The dawn of quantum computing

Quantum Computing will fundamentally change the way we operate and compute in the decades to come, this article will cover the basics of quantum computing, and touch upon the challenges it has to overcome to widely adapt as the computing technology of future.

Quantum mechanics — is the foundation on which our physical existence is built. It is one of the most successful theories in modern science. Without it, we would not have such marvels as atomic clocks, computers, lasers, LEDs, global positioning systems and magnetic resonance imaging, among many other innovations.

The trouble is, simulating the quantum mechanics of these systems can be extraordinarily difficult for even the largest conventional supercomputers. The simulation entails keeping track of and performing calculations on a number of variables that grow exponentially with the number of electrons in each molecule. Quantum mechanics is our greatest debt in information technology for a long time.

Researchers hope to use quantum principles to create an ultra-powerful computer that would solve problems that conventional computers cannot — from improving cybersecurity and modeling chemical reactions to formulating new drugs and making supply chains more efficient. This goal could revolutionize certain aspects of computing and open up a new world of technological possibilities. Such algorithms would be useful in solving complex mathematical problems, producing hard-to-break security codes, or predicting multiple particle interactions in chemical reactions.

Significance

Researches predicted that by 2040 we will be reaching the limits of energy efficiency using our classical computing technologies, we're left with no other choice but to find new ways to make computing more efficient.

Wide adoption of quantum will be game changing for every industry and will have a huge impact in the way we do business, invent new medicine and materials, safeguard our data, explore space, and predict weather events and climate change. Most influential companies, like IBM, Microsoft, Amazon, Google and governments are investing heavily in quantum computing technologies. Venture Capitalists are pouring hundreds of millions of dollars into quantum computing startups, even though practical applications are years or even decades away. They believe that quantum computing would change the world because it will allow us to solve problems and experience efficiencies that aren't possible today.

Supercomputers can only analyze the most basic molecules. But quantum computers operate using the quantum properties as the molecules they’re trying to simulate. They should have no problem handling even the most complicated reactions. That could mean more efficient products – from new materials for batteries in electric cars, through to better and cheaper drugs, or vastly improved solar panels. Scientists hope that quantum simulations could even help find a cure for Alzheimer’s.

Quantum vs Classical

Quantum computation is radically different from classical computation. For the most part, we have to start over, from scratch. The difference between quantum computation and classical computation is less like the difference between a propeller-driven plane and a jet aircraft, but more like the distinction between air travel and space travel — there is very little knowledge that transfers in any clean manner. Rather than encountering significant familiarity and similarity, one is faced on all fronts with disorientation and new concepts that are unrelated to the old concepts.

Software developers for classical computers can rely on integer and floating point numbers, algebraic expressions with arithmetic operators and trigonometric functions, conditional branching, looping, and nested functions — but none of these constructs even exists in a quantum computer.

One thing that we do know about the nature of quantum computing is that algorithms that normally have exponentially evolving complexity in supercomputers only have linear growth in complexity when viewed in the eyes of a quantum computer. This is where the potential of quantum computers becomes interesting. As an example, the pharmaceutical industry relies a lot on the skills of designing new proteins. To do that, you need to simulate how they will fold in 3D space. As you try out possible outcomes, the complexity grows exponentially. Except, to a quantum computer, it doesn't. By moving the complexity from exponential to linear behavior, quantum computers reduce years of work to a few minutes.

Every time a quantum computer grows by even a single Qubit, a classical computer will have to double in size to keep pace. By the time a quantum computer gets to 70 qubits — likely within the next few years — a classical supercomputer would need to occupy the area of a city to keep up.

Probabilistic vs Deterministic

Quantum computers work on the principles of probability rather than strictly deterministic like classical computers. This gives immense potential to tackle complex problems that would take our best computers millions of years to solve however this distinction also requires a significant, radical change in mindset for the design of algorithms and code for a quantum computer. This is a new form for computing that can perform calculations based on the probability of an object's state before it is measured instead of just 1s or 0s - which means they have the potential to process exponentially more data compared to classical computers.

Quantum computers are also notoriously fickle. They need tightly controlled environments to operate in. Quantum computers are based on the principles of quantum theory, which explains the behavior of energy and material on the atomic and subatomic level When we enter the world of atomic and subatomic particles, things begin to behave in unconventional ways. In fact, these particles can exist in more than one state at a time. Instead of bits, which conventional computers use, a quantum computer uses quantum bits or qubits.

To visualize the difference, imagine a bubble or sphere. At any given time, a bit can be at either of the two poles of the sphere, but a qubit can exist at any point on the sphere. So, this qubit gives quantum computers an enormous amount of computing power and uses less energy than a typical classical computer. What is interesting is that, in the world of quantum computing, traditional laws of physics no longer apply, we could be able to create processors that are significantly faster (over million times). For instance, eight bits is enough for a classical computer to represent any number between 0 and 255. But eight qubits is enough for a quantum computer to represent every number between 0 and 255 at the same time. A few hundred entangled qubits would be enough to represent more numbers than there are atoms in the universe. This is where quantum computers get their edge over classical ones.

Superposition

Superposition refers to a combination of states we would ordinarily describe independently. To make a classical analogy, if you play two musical notes at once, what you will hear is a superposition of the two notes.

Source: IBM

Quantum superposition is a fundamental principle of quantum mechanics, much like waves in classical physics, any two (or more) quantum states can be added together ("superposed") and the result will be another valid quantum state; and conversely, that every quantum state can be represented as a sum of two or more other distinct states.

Entanglement

Entanglement is a famously counter-intuitive quantum phenomenon describing behavior we never see in the classical world. Entangled particles behave together as a system in ways that cannot be explained using classical logic.

Source: IBM

It is a physical phenomenon that occurs when a pair or group of particles is generated, interacts, or shares spatial proximity in a way such that the quantum state of each particle of the pair or group cannot be described independently. Entanglement is one of the primary properties that differentiates quantum computing from classical computing.

Interference

Finally, quantum states can undergo interference due to a phenomenon known as phase. Quantum interference can be understood similarly to wave interference; when two waves are in phase, their amplitudes add, and when they are out of phase, their amplitudes cancel. 

Source: IBM

Quantum Volume

What does it take to build a fault-tolerant quantum system? To increase the computational power of a quantum computer, improvements are needed along two dimensions.

One is qubit count; the more qubits you have, the more states can in principle be manipulated and stored. The other is low error rates, which are needed to manipulate qubit states accurately and perform sequential operations that provide answers, not noise.

A useful metric for understanding quantum capability is quantum volume. It measures the relationship between number and quality of qubits, circuit connectivity, and error rates of operations. Developing systems with larger quantum volume will lead to discovering the first instances of applications where quantum computers can offer a computational advantage for solving real problems.

Challenges

While we're excited about the opportunities that quantum computing can help with, the challenges are far greater than one thinks. Quantum computing is still most certainly in the research stage, and has many challenges to overcome before it can go mainstream computing. But we all see the enormous opportunities and they are worth pursuing.

Quantum computers have been under development for decades. They aim to harness those features to rapidly perform calculations far beyond the capacity of any ordinary computer. But for years, quantum computers struggled to match the computing power of a handheld calculator. Researchers have made significant advances in recent years on the development of working quantum computers.

In short, we need a far richer algorithmic infrastructure — and hardware which supports it — before we can tackle more than just a few, high-value niche applications.

There are several challenges in building a large-scale quantum computer - fabrication, verification, and architecture. The power of quantum computing comes from the ability to store a complex state in a single bit. This also makes quantum systems difficult to build, verify, and design. Quantum states are fragile, so fabrication must be precise, and bits must often operate at very low temperatures. Unfortunately, the complete state may not be measured precisely, so verification is difficult. Imagine verifying an operation that is expected to not always get the same answer, but only an answer with a particular probability! Finally, errors occur much more often than with classical computing, making error correction the dominant task that quantum architectures need to perform well.

The loss of coherence (called decoherence), caused by vibrations, temperature fluctuations, electromagnetic waves and other interactions with the outside environment, ultimately destroys the exotic quantum properties of the computer. Given the current pervasiveness of decoherence and other errors, contemporary quantum computers are unlikely to return correct answers for programs of even modest execution time.  

But we still have a while to wait before quantum computers can do all the things they promise. Right now, the best quantum computers have about 50 qubits. That’s enough to make them incredibly powerful, because every qubit you add makes an exponential increase in processing capacity. But they also have really high error rates, because of those problems with interference.

Almost anything can knock a qubit out of the delicate state of superposition. As a result, quantum computers have to be kept isolated from all forms of electrical interference, and chilled down to close to absolute zero.

In short, we need a far richer algorithmic infrastructure — and hardware — before we can tackle more than just a few, high-value niche applications. 

Some mathematicians believe there are obstacles that are practically impossible to overcome, putting quantum computing forever out of reach. Nevertheless, there is a race going on among IBM, Google, Microsoft and other large and small private companies, and heavy research is taking place at many universities worldwide. By now, we can assume that quantum computing will eventually massively accelerate many of our scientific and technical processes.

To be clear, yes, I do imagine to see quantum computers to work at room temperature, with the size of a laptop, or a server blade, and even in a handheld device sooner, but there is some bumpy ride ahead before we see it adapt for mainstream computing.

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Vijay Dhanasekaran is the Founder and Principal Consultant at Blocknetics specialized in Emerging Tech - Blockchain, AI, Strategy Consulting and Innovation. He is a futurist and blue ocean strategist passionate about creative problem solving and innovation with future/emerging tech.

Vijay Dhanasekaran help businesses and customers in their digital transformation journey to seamlessly adapt to the creator economy by empowering them with digital first strategy, emerging tech consulting and mentoring. He is also successful at envisioning the future trends and focused to helping companies for their new (digital) normal.