An Introduction to Quantum Computing
The traditional computer is made up of billions of transistors, which are turned on and off to store what is known as a ‘bit’. These bits are placed together in 8’s to form bytes, which are then packaged as kilobytes and so on. The more complex a command is the greater the number of bits is required to execute the function. Hence, when researchers were initially developing computers, the power of machines had to scale with their size. This is the reason for the giant mainframes of the past. Breakthroughs in semi-conductor technology, notably with silicon, enabled companies to drastically reduce the size of a transistor. Recent decades have seen an exponential increase in computational power by cramming chips with as many nodes as physically possible. This has resulted in modern day cell phones being vastly more powerful than the technology used to land the first rockets on the moon.
Unfortunately, we are beginning to reach a physical limit to the size of transistors. The most modern transistors are 7nm in length, in other words barely larger than an atom! Continuing on this path we will eventually reach a point where the laws of classical physics are no longer applicable to measure whether bits are ‘on’ or ‘off’. This is because in the quantum (very very very very small) scale, particles begin to display properties of superposition. Put simply, their position is not fixed until they are measured. Therefore, if we are to advance our computational capabilities, researchers will need to look to new methods like Quantum computing to solve problems too complex for current technology.
What is Quantum computing?
Quantum computing relies on the manipulation of quantum bits, also known as qubits. Qubits can take the value of 1, 0 or anything in-between (superposition), which allows them to send exponential amounts of information compared to bits. For example, four pairs of bits would be required to send the same information as a single pair of qubits. This scales exponentially, meaning that a 50-qubit system would be able to outperform the modern-day supercomputer.
While this may sound simple enough, there two leading methods of manipulating qubits are very difficult. The first traps individual ions in a vacuum using electric and magnetic fields. The other requires powerful magnetic fields and the cooling of particles to near 0 Kelvin (the theoretical point where atoms would cease to move).
Why is the cloud relevant for the implementation of quantum computing?
Researchers expect access to quantum computing to be through the cloud due to the complex machinery requirements. Don’t expect to be having a super-magnet lying around in your basement anytime soon. Instead, researchers will able to access existing facilities through the cloud. IBM has already launched a 5-qubit processor that has been used to conduct over 300,000 quantum experiments and 15 research papers. Other companies like Google are developing similar technologies however they will wait till they can have a 50-qubit system before making it commercially available.
What are the applications of quantum computing?
The natural world around us behaves in a quantum manner. Being able to simulate this with quantum methods, rather than binary, will enable a better understanding of what actually happens in various reactions. Perhaps the most revolutionary impact of this will be in chemistry. For example, a better understanding of how chemo-therapy reacts with a variety of tumors and cancers would manifest as leaps and bounds in drug discovery. Breakthroughs in encryption and AI are other possible applications.
We are only beginning to equip ourselves with tools for quantum computing and it will be many years before it is successfully implemented. However, it is hard not to get excited about this technology that could revolutionize the way our society operates.
Sources:
http://news.stanford.edu/press-releases/2017/05/09/new-materials-brg-closer-reality/
http://www.nature.com/news/ibm-s-quantum-cloud-computer-goes-commercial-1.21585
http://www.purdue.edu/newsroom/research/2012/120219KlimeckAtom.html
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2 comments on “An Introduction to Quantum Computing”
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Thank you for summarising a topic that I never really knew what’s the basics behind it. IBM seems to be the company most outspoken about their quantum project. Google though announced that they expect to have a 49-qubit system by the end of the year, I read recently. That’s not that far away.
Jeff Weiser form IBM talked about energy efficiency in computing last Friday in class. I have never heard anything in that direction regarding quantum computers. It would be interesting to know how much progress theses systems make in this context.
No problem mSam, glad you liked it! Aside from IBM there’s a company called D-wave that claims to have a quantum computer numerous times the amount IBM is capable of. The reason I did not include this in the article as there were a few sceptics regarding the authenticity of the claims, and I’m definitely not equipped with the adequate knowledge set to provide a relevant opinion. Without going into much detail there are different levels of quantum computing, IBM’s is considered a universal system whereas some experts are saying D-Waves is not.
To answer your second point there is a race to get commercially viable quantum computers onto the cloud. I believe IBM’s next release will be 17 qubits sometime this year. It’ll be interesting to see how Google’s implementation goes, while they might claim to have superior computing power they lack the experience IBM has had on the cloud.
Lastly, I suspect that there is a while to go in refining the methods used to control qubits. Given the complex nature of the machineries there are a lot of areas for improvement for researchers to go.
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