By Harrison York
Quantum computing faces significant scientific challenges, as researchers learn to navigate the as yet undiscovered quantum world. But despite these hurdles, there is constant progress being made in the field of quantum computing. As more companies and research groups enter into the race to create the most powerful and accurate quantum computers, new various methods of overcoming the challenges of quantum computing are devised and tested. With some methods proving to be more promising than others, there are frontrunners leading the industry.
But let’s take a step back from quantum computers for a moment. It isn’t just quantum computers that use quantum mechanics, but instead a greater industry emerging through the application of quantum mechanics. The study of quantum mechanics (the study of processes that occur between the smallest particles of matter) has revealed a “quantum microworld” that behaves very differently from our own. From the human perspective, classical physics is logical. Through centuries of work and observations, we’ve learned to make predictions about how objects interact and the forces that act on them. In the quantum world however, electrons and other subatomic particles have introduced new rules we haven’t encountered yet, adding probability and chance to interactions.
As hypotheses explaining quantum phenomena were proposed and tested, the scientific community gradually worked through the mysteries and has tentatively created a framework of understanding of the quantum world. This foundation has been harnessed to drive the development of quantum computers.
While quantum computers are not yet widely available, promising progress is being made by an array of players in this burgeoning frontier.
One major challenge in quantum computers is creating a qubit -- or quantum bit -- that rarely experiences errors. Qubits are currently very unreliable due to the difficulty of creating and maintaining them as they face constant decay due to “noise” from the environment interacting with them. Quantum “noise” can occur in the form of temperature changes, which is why today’s systems are kept in a below-zero chamber; signal interference, such as stray radio or other electromagnetic waves can decay qubits; and even the tools that measure them can affect these fragile bits. With qubits being so small and delicate, it is extremely difficult to read them without affecting their state, resulting in errors called tunneling defects that are caused by the decay of qubits.
Earlier this year, a research team based in Russia and Germany presented a study in which a sensor within the quantum computer was created to also act as a qubit, allowing the researchers to detect defects and manipulate the other qubits. Professor Alexey Ustinov, Group Head at Russian Quantum Center, led the effort and explained that this development would surpass the traditional use of small-angle x-ray scattering, which is not precise enough to identify single defects, and may open the door to further research on tunneling errors in order to find more ways to limit their likelihood and improve the reliability of quantum computers.
In contrast, Honeywell, an engineering corporation, has made progress with a different approach to the issue, releasing information on its own quantum computer in a peer-reviewed journal. Unlike Google, IBM, and research groups like the one led by Ustinov, this machine uses trapped ions instead of qubits to make computations. This is because ions can advantageously interact with each other in an enclosed space while qubits have to be hardwired into the quantum system in order to be measured. Similarly to qubits, issues arise in trying to maintain large quantities of these ions, but Honeywell has demonstrated a way to solve this problem by allowing ions to exist dynamically, interacting with one another in a small volume. This permits greater numbers of ions to exist and a greater number of possible interactions to occur. Pursued further, using ions to complete calculations may prove to be more stable and thus more scalable than qubits.
In addition to developments made in the lab, quantum technology is becoming more readily available to curious scientific minds around the world. The Department of Energy in the United States recently opened Sandia National Laboratories’ Quantum Scientific Computing Open User Testbed, or QSCOUT, to the public. “The goal of the project is to help the quantum community by giving users the controls to study the machine itself, which aren’t yet available in commercial quantum computing systems,” said Susan Clark, the physicist leading the team. Research proposals can be submitted to the Department of Energy and a group of such projects will be selected to use the machine for free.
Another effort to provide greater access to quantum technology is IBM’s Qiskit Metal. This is an open-source program that allows users to design quantum hardware. The software automates many steps in the process of idealizing such products, and what would normally take a researcher months can now be done by an average user. Goals are set for the performance of the quantum chip, and then simulated tests are run to predict how the device would act in terms of qubit reliability, entanglement, and other quantum computing processes.
The Qiskit team worked alongside the Chalmers University of Technology to ensure that the simulations were accurate, and they were able to design a successful eight-qubit chip in just 30 minutes. While the program is not meant to construct large-scale systems, it gives users the ability to experiment with quantum principles and learn through trial-and-error.
Qiskit software by IBM: education in quantum computing without expertise requirements. Credit: flickr, @IBM_Research
In a recent opinion article in the Scientific American, writer John Horton questions whether quantum computing will “ever live up to its hype.” This field is a hot topic, and is surrounded by a science-fiction-like fascination as people imagine the impossible things quantum computing may one day do. But science should be powered by logic, and the emotions of excitement can sweep us up in inaccurate predictions for quantum computing technology. Although Horton expresses his doubts and reservations about the future of quantum computing completely altering the world in the near future, the steady progress apparent through parallel work by many different companies have shown that this field will continue to conduct research and improve designs. Quantum computers will not be here tomorrow, and they may not ever be as we imagine, but there is significant potential in the industry for growth and expansion.
Why are quantum computers not widely available?
It takes time to develop new technology, especially with science that is difficult and, in many ways, distinct from previous advances. Researchers are still working on unraveling the complex processes of the quantum world, and harnessing such processes in computers is no easier. Today, quantum computers are large, demanding, complicated, and truly impractical in their limited potential. They are also expensive, and only with more time and improvements will such obstacles be overcome. As progress continues, the applications for this technology will also become more clear, and there is a possibility that quantum computers will only be practical for certain tasks, tasks that the average computer user wouldn’t need to complete, and so they may remain a specialized branch of computing.
How are problems with quantum computers currently being addressed in the field?
The array of companies working on developing quantum computing technology have differing approaches to the main complications. Google, IBM, and other research groups are trying to use qubits and their property of superposition to develop powerful quantum computers, while another group of companies including Honeywell and IonQ are pursuing a solution by using ions. In questions of scale and cooling, companies are similarly trying different ways of mitigating the current issues, and progress in the various methods is expected to eventually reveal the superior methods in quantum computing. Basically, the companies are all using a form of trial and error as they all try to develop more powerful and accurate computers than the others.
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