Leaps of quantum progress

There is an emerging market for communication, computing and sensing technologies based on the quantum properties of particles and other small systems. The device pictured is a compact quantum light source developed in CQT. (Photo: Aki Honda / CQT, NUS)

| by Associate Professor Alexander Ling |

“Quantum technology” and “record-breaking share price increase” are not terms that have ever been put together, but that was the news in July 2020 when the Chinese company QuantumCTek launched on Shanghai’s exchange. 

The company, which offers quantum-secure communication technology, saw prices of its newly issued shares rise over nine times on its first day of trading breaking records. It rose further before settling down, but is still trading at more than seven times the initial offering price. 

Of course, timing is everything and this takes place against the backdrop of a bull run in Chinese stock markets; nevertheless, it is striking that a quantum technology company is in a position to set this benchmark. It is also an indicator of the scientific progress that has been achieved since the field began almost four decades ago. Today, numerous countries and regions have increased funding for what has become a strategic technology sector. Over the last few months, both Australia and the United States have announced national strategies for developing quantum technology in anticipation of the potential applications.

In the CQT lab of Assistant Professor Dzmitry Matsukevich (left), researchers are developing quantum computers based on trapped ions, processing and storing information in individual, charged atoms

Quantum technologies are a convergence of physics and computer science. Scientists use the physical models of small systems such as atoms, particles of light or supercooled electrical circuits to store and manipulate information in a fundamentally new way. Prominent examples are technologies for secure communication, commercialised by companies like QuantumCTek, and quantum computers. 

While Singapore has yet to see a quantum technology IPO, a few startups have already begun operations here. In June, a company called Horizon Quantum Computing founded by one of my former colleagues announced a funding round led by Sequoia Capital India that brought their financing so far to S$4.5 million. The company has a mission to democratise the development of software for quantum computers.  

Quantum computers have come to public attention over the past few years as large corporations, including Google and IBM, as well as university startups, have ramped up efforts to build them. 

These efforts are not about building just a better version of present computers. Today’s computers are like an automated and sped up abacus. Instead, a quantum computer will manipulate information using the most exacting model of reality humans have ever constructed – quantum physics.  

The building block of quantum information is an abstract concept known as a “qubit”. Qubits can have myriad physical manifestations (such as the atoms, photons or electrical circuits mentioned above), but all qubits have the same unique feature - they can store 0 and 1 at the same time with varying weights between the two outcomes. Scientists call this state “superposition”.  In contrast, present day computers can only store data as lists of 0s and 1s, with each bit fixed as either 0 or 1, and it turns out that this is a fundamental roadblock towards more powerful computing.

In the 1990s, scientists discovered that carefully controlled interference in qubits can quickly solve some mathematical problems that are tricky for conventional computers. The matter would probably have rested there as an erudite problem for scholars and scientists to puzzle over – except that the solved problems map to some practical challenges. We now believe that quantum computers can be applied to search for new drugs and materials, as well as solve difficult optimisation problems. 

So far quantum computers are too noisy and have too few qubits to solve truly relevant problems, but the quantum community is hopeful about achieving computers with more qubits and better performance in the next decades. Companies across the economic spectrum including automotive, energy, chemicals and finance are forming consortiums to explore the technology. 

However, quantum computers also pose a challenge to society. They turn out to be excellent solvers of the math problems used in existing encryption systems. This means that whoever is in possession of a full-fledged quantum computer could break much of the encryption used today in a relatively short time. For long-term privacy, say of health records or government communications, we need something different. One solution can be the transmission of qubits themselves. Sending superpositions of 0s and 1s can help two parties to generate a secure encryption key that is impervious even to quantum computers. 

China has implemented such quantum secure communication along thousands of kilometres of optical fibre, and South Korea’s SK Telecom is planning to use the technology to secure sections of its 5G network. In Singapore, the NUS-Singtel Cyber Security R&D Laboratory has successfully tested quantum communication on Singapore’s fiber network. More domestic deployments are being planned.

There is an emerging market for communication, computing and sensing technologies based on the quantum properties of particles and other small systems. The device pictured is a compact quantum light source developed in CQT

My team and I have also been thinking ahead about how Singapore could make quantum secure connections to other parts of the world. Practically, we can only send quantum keys through fiber over distances of some 100 kilometres or so before we lose too many qubits for the technique to work. This is because the fibre material absorbs or scatters the qubits. 

The distance limits could be overcome using satellites to send qubits between parties further apart. China has already shown this is possible with a satellite called Micius, weighing some 630 kilograms. 

My team is working to miniaturise quantum communication technology for space, so that launching a global constellation of satellites, as we would need to establish global collections, would be cost-effective. In June, we announced the successful operation of our SpooQy-1 nanosatellite. Built at the Centre for Quantum Technologies (CQT) and launched in 2019 via the International Space Station, SpooQy-1 is just 30 centimetres long and weighs only 2.6 kilograms. Our data shows that the quantum device on the nanosatellite works as we had hoped, creating coupled pairs of light qubits. Next, we are working on plans for another nanosatellite that can send qubits from space to ground.

Some of this technology has spun-off into the local startup SpeQtral. They raised around S$2.6 million seed funding last year and are working with a broad range of companies to bring quantum secure communications to the region. 

There is still much work to be done to realise the potential of quantum technologies, but early investments at the national and commercial level can reap early benefits. The progress in the next two decades may exceed what we can imagine now.

About the author

Dr Alexander Ling is a Principal Investigator at the Centre for Quantum Technologies and Associate Professor at the NUS Faculty of Science’s Department of Physics.