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Quantum Computers: What are they and why are they so important?

Quantum Computers

As research and investments continue to expand in the strange world of quantum computing, we look back at what the tech is about, who are the big players, and what the future holds.

“God doesn’t play dice with the universe.” These are the words of one of the greatest physicists of all time—Albert Einstein. Derived from one of his letters to Max Born (one of the fathers of quantum mechanics), this is Einstein making his dissatisfaction known towards the laws of quantum mechanics. And honestly, I don’t blame him. The notorious puzzles and paradoxes of quantum mechanics ensure that the more you learn about it, the less you learn about it. But for the sake of this article, let’s define it simply as the mind-bending branch of physics that explains how everything works; it’s the framework to our universe, the underpinning of all that exists. 

Quantum mechanics has paved the way for humanity’s comprehension of the physical universe over the years. And now, it’s set to revolutionize the world of computing that, if successful, will result in the biggest performance boost in the history of technology.

Quantum computing has the potential to alter dramatically the course of humanity, making strides in the fields of medicine, communications, and artificial intelligence. But what exactly is it and how does it work? Uncertainty has always been a staple at the quantum level, but even as I answer these questions, it’s important for you to understand that we’re barely even scratching the surface here. 

What is Quantum Computing?

We’ll get to that soon enough, but before that, there are some core principles that you need to understand. You may already know that binary bits, or information stored in the form of ones or zeros, are used by traditional computers. These are tiny switches that can be in either the off (represented by a zero) or the on (represented by a one) position. Every e-book you read, every website you visit, and every digital photo you take is made up of millions of these bits in one combination or the other. However, the universe doesn’t work this way. Things aren’t just on or off, when it comes to the atomic level. In the quantum world, we use the language of probability rather than certainty. In the context of computing based on binary digits (bits) of 0s and 1s, quantum bits (qubits) behave in a completely different way, with some having the likelihood of being a 1 and some of being 0 at the same time. Quantum computers isolate these qubits in a controlled quantum state and harness this quirky characteristic to exponentially increase performance. There are two properties of quantum physics that scientists are trying to exploit efficiently: one is superposition and the other is entanglement. 

Super What? Ental Who?

The easiest way to understand superposition is to spin a coin. When the coin stops and rolls over, we know it’s either going to be heads or tails. However, while the coin is still spinning, it can be either. The spinning coin can be likened to the state of superposition. Similarly, a quantum particle in a superposition state is a linear combination of an infinite number of states between 1 and 0, but you can’t tell which one it is unless you look at it. A fascinating example of visualizing superposition is the double-slit experiment (I recommend you to watch this on YouTube to understand how staggeringly inconceivable this phenomenon is). Entanglement is another counter-intuitive phenomenon that exists in quantum physics, where two or more quantum particles become entangled. While in this state, they form a single system. So, if you spin an entangled qubit, the measurement on any qubit will always be correlated to the measurement on the qubit you observe. This is always the case, even if the particles are separated from each other by a large distance—a characteristic that simply doesn’t adhere to any of the known laws of physics. 

Now I know this all sounds like hokum and I empathize with you—Even now, physicists also don’t fully understand how or why the quantum world works the way it does. However, we’ve managed to make quantum computers move that information around, utilizing its uncertainty to perform complex calculations. You could solve problems that would take our best computers millions of years if you can manage to string together many qubits. And trying to string multiple qubits along is exactly the stage we’re at in terms of progress in this realm.  

Why Don’t They Look Like Regular Computers? 

A qubit can be knocked out of its fragile state of superposition by just about everything. As a result, quantum computers must be kept free of all electrical interference and at temperatures close to absolute zero—colder than the farthest reaches of the universe. What you see when you search for quantum computers on the internet is actually mostly the cooling station for the chip. 

The Race For Quantum Supremacy 

In 2019, Google claimed that it has achieved quantum supremacy by developing a quantum computer called Sycamore, which could perform a test computation in just 200 seconds, compared to the most powerful supercomputers that take 10,000 seconds to complete. That met the definition for quantum supremacy—the moment a quantum machine does something unfeasible for a conventional computer. But IBM researchers argued in a blog post “that an ideal simulation of the same task can be performed on a classical system in 2.5 days and with far greater fidelity.” Google, IBM, Intel, Amazon, and Microsoft have all expanded their teams working on the technology, with a growing swarm of startups such as Rigetti, Atom, Xanadu, and D-Wave in hot pursuit. China and the European Union have also introduced new multibillion-dollar schemes to promote quantum R&D. This has very obviously turned into a race. But what’s at the finish line? Your guess is as good as mine as the potentials are still undetermined. 

When Google announced that it had achieved “quantum supremacy,” that machine operated on 54 qubits. While IBM’s Q 53 system operates at a similar level, many prototypes operate on as few as 20 or even 5 qubits. That’s still far fewer than would be needed to do useful work with a quantum computer—it would probably require at least thousands.

So while we are still a good couple of decades before quantum computers can make some real-world impact, we’re still hopeful. Just like how traditional computers brought along changes that were beyond belief 30 years ago, quantum computers will do the same—but for subjects far more complicated than the human mind can comprehend. 

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