Quick background on Quantum Theory
Quantum theory is the branch of science that studies nature on the smallest scale. The field spans the physical observation of atomic and subatomic particles (like electrons and photons), as well as the philosophical implications of theories that imagine the possibility of parallel universes.
Early quantum pioneers include Albert Einstein and Erwin Schrödinger — responsible for the famous paradox about a cat that could be alive and dead at the same time. American Richard Feynman shared the 1965 Nobel Prize in Physics for his contributions toward developing an understanding of quantum mechanics, despite his quip that “nobody understands quantum mechanics.”
In 1981, Feynman coined the term “quantum computers,” challenging the next generation of scientists to pursue practical applications of quantum theory. Scientist Peter Shor captured the science world’s attention in 1994, by demonstrating how quantum computers could easily factor large numbers — possibly thwarting the dominant systems for data security. In 2007, Canada’s D-Wave announced plans for the first-ever commercially viable quantum computer. Over the last decade, both academic institutions and corporate research centres have contributed to a substantial development of theoretical knowledge and practical engineering required to launch the quantum computing revolution.
What is Quantum Computing?
In simplest terms, a quantum computer is a device that uses quantum theory to process information. Compared to the computers we use every day — often referred to as “classical computers” — quantum computers can perform far more complicated operations in a much shorter period of time.
A quantum computer is NOT just a more powerful version of a classical computer. In fact, quantum computers and classical computers differ in a number of significant ways:
- physical construction and materials
- theoretical framework for processing information
- methods for programming
The Limits with Bits
Today’s computers use binary, a system of representing information with a pattern of zeros and ones. Each individual zero and one is called a bit (short for “binary digit”). Computer programmers use sequences of 8 bits to indicate numbers, letters, and symbols. Using binary code, 01010100 represents an uppercase “T” and 01001111 represents an uppercase “O.” (As such, 01010100 01001111 would communicate “TO” — a nickname for the city of Toronto).
By stringing together long sequences of bits, computers can perform calculations. Although binary systems are highly effective for solving some types of problems, classical computers can struggle when faced with complex operations. The term “intractable problems” refers to advanced calculations that would take classical computers too long to solve — thousands of years, in some cases.
The Quirkiness of the Quantum Realm
In the natural world, humans can readily observe certain phenomena like gravity and inertia. In the quantum realm, on the other hand, subatomic particles behave in quirky and counterintuitive ways. Even Albert Einstein described some quantum properties as “spooky actions.”
As a pop culture example, several movies from the Marvel Cinematic Universe explored the quantum realm: Ant-Man and Wasp shrunk down to subatomic size and the Avengers entered parallel universes. (Of course, Hollywood took liberties with scientific facts).
Qubits, Superposition, and Entanglement
Researchers are trying to develop computers that can harness the peculiar properties of the quantum realm. At the fundamental level, quantum computers use qubits (short for “quantum binary digits”). A qubit, just like a bit, can store data using the digits 0 and 1. In contrast to bits, though, qubits can also represent multiple combinations of 0 and 1 at the same time.
The ability of qubits to simultaneously exist in multiple states is difficult for many people to conceptualize. Imagine, for a moment, flipping a coin. You will end up with one of two outcomes: heads or tails. But how would you describe the coin during its time in the air, when it is rapidly spinning? Your eye can perceive both sides of the coin at the same time.
Here is a (very) rough analogy: classical computers can only process a coin’s final position, heads or tails (a binary equivalent to 0 and 1). Quantum computers — in this analogy — could also process a coin during its time in the air, identifying the probability that the coin will land on its heads side or tails side. Quantum researchers refer to qubits’ ability to simultaneously exist in multiple states as superposition.
Another property of the quantum realm — entanglement — might help decrease the time that computers require to solve complex calculations. A pair of qubits in superposition can become “entangled,” so that they share a special connection. Scientists have discovered that impacting one entangled qubit will instantly change the state of its partner — even across significant distances. The concept of entanglement offers incredible potential for instantaneous and secure communications across the globe.
The Power of Quantum Computing
Classical computers typically perform one operation at a time. By exploiting quantum properties, quantum computers can simultaneously process multiple tasks.
Imagine using a computer to solve a maze. A classical computer would test every possible solution — one at a time — before identifying the correct path. Quantum computers would analyze the entirety of the maze before highlighting the optimal solution.
Practical Applications
Beyond solving mazes, quantum computers could apply its route optimization power to several real-world contexts, such as supply chain logistics and fleet operation for delivery vehicles.
At the start of 2020, the capabilities of quantum computers are still hypothetical, rather than demonstrable. Scientists have envisioned many possible applications for quantum computers in several areas.
Security offers the most directly applicable uses for quantum theory.
- Cryptography: our standard RSA encryption system relies on the multiplication of prime numbers, something quantum computers could easily identify.
- Cybersecurity: quantum-proof algorithms could protect data against attacks from quantum computers.
- Communications: with quantum key distribution, two parties can share a secure line of communication. (In January 2020, China developed the world’s first quantum satellite station).
In chemistry, quantum computers might not only deepen scientists’ understanding of molecules, but also facilitate the engineering of customized compounds and proteins.
- Physical chemistry: improvements in batteries could reduce cost and environmental impact.
- Biochemistry: engineered medications could increase effectiveness and decrease side effects.
- Health care: advances in DNA gene sequencing could lead to personalized cancer treatments.
Fields involving statistical models could see significant developments in short periods of time.
- Artificial intelligence: faster data analysis could enhance the comprehension of AI systems.
- Computer science: by processing more than one piece of information at a time, quantum computers could facilitate quicker and more robust search functions.
- Finance: simulations of market performance could be performed more quickly and accurately.
Quantum computers might be able to perform types of qualitative analyses that bewilder classical computers.
- Natural language: communicating instructions to computers with natural language, instead of coding languages.
- Reading comprehension: with greater capacity to analyze written text, quantum computers could highlight the key ideas from news articles and other literary sources.
- Image recognition: by efficiently reviewing image archives, quantum computers could identify any elements that appear in visual materials like photographs.
Obstacles in Quantum
In recent years, researchers have taken huge strides — a quantum leap, you might say — in the advancement of theoretical and technological progress. Nevertheless, significant obstacles stand in the way of widespread access to quantum computers:
Qubits: scientists are still developing reliable processes for creating and controlling qubits, and in the quantity required for useful applications. (Current methods include laser beams, electromagnetic fields, radio waves, and experimental techniques called ion traps and optical cavities).
Fragility and noise: to operate quantum computers with any type of efficient practicality (i.e., not just experiments), researchers need to hold qubits in a state of superposition long enough to observe their activity. Unfortunately, qubits are extremely delicate. Temperature changes, physical vibrations, or other environmental disturbances can knock qubits out of superposition. These disruptions — referred to as noise — introduce errors to the computer’s processes. To reduce the amount of noise, research centres isolate their quantum computers in a number of ways: electromagnetic shielding, vacuum chambers, and supercooled temperatures.
Human capacity: as a relatively nascent field, quantum computing lacks a sufficient pool of highly skilled researchers, engineers, and technicians. Universities and corporate research centres are introducing new training programs, but years might pass before the quantum labour shortage is resolved.
The Quantum Race
Many established technology companies are devoting substantial attention to the development of quantum computers. In particular, IBM and Google have engaged in a high-profile competition for dominance in the field; other major players include Microsoft, Intel, and Toshiba. Quantum’s vast potential has piqued the interest of many tech-minded entrepreneurs. Startups with quantum-focused projects have proliferated; most notably, Vancouver’s D-Wave and Silicon Valley-based Rigetti Computing have attracted an international reputation for their achievements. In China, e-commerce giant Alibaba has invested $15 billion (USD) for quantum-related research, with a strong focus on cloud computing and telecommunications.
During the space race, the United States and Soviet Union sought to demonstrate the superiority of their technological (and political) capabilities. Quantum research is evoking similar exhibitions of national pride, across a greater number of countries. In 2016, the EU announced the Quantum Flagship program: they committed €1 billion to a range of projects that would advance quantum technologies. Despite the current political polarization in the US, the Senate unanimously approved the 2018 National Quantum Initiative. The NQIA promised $1.3 billion (USD) in funding for quantum innovation, as well as the establishment of multiple research centres. China is pouring resources into quantum applications. In 2017, the country built the world’s largest quantum research facility; by the middle of 2020, China plans to open the National Laboratory for Quantum Information Sciences — a project rumoured to cost $10 billion (USD).
To learn more about quantum in Canada, check out this post.
