By Casimer DeCusatis
As far back as the early 1980s, Richard Feynman suggested that quantum computers might offer significant advantages over classical computers in solving certain problems in physics and chemistry. More recently, we’ve come significantly closer to overcoming the many theoretical and experimental obstacles which make practical quantum computing so difficult. The emerging field of quantum information science and technology (QIST), which covers inter-disciplinary topics including communications, computation, metrology, and sensing, will be an emerging topic at the upcoming OFC conference. In this blog, we’ll take a quick look at some of the important themes being addressed and the role photonics plays in QIST hardware and systems.
Research advancing to practical computing architectures
Many collaborative efforts around the world, including the U.S. National Quantum Initiative, are attempting to translate theoretical physics advances into practical quantum computing architectures. Quantum computing promises the ability to execute certain tasks exponentially faster than traditional computational methods. Recently, quantum computers have been demonstrated based on qubits (nonclassical bits formed by a superposition of different states, rather than having one of two possible binary values). These systems form qubits from electron states, and require cryogenic temperatures to operate, even approaching the temperature of deep space to within a few millikelvin. This type of qubit is very fragile, and can easily break down due to small amounts of thermal noise or electromagnetic interference. Thus, most of the hardware required for modern quantum computers is devoted to maintaining a high vacuum, low temperature stable environment shielded from external electromagnetic radiation that might disrupt electron spin states. This is also the fundamental reason why it is so challenging to create a general purpose quantum computer with a large number of qubits.
Recently, both IBM and Google have made progress in this area, with Google reporting a system having 53 programmable superconducting qubits. Amazon recently announced quantum computing as a service in their cloud environment. The search for even more powerful systems and demonstrable computing advantages over classical systems has led to the term “quantum supremacy” being used to describe leadership in this area. The effort isn’t limited to large corporations; some of the early practical applications in this area use a hybrid combination of classical and quantum approaches. For example, the quantum computing company D-wave has also developed an approach based on superconducting processors cooled to 0.015 Kelvin (180 times colder than interstellar space). This system was recently combined with classical computing techniques to solve simulated annealing problems related to highway traffic congestion in large metropolitan areas by calculating optimal vehicle travel routes in near real time.
Research continues for implementation options
While these results are quite impressive, researchers continue searching for alternative implementations which would not require operating systems near absolute zero temperatures. One new proposal would structure photonic qubits at room temperature inside photonic integrated circuits. The concept of entangled photon qubits was postulated as early as 1935, but could not be physically realized until very recently. Possible designs for such a system include photonic logic gates incorporating advanced light sources, sensors, and detectors, polarization modulation, or other optically addressable and controllable qubit platforms. While this is still very much a research field, there is no shortage of interest in the application of quantum computing to practical problems. In particular, financial technology (fintech) solutions are already being patented by large institutions such as Bank of America and others. As noted earlier, interest in this field isn’t limited to U.S. firms or large corporations; many international organizations and smaller start-ups are also investing in the future of quantum computing.
What do you think will be the next big application for quantum computing? Drop me a line on Twitter (@Dr_Casimer) and maybe we can discuss your ideas in a future blog.
Are you conducting research in quantum computing or optical communications? This will be a hot topic at OFC in 2021. Consider submitting a paper. Check out topic categories D2 and N2.
Posted: 17 July 2020 by
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