This is Part1 of a two-part series. You can read Part 2 here.
Quantum technology, previously uncharted territory, it is increasingly becoming an area of interest for organisations and businesses to explore the capabilities of this technology.
To provide that opportunity for our readers to gain better insights into this technology, OpenGov had the honour of interviewing Nana Liu, currently an Assistant Professor at the John Hopcroft Center for Computer Science in Shanghai Jiao Tong University.
Nana received her doctorate in 2016 from the University of Oxford as a Clarendon Scholar.
She was a Postdoctoral Research Fellow at the Centre for Quantum Technologies in the National University of Singapore and the Singapore University for Technology and Design.
Nana is also one of EmTechAsia’s Innovators Under 35 for 2019.
Her focus is on employing quantum resources for both quantum computation and quantum sensing.
Nana’s research lies at the interface between quantum computing, security and machine learning, which will be useful in building a future quantum internet.
What is Quantum technology?
Nana broke it down and explained the key concepts and features unique to quantum technologies. She said that the proposed advantageous functionality of quantum technologies arises from quantum mechanical behaviour of matter that cannot be explained by classical physics alone.
Quantum mechanics is the best-tested theory of physics to date and contains all of classical physics. However, some of its most counter-intuitive behaviour can only become more apparent on very small scales, like the scale of atoms.
For instance, quantum mechanics predicts that all matter, whether on the scale of electrons or baseballs, have a wave-like description. However, the wavelength for baseballs is so small that they are much less detectable than that of electrons.
Quantum technologies can exploit such counter-intuitive behaviour of quantum matter for tasks like computation and sensing.
For example, when the wave-like nature of quantum matter becomes dominant, behaviour like interference of waves can be exploited. Waves can both constructively and destructively interfere.
When this feature is cleverly used in a computational algorithm, this allows the incorrect answers to the computation to appear less often.
This can lead to `speed-ups’ in certain algorithms on quantum devices when compared to known classical algorithms.
Aspects of Quantum Technology
Quantum Cryptography
This use of quantum technology allows for secure communication amongst people.
Classical physics allows for information to be cloned (photocopied exactly).
An unknown (private) quantum message in comparison cannot be copied completely. When a hacker is trying to tap into a conversation `trying to copy it’, it will disrupt the line and those involved in the conversation will know about it.
Nana shared on how China has made one such innovation in this field. The Micius satellite launched in 2016 had set up its first intercontinental quantum cryptography service.
A secure videoconference between Europe and China was set up to test the service. It proved that the laws of physics governed and determined the security of the videoconference.
This was achieved with quantum cryptography using a one-time pad which is made up of a set of random numbers that form a key. This key can only be used between the two communicators who will use it encode and decode a message.
Nana said that quantum cryptography done in this way is provably secure.
Quantum Computing
This uses quantum mechanics for encoding and processing information in a new way. Nana said that quantum computing algorithms can be designed in a different way to classical computing.
However, is no definite proof that it can be exponentially faster than classical computing. “It is just a belief at the moment that perhaps some algorithms in some limited regimes can achieve this, but perhaps at a cost of other resources required,” she said.
Quantum supremacy
Nana explained that this technological process involves using a quantum device to perform a quantum algorithm that outperforms the current best classical device. Recently, Google demonstrated an algorithm, called random circuit sampling, on their 53-qubit device Sycamore. It involves using a quantum device to perform a sequence of random quantum operations. The claim is that the resulting distribution of numbers after measuring the output on the quantum device can be calculated much faster than on a classical device.
Nana said that while this is an important step, the technology is still at the very beginning. The hope is that, even with current noisy and relatively small quantum devices, useful applications for quantum algorithms that can be comparable or better than state-of-the-art classical devices can be found.
Quantum metrology
Another area where quantum technologies can offer quantum advantage is in sensing and there is theoretical proof of this advantage. Nana said that the process uses quantum matter to probe materials and measure certain properties of these materials more accurately with fewer resources.
For example, this allows imaging to be done, using light enhanced by quantum properties. One such property is that of quantum entanglement. Here, light in different locations can have a correlation with each other that is much stronger than can be achieved classically. In these cases, more accuracy in imaging can be achieved with less light.
Nana said that experimentally, this is currently at the proof-of-principle stage. Real-life deployment of these technologies still requires more work to deal with noise and losses