Left: A lattice of 2000 qubits, chilled close to absolute zero to harness quantum effects. Below: A look inside the D-Wave 2000Q™ System. Photos courtesy of D-Wave. For more information, go to dwavesys.com.
information about one particle can reveal information about its pair. For example, if an electron spinning up on Earth is entangled with an electron on Mars, then we automatically know that the electron on Mars is spinning down. Subatomic particle behavior can be strange, but is intricately woven into the fabric of the universe.
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Let’s Break Down Quantum Computing An introduction to the most disruptive technology of our time BY TANISHA BASSAN
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he past decade has seen a rapid and continuous growth of computation power, a phenomenon that’s consistent with the predictions outlined in Moore’s Law*. This increase has led to numerous technological innovations, such as graphics processing units that are powerful enough to run machine learning algorithms and virtual reality simulations, and host entire blockchain ledgers. However, as our transistors decrease in size, Moore’s prediction that computational power will reach a plateau comes into view. As the scale of chips reach an atomic size, the laws of quantum mechanics start interfering with the quality of energy transfer in the circuits. To continue pushing the limits of what is possible with computation, renowned theoretical physicist Richard Feynman pioneered the field of quantum computing, which utilizes laws of quantum mechanics to enable computational power in ways we’ve never seen before. *The prediction that the overall processing power for computers will double every two years (mooreslaw.org). 42
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Superposition and entanglement
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uantum mechanics details two rudimental laws of how subatomic systems behave: superposition and entanglement. First, superposition is what allows an electron to be in all places at the same time through wave-particle duality; simply put: it describes how electrons can act like a wave. Imagine if I draw an ‘X’ on a page of a book in a library filled with millions of other books and ask someone to find it. This would classically be done by going through every page of every book until they find the X, which is a daunting task, to say the least. But if the person were in superposition, they would have the ability to look at a large number of pages and books simultaneously, drastically reducing the time needed to find the ‘X.’ This is the essential premise of quantum computers. Second, entanglement is the unique connection between two subatomic particles, which doesn’t break no matter how far the particles are from one another. This property is special because knowing
January 2019
uperposition and entanglement form the basis of how quantum computing works, and qubits are the quantum bits that use these properties to transfer information. Examples of qubits include superconducting, photonic, topological, and trapped ions. The scientific community still has to come to a consensus on which qubit is best for quantum computers. Qubits are placed on a quantum circuit along with gates, which are operations performed on each qubit to put them into a superposition state. The most common circuit design uses superconductors where electrons can flow left, right, or superposition in both directions. There are already companies making
