Rice University: The state of quantum computing

Quantum computing has gone from science fiction to foreseeable reality within our lifetime. From Google to IBM, China to the U.S. — everyone everywhere seems fixated on realizing the power of quantum computing.

But with all the hype and all the noise (yes, pun intended), it’s difficult to tell how far along the development of quantum computing really is. Here’s a brief overview.

Quantum computing makes use of the science of the very small, harnessing the “weird” phenomena of quantum mechanics to give computational power an exponential boost. Though most quantum computers today fill an entire room, their capabilities are all small-scale. Each has less than 100 qubits. While not everyone agrees, many researchers predict that millions of qubits will be required to enable useful quantum computing applications.

Until June, IBM boasted the largest quantum computer in the world, containing 65 qubits. Now, China’s 66-qubit superconducting quantum processor called Zuchongzhi is the reigning champion. Not only does the Chinese quantum computer contain the highest number of qubits yet, but it also beats Google’s claim at quantum supremacy.

The team of researchers responsible for the advancement, led by China’s “father of quantum” Jian-Wei Pan, demonstrated a quantum advantage in Zuchongzhi’s ability to perform a sampling task in 1.2 hours that would take a classical computer an estimated eight years to complete.

While the progress of quantum computing may be measured incrementally, qubit by qubit, the pace of the development has consistently been advanced by a number of diverse players across the globe. To date, 46 countries are engaged in national or international quantum research and development projects. However, most of the action is happening in academia and industry.

Companies like IBM, Google, Microsoft and Honeywell are all building quantum computers, and researchers from universities around the world have founded quantum computing startups.

In June, Forbes reported that Honeywell Quantum Solutions announced it is being spun off from parent company Honeywell International to merge with Cambridge Quantum Computing, with a view to going public as early as the end of the year. That news is evidence investors see a major opportunity in quantum computing and they’re hungry to participate. Private capital is a major driver of the budding quantum computing industry’s rapid growth.

Quantum computing holds vast commercial and geostrategic value. Though there’s competition at both national and global levels (it’s often called a “race”), the quantum computing landscape is full of international teams and global, multidisciplinary institutions.

The destination of quantum computing — the finish line of the quantum “race” — is still unclear.

Previously, a quantum computer’s ability to demonstrate “supremacy” over classical computers by calculating the solution to a specific, narrow function was thought to represent an important benchmark in the development of quantum computing. However, once Google claimed quantum supremacy it became clear that while it’s impressive, the accomplishment demonstrated little real-world value.

Other efforts to track the development of quantum computing technology are in development. The Defense Advanced Research Projects Agency recently announced it would establish key quantum computing metrics with the goal of making those metrics testable, in order to track the utility of the technology over the coming decades.

Realizing some of the future applications of quantum computing may also provide more meaningful benchmarks. One of the best known quantum computing applications is its potential ability to break encryption, blockchain and the internet as we know it. Governments around the world are preparing for this eventuality by investing heavily in secure quantum communications, building quantum-enabled internet networks and exploring quantum-proof cryptography.

An important area of future use of quantum computers will be simulation, especially when used with other technologies like artificial intelligence. In health care, quantum computing could help us develop new drugs by allowing researchers to simulate larger, more complex molecules. A quantum-enabled approach to drug development could make the process both cheaper and quicker. This could change the face of personalized medicine, giving us the ability to rapidly develop drugs to treat uncommon illnesses that don’t currently receive the attention of the pharmaceutical industry.

Quantum computing also holds major promise for modeling applications in areas like environmental impact. In the future, quantum computers could be used for high-precision weather forecasting. More accurate climate modeling could help paint a more accurate picture of the catastrophic threats of climate change, providing us with a far better understanding of the risks we face and how we can counter them.

Many companies are already in the R&D stages of imagining quantum-enabled solutions to persistent problems. Samsung wants to improve battery technology, BMW is looking to optimize its supply chains and Volkswagen aims to reduce traffic congestion.

Diverse businesses and industries are beginning to explore what quantum computing could offer. In biology, quantum computers could be used to accelerate some bioinformatics calculations. In the financial services industry, they could be used to detect fraud and optimize trading.

The next step is to build bigger. We will need much larger and more powerful quantum computers if we want to use them for solving real-world problems. IBM has set an ambitious quantum road map with the goal of building a number of machines with as many as 1,000 qubits by 2023. And both Google and IBM plan to build a million-qubit quantum computer within 10 years. But there are a few major technical challenges to surmount before we get there.

Qubits are incredibly fragile. Even the slightest variance in vibration, radiation, electromagnetic waves or temperature can knock them out of coherence. And the more qubits one wishes to add, the more difficult it becomes to keep them in coherence.

A recent Nature article showed that background radiation and even incoming cosmic rays can trigger decoherence in qubits. Managing this problem will require a new approach. The answer could be making more resilient qubits, shielding qubits with better or novel materials, or switching the environment in which quantum computers currently operate (perhaps inspired by Microsoft’s experiment of putting a data center underwater).

The fragile nature of quantum information makes environments built to house quantum computers complex and expensive. Most quantum systems can only operate in sealed, vacuumlike environments colder than deep space, which requires laboratories to install specialized, energy-intensive refrigerators. Some quantum systems are made using rare materials, which presents ethical and ecological challenges.

As daunting as these challenges may seem, researchers around the world are making progress in conquering some of quantum computing’s most pervasive technical problems. Recent work could allow quantum processors to operate at more reasonable temperatures and quantum error correction codes are now being developed.

The quantum development landscape is incredibly diverse, with many actors, countries and even disciplines contributing to novel solutions. There is no one way forward, but many paths, as the short history of quantum computing — marked by ingenuity and persistence — has already shown.

While the future of quantum computing remains uncertain, the one thing we can be sure of is that as quantum computers become more capable, we will find new ways to use them to solve some of the world’s trickiest problems.