In 2019, researchers at Google claimed that their quantum computer, Sycamore, carried out a calculation in three minutes 20 seconds that would take world’s most powerful supercomputer 10,000 years to perform. Some hailed Sycamore’s quantum supremacy over classical machines as a Sputnik moment, saying it was a significant advance in fields like biotechnology and artificial intelligence promised by quantum. Others, like IBM’s quantum researchers, were more skeptical, saying that their supercomputers could already perform the same task in a couple of days.

Silicon Valley infighting aside, the hype around Google’s claim of quantum supremacy highlights what some have called a contemporary arms race. Over the last decade, the U.S., China, and European Union have devoted substantial resources to developing quantum-enabled intelligence and military capabilities. In the U.S., the effort has bipartisan support. In 2019, the Trump administration proposed a nearly 21% increase in quantum information science funding through 2022. The Biden administration has likewise prioritized quantum research in its bipartisan infrastructure investment plan. Meanwhile, the Intelligence Community has named quantum computing as one of five technologies that are key to maintaining the U.S. edge in the coming decade, cementing quantum as a prominent feature in the U.S. national security agenda. As the quantum race intensifies, it is important for policymakers to understand the fundamentals of quantum computers, their potential advantages, and the challenges for national security.

What are Quantum Computers?

Quantum computers mimic the behavior of atoms and subatomic particles to drastically increase processing speed. These particles can exist in several states simultaneously, a puzzling phenomenon called quantum superposition. Atoms, for example, can be excited, not excited, both, and somewhere in between. Quantum objects also form inextricable bonds, or entangle, with one another and influence each other’s behaviors, even from large distances. Two or more bonded quantum objects creates a delicate ecosystem called a composite quantum system. This means that if one object in the system is disturbed, every object with which it is entangled will also be disturbed.

Quantum computers are life-size representations of composite quantum systems. Whereas classical computers process information by sequentially flipping digital switches representing 0s and 1s, quantum computers use units called qubits that represent multiple values simultaneously. Because they don’t need to process information sequentially, qubits can perform calculations significantly faster than bits, which can only do so using discrete values. Quantum information scientists, then, attempt to entangle as many qubits as possible, and when they are successful, quantum computers’ processing power increases exponentially.

One problem, however, is that disturbances among entangled qubits can cause the whole system to fall apart. The characteristics that make quantum systems powerful also makes them delicate. This phenomenon, which scientists call decoherence, poses significant challenges to the dependability of quantum computers. Today’s qubits are extremely sensitive to environmental disturbances like temperature and dust, and disruptions to any part of a composite system can cascade across the whole system. Because of this fragility, the current coherence time – the amount of time a qubit can store memory before succumbing to decoherence – is less than 1 minute.

Opportunities and Risks for National Security

Because of their sensitivity to environmental disturbances, quantum computers today are highly unstable and must be held in expensive refrigerators cooled to near-absolute zero temperatures. At 70 qubits, today’s machines also fall far short of the one million-qubits needed to make quantum computers commercially viable. Still, some researchers predict that such a milestone could arrive within 10 years, and once matured, these technologies will have a host of battlefield, commercial, and strategic applications.

For one, quantum computing can augment artificial intelligence/machine learning. Quantum technology can process and spot patterns in data more rapidly than classical machines, making quantum AI/ML tools more accurate and scalable. Quantum AI tools, for instance, can provide autonomous weapons and mobile platforms, such as drones, with heightened sensing, navigation, and positioning options in GPS-denied areas. Equipped with quantum AI tools, such systems could also independently alter course to avoid enemy countermeasures. 

Quantum also has the potential to significantly increase the connectivity, security, and speed of the internet. The so-called quantum internet links quantum devices together using entanglement. Scientists in the Netherlands, for example, entangled three one-qubit devices that successfully communicated and stored information in a theoretically unhackable manner. At scale, this architecture, which uses quantum cryptography, could usher in a super-secure communications infrastructure that shields internet-connected devices, including critical infrastructure, from cyberattacks.

Additionally, quantum cryptography and artificial intelligence tools can be combined to improve intelligence collection and analysis. Intelligence services equipped with quantum computers, for example, may be able to break 2048-bit RSA encryption in 8 hours or less, a function that would take the world’s fastest supercomputers around 300 trillion years to complete with brute-force methods. Quantum computers would probably need around 20-million qubits to perform this task, but based on the current trajectory of advances in quantum, such machines may be available within 25 years. Quantum artificial intelligence tools would then enable analysts to sort through and make sense of the hordes of data made available by quantum decryption.

That said, adversarial use of quantum computers poses several risks to national security, especially if advances in quantum decryption outpace advances in quantum encryption. An adversary with quantum decryption capabilities, for instance, could theoretically access encrypted information with ease, putting most current communications infrastructure at risk of exploitation. For diplomats, this means that communications between them and their foreign counterparts would no longer be secure. For those in the intelligence community, quantum cryptanalysis could expose the U.S.’ deepest state secrets, creating a crisis exponentially worse than the Snowden data leaks. And, quantum cryptanalysis could enable adversaries to decode valuable battlefield communications, significantly undermining military strategy.

States will also likely compete for control over the quantum internet. The traditional internet was founded on a set of common standards, principles, and protocols. In the nascence of the quantum internet, however, allied states have been reluctant to collaborate on quantum research, and adversaries have not agreed on shared quantum age governance principles. In a time when governments increasingly seek to regulate the flow of information and localize data within their borders, quantum research siloes could speed up the shift toward the formation of several “mini-internets” that states control for their own interest.

Challenges for Policymakers

The U.S. government has begun taking measures to protect information from quantum cryptanalysis and grapple with questions about global governance of quantum technologies. The National Institute of Standards and Technology is compiling general use guidance for post-quantum cryptography, and Congress enacted the National Quantum Initiative Act in 2018 to harmonize federal efforts around QIS. These efforts form the basis of a domestic quantum strategy and could ease the government and military into the quantum age by alleviating institutional hurdles to adoption. Diplomats might also include quantum in discussions of rules and norms around other emerging technologies like AI. Existing fora, such as the International Telecommunication Union’s AI for Good initiative, could provide models for facilitating intergovernmental conversations about quantum governance. Yet national and international efforts will only go so far, because private sector investment is driving quantum research. Today, Google and IBM are competing over press coverage and processing speeds. Efforts to control future applications will require their cooperation.

About the Author: 

Harrison Brooks is a current graduate student in the School of International Service's Global Governance, Politics, and Security program. He is specializing in global security, intelligence, and cybersecurity. Harrison is interested in exploring the potential implications of artificial intelligence and quantum computing for intelligence, warfare, and global competition.

*THE VIEWS EXPRESSED HERE ARE STRICTLY THOSE OF THE AUTHOR AND DO NOT NECESSARILY REPRESENT THOSE OF THE CENTER OR ANY OTHER PERSON OR ENTITY AT AMERICAN UNIVERSITY.