corporations spanning diverse industries. The potential for quantum computing to revolutionise problem-solving remains on the cusp of realisation.

Conclusion – So, What Is Quantum Computing?

In this article, we’ve explored the world of quantum computing, from its foundational principles to its practical applications. Quantum computing’s speed, efficiency, and versatility make it a force to be reckoned with in the world of technology. Quantum computing represents a revolutionary shift in computational capabilities compared to traditional classical computing. A quantum computer has the potential to store significantly more information and execute highly efficient algorithms, resulting in the rapid resolution of exceedingly intricate tasks.

The potential of quantum computing is nothing short of revolutionary, promising to unlock new frontiers in computation that were once considered impossible. As we embark on this exciting journey into the quantum realm, there has never been a more critical time for organisations to harness this cutting-edge technology to enhance their Digital Customer Experience (DCX). 

We invite you to book a discovery call with our expert consultants to seize the incredible opportunities that lie ahead. Let us guide you through intuitive technologies like this and tailor solutions to propel your organisation into a future where innovation knows no bounds. Together, we can transform how you do business and ensure you remain at the forefront of the digital age.

Published on September 15, 2023

Share this post


Related Articles & Content

Clients We've Worked With


How can we help you today?