Imagine a sensor that could instantly detect nuclear submarines deep underwater, a supercomputer that can break the strongest encryption in the blink of an eye, or a worldwide satellite network of theoretically unbreakable communications.
These are just a few of the capabilities promised by quantum physics, a century-old science, which found that particles have unique and unexpected properties at the smallest scale. Scientists have long theorized that these properties could revolutionize computing, sensing and a host of other technologies.
Today, these theoretical ideas appear to be on the brink of spurring a revolution in quantum technologies, which has the potential to reshape the way that countries think about defense and national security.
Now, the race is on between U.S. agencies like the NSA, which is reportedly building a next-generation quantum computer capable of breaking classical cyber encryption, and potential adversaries like China, which launched the world’s first quantum communications satellite last year.
The crux of quantum mechanics is focused around two unique properties observed at the quantum scale. The first, superposition, allows particles at the quantum level to exist in two different places at once until measured. The famous thought experiment of Schrodinger’s cat, in which a cat is placed in a box with a flask of poison, a tiny radioactive source, and a Geiger counter, demonstrates this paradoxical state. If the Geiger counter senses radioactivity – in this case, a random subatomic event – it will trigger a device to break the flask of poison. However, since this event is random, the cat can be considered to be both alive and dead at the same time until someone takes a measurement by looking in the box.
The quantum property of entanglement is similarly strange. Scientists have found and proven that certain particles can become “entangled,” and thus interact with each other, even at great distances, in ways that cannot be explained by classical physics. Albert Einstein famously described this phenomenon as “spooky action at a distance” in his arguments critical of the theory.
The initial discovery of these and other bizarre quantum interactions were “a great surprise…but it wasn’t until more recently that we focused on actually controlling these phenomena,” said Dr. Brad Blakestad, quantum computing expert and Program Manager at the Intelligence Advanced Research Projects Activity (IARPA), under the Directorate of National Intelligence.
This recent focus on control has led to a modern race to discover “what applications we can use these different properties for in quantum information tasks, such as quantum sensing or quantum computing.”
By their nature, quantum systems are highly sensitive to interference or “noise” from their surrounding environment, and the difficulty of isolating quantum particles from that noise has been one of the most significant engineering stumbling blocks to developing real world quantum applications. However, this sensitivity to disruption also means that quantum systems could provide next-generation sensing capabilities that far outstrip current technology.
For instance, the lab at the National Institute of Standards and Technology (NIST) has been developing increasingly precise atomic clocks since the 1950s – probably the first quantum device. Now, these clocks have become so precise that they can actually sense the gravitational effect on time, which moves slightly slower the closer one gets to the Earth’s gravitational center.
This gravity sensor can not only provide ultra-accurate measurements of altitude, it could also detect gravitational anomalies underground or underwater, such as a hidden underground nuclear facility in North Korea, or a Russian nuclear submarine. This gravitational sensor might also provide the foundation for new and more accurate navigation systems, possibly replacing current geospatial navigational tools, such as GPS. New systems could be developed to more accurately detect anomalies in the electromagnetic spectrum, opening up a world of new possibilities for military and civilian applications.
Quantum applications in the cyber realm have been somewhat more difficult to develop and test.
To make quantum computing work, “you have to isolate your systems very carefully, you have to cool them to unimaginable cold temperatures and try to isolate them from every source of noise,” said Dr. Stephen Jordan, a quantum physicist at NIST. In addition, Blakestad notes that “superpositions don’t stick around once you measure them,” which makes it very difficult unlock the computing power of quantum systems.
However, if scientists can overcome these and other hurdles, quantum computers should theoretically be able to work at extreme speeds. In particular, these systems could vastly improve the ability of computers to calculate numbers into their prime factors.
“That,” says Jordan, “is of great significance to security because if you could do that you could break all of the commonly used, widely deployed cryptographic systems.”
Fears over this coming disruption of cryptography, which underlies much of existing global cybersecurity practices, has led to a race for next-generation cryptography that can withstand the quantum revolution. In fact, NIST has warned that cyber systems will need to switch over to post-quantum encryption by 2025 in order to stay ahead of this threat.
Some of this race is focused on creating new cryptography, which is complicated enough to withstand a quantum attack. But another avenue of research is focused on creating a whole new class of unbreakable quantum communications. One such method, quantum-key distribution, utilizes the measurement problem of quantum mechanics by shooting polarized light particles between a sender and receiver. If someone tries to intercept – and thus measure – this transmission, the randomness of the quantum signal will be disrupted, alerting the communicators that someone is listening in.
On the ground, this quantum-key distribution method has only been used along optical fibers and limited to about 100 kilometers in range. However, China launched the world’s first quantum satellite, Micius, into orbit last year, where it can transmit such encrypted messages much farther through space. This could be the first building block of a global network of unbreakable encrypted communications.
China is not the only actor outside the United States investing heavily in quantum technology. The European Union, Russia, Japan, and many others are funneling public funds into quantum research, while international corporations from Google to major automakers invest millions into quantum R&D and patent applications.
Practical quantum systems may still be years away, but U.S. agencies are rushing to get ahead of this technological revolution. In 2016, the National Security Agency warned that it “must act now” to prevent quantum computing from undermining current encryption. Meanwhile, the NSA is reportedly working on its own quantum computer capable of penetrating currently unhackable systems.
Practically feasible quantum systems are now just over the horizon, as researchers, private industry, and governments are racing to prepare for and lead this next technological revolution.
Fritz Lodge is a Middle East and international economics analyst at The Cipher Brief. Follow him on Twitter @FritzLodge.