Written by Deepansha Singh
Google’s quantum computing processor has solved a problem in less than 4 minutes, which would take a supercomputer at least 10,000 years to solve.
But how did Google accomplish this extraordinary feat?
What exactly makes quantum computers so powerful? Do they solve all types of problems as quickly as Google’s processor solved this particular problem? What are the differences between classical and quantum computers? Can we leverage this speedup in the future for real-world applications?
Groundbreaking research discoveries are being made on a daily basis in the quantum computing realm. Every day, the research being conducted is helping us answer these types of questions.
Making the leap from classical to quantum
Today, information is encoded using binary. Unlike classical computers that operate on 0s and 1s, quantum computers utilize quantum physics properties such as “superposition” to be in multiple states simultaneously. This difference between quantum and classical computers has been explained by a maze analogy from Microsoft CEO Satya Nadella. Given a maze, with the goal of trying to find a path outside of the maze, a classical computer would try to obtain the solution using “brute force” and explore each path one at a time. However, a quantum computer would explore all potential paths at the same time, or simultaneously, which leads to an immense speedup. This “simultaneous” action is analogous to the quantum physics property that quantum computers utilize called “superposition.”
Quantum computing lies at the intersection of quantum physics, mathematics, and computer science; furthermore, quantum computers harness quantum physics properties such as “superposition” and “entanglement” to enable this exponential speedup.
What types of problems can quantum computers solve?
Quantum computers can provide massive speedups when solving optimization problems. In particular, it has been used in various industries such as financial services, machine learning, healthcare, and cryptography.
Quantum computing can be used in trading optimization. Particular financial services use cases where quantum computing can provide a powerful speedup are optimal arbitrage opportunities (determining how to change currencies with the goal of optimizing the profit), portfolio optimization (determining which assets to choose to optimize the return and risk), and optimal trading trajectory (determining most optimal trading rate). Furthermore, other than solving optimization problems, quantum computing can also provide an immense speedup when trying to simulate uncertainties that are inherently present in particular financial landscapes using Monte Carlo methods.
Quantum machine learning is an emerging field that lies at the intersection of machine learning and quantum computing. Currently, some classical machine learning algorithms don’t run too quickly; however, quantum computing can help with some of these algorithms by providing a massive speedup. Generally, when forming quantum machine learning algorithms for problems, one needs to encode the system into a quantum one and then apply the same classical machine learning algorithm logic on the input. One way quantum computing can help create a speedup in machine learning is with dimensionality reduction- the quantum version of the kernel ML trick for dimensionality reduction is faster than the classical version, which helps with the algorithm speedup.
Quantum computing can also provide a great speedup for the cryptography domain. Currently, modern cryptography (RSA) uses the idea that encryption can’t be broken until you find the factors of a very large number n. However, as this number n gets larger, it’s harder for a classical algorithm to determine these factors quickly. This is where quantum computers come into play. There is a quantum computing algorithm called Shor’s Algorithm (developed by MIT professor Dr. Peter Shor) which has cracked our current RSA encryption method while providing an immense speedup. The following YouTube video exemplifies how Shor’s algorithm breaks modern-day encryption:
Personally, one of my favorite quantum computing applications is teleportation, by harnessing the quantum physics entanglement property. Chinese scientists have teleported photons (light particles) to space. Hopefully, one day, as we continue conducting research in quantum computing applications, we will be able to achieve human teleportation one day!