Quantum computers have been reserved for scientists for years. However, recent advances are driving this potentially revolutionary technology towards practical applications.
At this month's Q2B conference, quantum computer makers Google, IBM, Honeywell, IonQ, and Xanadu outlined specific steps they expect to take by 2024 to further advance their machines on the path to commercial feasibility. These successes include increasing the size, performance, and reliability of quantum computers. Private sector spending on quantum computing products and services will more than triple to $ 250 million in 2024, compared to $ 250 million in 2019, according to a forecast by Hyperion Research.
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"We are in the early industrial age of the quantum computer," said Seth Lloyd, an MIT professor who helped found the field in the 1990s. He says the "enormous advances" are comparable to the early use of steam engines to power factories, ships and trains.
A snappy breakthrough is the advancement towards error correction, with which quantum computers should perform sustainable calculations rather than fleeting bursts of work. This improvement comes by overcoming a fundamental barrier with qubits, the basic elements of storing and processing data in a quantum computer. Qubits are easily disturbed by external forces, but the error correction is intended to overcome the delicacy of individual qubits. Larger machines with many more qubits are needed, but quantum computer manufacturers are also seeing progress there.
If quantum computer manufacturers are successful, error correction could help the industry deliver on their promise to dramatically improve the performance of traditional processors on some important problems. Quantum computers will not replace classic machines, which are also confronted with manufacturing difficulties and rising costs. However, they could go beyond today's boundaries to develop new solar panels, reduce aircraft fuel consumption, accelerate artificial intelligence, improve financial investments, and reduce delivery costs.
Quantum computers go beyond ones and zeros
Traditional computers store information as bits - ones or zeros - and perform calculations using tiny electronic data processing components called transistors. In contrast, the qubits of quantum computers can store a combination of one and zero at the same time thanks to a quantum physical phenomenon called overlay. Qubits can be linked together by entanglement, another phenomenon in quantum physics.
Quantum computing involves a series of manipulations on qubits states. These manipulations are called quantum gates, and a sequence of gate manipulations is called a circuit. When gate manipulations are added, a circuit becomes "deeper" and can perform more complex quantum computations.
As the number of qubits increases, the computing problem that is within reach is also exponentially increased. Adding a single qubit doubles the possible computational effort. Adding two quadruples, adding three octuples, and so on.
Computer scientists are enthusiastic about these advances, because although today's machines have a few dozen qubits, tomorrow's machines will have thousands, then millions.
Picky qubits derail calculations
Quantum computer manufacturers are all working on different methods to create more stable qubits in order to create a stronger foundation for the qubits themselves and their interconnection. Disturbances that either derail the calculation.
While manufacturers of conventional silicon chips have committed themselves to one approach, quantum computer manufacturers are looking for very different options for their qubits.
Google and IBM use superconducting circuits that have cooled to near zero and are colder than space. Honeywell's ion trap design makes qubits from electrically charged ytterbium atoms. Intel's qubits are individual electrons that are characterized by a quantum mechanical property called spin. Xanadu uses photons and its quantum processors operate at room temperature.
With the error correction, quantum computing remains on course
A strong foundation is good, but error correction is still important to overcome the flaky nature of individual qubits. The main idea for error correction is to merge several qubits into a single "logical" qubit whose state lasts longer. Eric Lucero, who runs Google's quantum computing service, calls them "perfect qubits forever". Error correction is the basis for what is known as a fault-tolerant quantum computer.
A logical qubit can take up to 1,000 physical qubits, and serious quantum computing, like Shor's algorithm, which is used to crack today's encryption, requires thousands of logical qubits. IonQ is hoping its approach will only require 13 physical qubits for a logical qubit, IonQ chief scientist and co-founder Chris Monroe said in the second quarter.
The approach moves from theoretical to practical.
"We have the technology today," said Lucero. He expects Google to have its first logical qubits in 2023 and 1,000 of them by the end of the decade.
More and better qubits
The error correction is a great incentive to increase the qubit count.
IBM plans to outperform its current 65-qubit Hummingbird with a 127-qubit eagle by next year and a 433-qubit Osprey in 2022. In 2023, the 1,121-qubit Condor will be "a major turning point" in making quantum computers more useful to algorithms, said Anthony Annunziata, director of the IBM Q Network
Xanadu now has 24 qubits and is expecting a 40-qubit chip this year, says Zachary Vernon, the company's hardware chief. In the coming years, he predicts that the number of qubits should double every six to 12 months.
Useful quantum computers
Although researchers are careful to avoid promises of breakthroughs, quantum computers could come in handy before the error correction hits. IBM's quantum customers today include JPMorgan, ExxonMobil, Mitsubishi Chemical, Daimler, Delta and Boeing.
Some of these customers are interested in designing materials from the molecule up - one of the first ideas described by the famous physicist Richard Feynman in pioneering thinking about quantum computers. The hope is for breakthroughs such as more efficient solar modules, Batteries that store more energy or fertilizer production that does not require as much electricity.
The European aerospace giant Airbus has an extensive program, said Marc Fischer, senior vice president of flight physics for the company, in the second quarter. It's about studying quantum computers to improve aircraft aerodynamics, reduce aircraft fuel consumption during ascent, load aircraft more efficiently, and design wings with factors that are difficult to calculate with classic computers, he said.
Honeywell sees the use of quantum computers for its own businesses such as chemical design, warehouse automation, and aerospace. "Honeywell expects to be our biggest and best customer," said Tony Uttley, president of Honeywell Quantum Solutions.
One of the most optimistic voices is Eric Schmidt, who in his previous role as chief executive and executive chairman of Google approved the company's long-term quantum computing program. This work resulted in the "Quantum Superiority" experiment last year, which showed that quantum computers can outperform classical computers for at least one narrow (if not practical) computational task.
"We know this stuff will happen in six to eight years," said Schmidt. "It'll be amazing when it happens."
