Quantum Computing Remains Tantalizingly Out of Reach

Stephen DeAngelis

August 23, 2019

Some companies are touting their quantum computing capabilities; however, their offerings are not the generalized, programmable quantum computers for which most researchers are striving. Almost weekly there are reports of new breakthroughs that support various components of quantum computing including new algorithms, new qubits, new theories, etc. Each breakthrough promises to bring quantum computing one step closer to reality. For example, John Loeffler (@thisdotjohn) recently reported, “In a new report in Quanta Magazine by Kevin Hartnett, Hartmut Neven, the director of Google’s Quantum Artificial Intelligence Lab, reveals that the growth in power with each new improvement to Google’s best quantum processor is unlike anything found in nature. It’s growing at not just an exponential rate, like in Moore’s Law, but at a doubly-exponential rate, meaning we may be mere months away from the beginning of the practical quantum computing era.”[1] Other prognosticators have predicted a practical quantum computer will be developed with the next five years. Still others predict, “The large, error-correcting quantum computers envisioned today could be decades away.”[2] Conversely, Mark Jones (@MJ_TechHQ) predicts, “Accessible quantum computing is just around the corner.”[3] To date, the corner around which quantum computing lurks is at the end of a never-ending hallway like those found in a horror films.

Quantum computers are worth the wait

Although it must be frustrating for researchers to be so close yet so far from creating a practical quantum computer, they know it’s worth all the time and effort. Alan Daley (@afdaley) notes, “Quantum computing (QC) offers the possibility of super-fast execution of digital algorithms. QC is not so much a replacement for conventional computers as a replacement for today’s supercomputers.”[4] Po Chi Wu, who teaches entrepreneurship at the School of Business and Management at the Hong Kong University of Science and Technology, asks, “Who cares about quantum computing?”[5] He admits understanding quantum computing is a challenge for most people. After all, quantum computing is based on weird things found only in the quantum world (e.g., superposition — where a qubit can simultaneously be both a 1 and a 0 — and entanglement — something Albert Einstein famously called spooky action at a distance). Wu writes, “In the realm of quantum computing, I see a philosophical conundrum for visionaries. Skeptics of new technology often think: ‘Since I don’t understand it, how can it be good for anything?’ Implicit in this attitude is the assumption that ‘I only see value in what I can understand’. For visionaries, just having the dream already has value. For quantum computing, there naturally is a requirement to create a new language that can accurately describe how QC works and what it can do.” He continues:

“A quantum computer, however, is designed to work with ‘probability states,’ which are, by definition, abstract concepts that cannot be detected by or mapped to specific physical states. Can you feel the cloud of confusion creeping into your mind after reading just this brief description? What is a probability state and what does it represent? How does that reflect physical reality? These questions have been asked and answered for quantum mechanics. Still, most people have no feel for what these abstract concepts mean in everyday life. … The key value of QC is not just to accelerate tasks that are currently possible (but impractical) by classical computing. … What is most interesting is being able to do what classical computers … can’t do, due to inherent technological limitations of man and machine.”

The Singularity Hub staff explains, “Quantum computers calculate using quantum bits, known as qubits. Qubits can be both 1 and 0 simultaneously — meaning they can perform two calculations at once. This is only possible on the smallest scales, where the laws of quantum physics hold sway, and makes for massively faster computing compared to digital computers.”[6] James Norman explains, “Quantum computers can be game changers because they can solve important problems no existing computer can. While conventional computing scales linearly, QC scales exponentially when adding new bits. Exponential scaling always wins, and it’s never close.”[7]

How close are we getting?

Most researchers believe we are tantalizingly close to building a practical, programmable quantum computer. One of the greatest challenges is creating a fault-tolerant qubit. Because quantum computers work at the quantum level, qubits can easily be knocked out of their superposition state by stray elements. For that reason, quantum computers are built with extensive shielding and operate at temperatures near absolute zero. The University of California, Riverside, announced a step towards creating a better qubit. The article notes, “A joint team of scientists at the University of California, Riverside, and the Massachusetts Institute of Technology is getting closer to confirming the existence of an exotic quantum particle called Majorana fermion, crucial for fault-tolerant quantum computing — the kind of quantum computing that addresses errors during its operation. … Majorana fermions are one of the most sought-after objects in quantum physics because they are their own antiparticles, they can split the quantum state of an electron in half, and they follow different statistics compared to electrons. Though many have claimed to have identified them, scientists still cannot confirm their exotic quantum nature. The UCR-MIT team overcame the challenge by developing a new heterostructure material system, based on gold, that could be potentially used to demonstrate the existence and quantum nature of Majorana fermions.”[8]

Admittedly, that doesn’t make it sound like a quantum computer is going to be created any time soon. Nevertheless, progress continues to be made. Australia’s Daily Excelsior reports, “In a major breakthrough in quantum computing, a team of Australian scientists has built a super-fast version of the central building block of a quantum computer, which has the potential to solve complex problems at a 200 times faster rate. … According to a paper published in Nature journal, physicist Prof Michelle Simmons and her team at the University of New South Wales have built the first two-qubit gate between atom qubits in silicon, a technology which is capable of completing an operation at a 200 times faster rate than previously achieved at 0.8 nanoseconds. A two-qubit gate is the central building block of any quantum computer.”[9]

Concluding thoughts

Even if a practical, universal quantum computer is built, it won’t be cheap. And Loeffler notes, “Much of the core theoretical-computer science of quantum computing is still being written and debated.” So why all the fuss? The Daily Excelsior staff writes, “Experts predict that the advent of quantum supremacy will herald revolutionary breakthroughs in nearly every scientific field, including chemistry, astrophysics, medicine, security and communications. More advanced quantum computers will also have the potential to help scientists unlock the mysteries of the cosmos, such as how the universe came to be and whether life exists outside earth.” You can sense the anticipation researchers have to make quantum computing a reality. Stewart Allen, COO of quantum computing startup IonQ, told Jones, “It’s an event horizon, we don’t know what it looks like until we travel there.” We just don’t know when that will be.

Footnotes
[1] John Loeffler, “Google’s Quantum Processor May Achieve Quantum Supremacy in Months,” Interesting Engineering, 23 June 2019.
[2] Virginia Tech, “Virginia Tech Researchers Lead Breakthrough in Quantum Computing,” HPC Wire, 26 July 2019.
[3] Mark Jones, “Accessible quantum computing is just around the corner,” Tech Headquarters, 23 July 2019.
[4] Alan Daley, “The Future Technological Advances of Quantum Computing – It’s Worth the Wait,” The American Consumer Institute, 21 June 2019.
[5] Po Chi Wu, “Who Cares About Quantum Computing?Psychology Today, 23 July 2019.
[6] Staff, “Why Quantum Computers Will Be Exponentially Faster Than Digital Computers,” Singularity Hub, 18 September 2017.
[7] James Norman, “Quantum Computing Will Revolutionize Data Analysis. Maybe Soon,” Seeking Alpha, 14 March 2018.
[8] University of California, Riverside, “New material shows high potential for quantum computing,” Phys.org, 28 June 2019.
[9] Staff, “Australian scientists built super-fast quantum computer,” Daily Excelsior, 22 July 2019.