Quantum Technologies Suit Up for the Battlefield

The U.S. Army soldier proceeds methodically, picking his way through dense vegetative growth as he traverses a battlefield that geologically is ages old, but technologically is years in the future. With the enemy rendering satellite-borne GPS signals ineffective, the soldier resorts to his internal position-location unit that pinpoints his spot to the meter. His external sensor suite alerts him to the presence of enemy air and ground forces, but they are far enough away to be of no consequence yet. That raises suspicions in his mind, as they seem to have left the soldier’s area strangely undefended—even unattended.

Turning to his ground scanner, he discovers that he is alone only above the surface of the Earth. His gravitational sensors have detected a fortified tunnel structure just ahead of him that stretches for some distance forward and to the sides. It seems to be built with concrete reinforced by metal bars, and by the way it is constructed, it probably is concealing a large number of enemy troops and their materiel.

Not wanting to allow them to emerge and gain the upper hand over him, he opts to send an encrypted message back to headquarters, confident that it cannot be broken. Using his portable precision navigation system, he is able to provide the exact coordinates for the mystery bunker, along with his own position. Then, he steps back as a team of robotic unmanned aerial vehicles attack the bunker with precision munitions that penetrate the ground and lay waste to whatever is beneath. When the dust settles, he is unscathed. He does, however, need to find a new way forward around the rubble that once constituted a hidden enemy base.

Every action conducted by this future soldier—except for those driven by his own thought processes—was enabled by quantum technologies deployed throughout the force. These systems currently are the targets of research by the U.S. Army’s Combat Capabilities Development Command (CCDC) Army Research Laboratory (ARL), which works in partnership with other defense laboratories, industry and academia. The ARL is exploring many quantum technologies that would have direct applications to the war-fighter, but its scientists also expect to uncover hitherto unknown uses that emerge with laboratory discoveries and experimentation.

“Quantum has a lot to offer,” says Fredrik Fatemi, chief scientist for the ARL quantum, information science and position, navigation and timing (PNT) essential research program. “These problems are extraordinarily complex, but the reward is worth it. The impact on the soldier on our ability to measure time and fields and to communicate and compute [constitutes] critical functions for the Army.”

Colin Reese, ARL Army research lead for the quantum, information science and PNT essential research program, explains the ARL perspective. “We see quantum as that long-term, revolutionary change that is going to impact the way the Army senses for both PNT and targets, where our folks are, imaging, computing, how we talk on the network … and really, multiple applications across the entire Army warfighter space,” he states.

Reese continues that many engineering problems remain at the basic foundational research/component levels. Solving these problems will be necessary to migrate quantum technologies out of the laboratory and into the ruggedized environment.

“We have to figure out not only where we can take this, but also what are the problems we have to overcome to move it outside the laboratory,” he says.

Fatemi expands on that perspective. “Quantum information science and quantum mechanics leverage unique properties of nature that can revolutionize sensors, clocks, communications and computing—all of which can have huge impact on the Army mission,” he points out. Having better clocks and sensors for acceleration and rotation can aid a soldier in a GPS-denied environment, he suggests. Field sensors such as magnetometers can help identify metallic objects and tunnels underground. And quantum computing can solve classically intractable problems, particularly for cryptography.

“For quantum information science, understanding the nonintuitive properties and how they can be used for the warfighter, intrinsically relies on precision measurement,” Fatemi says. “This entails knowing your environment very well, knowing how to measure magnetic fields very well and control them, knowing how to measure accelerations and other perturbations to the system.” Describing quantum as a pervasive field, Fatemi offers that almost any normal sensor can be enhanced using quantum principles.

Part of the ARL’s responsibility for quantum research includes advising the Army on the responsible investments the service should make in quantum technologies. “We are looking to find the art of the possible and then working with other Army and industry partners to hone that down to what is practical,” Fatemi says.

While the ARL is engaged with industry partners, the commercial sector and academia do not necessarily have the same goals in mind as the Army lab. Their applications are not geared toward Army operations, let alone ruggedized for the battlefield, Fatemi points out.

The first application likely to benefit from ARL quantum work is atomic clocks, Fatemi offers. These devices form the backbone of most PNT systems, and they are at the heart of alternatives to GPS. Nearer-term research is focusing on the development of more portable atomic clocks and timekeeping devices, as well as inertial sensors such as accelerometers, rotation sensors and gyroscopes. These new systems would not need to continuously communicate with the GPS constellation for position and time, he notes.

Another capability that might come on the heels of the development is tunnel or bunker detection. Quantum technology would be used to measure mass anomalies, indicated by variations in gravitational fields, where enemy forces or nuclear materials might be hidden from sight or surface attacks.

Then there is quantum entanglement, in which unique correlations are established between two remote particles. Security in communications and computing will benefit from this research, which would be applied directly to Army needs.

Reese emphasizes that, in addition to better security, communications would be able to accommodate more users with more bandwidth across the network. Sensors would have enhanced radio frequency and electronic warfare capabilities, both for detecting threats and for resisting them. And precision-guided munitions would be more precise and require less human interaction.

“One thing our research in quantum science does is it allows us to think about classical problems in nontraditional ways,” Fatemi says. This includes, for example, developing novel sensors in ways the scientists weren’t even anticipating. Near-term advances using quantum technologies “are pretty well mapped out” in terms of their needs, but other areas are opening up to quantum capabilities as research advances.

One area, electric field sensing, traditionally employs antennas to measure signals. But research has unveiled quantum systems that can measure electric fields in a different way with totally atypical properties from conventional antennas. Being able to sense electromagnetic information using quantum science could lead to unique capabilities that have not even been considered, he suggests.

Fatemi explains that researchers were looking at exotic states of various different atoms as quantum information processing platforms. That’s a very different application from sensing, he points out, but investments made in quantum information processing led down this alternate path for using atoms in electrical field sensing. This is one case in which quantum research aimed at exploiting older principles led to a new application.

Many of today’s sensors rely on manipulating individual atoms, he points out. The same holds true of the best atomic clocks, which rely on gases of individual atoms. In searching for materials that can mimic atom-like behavior, scientists have been exploring an offshoot of quantum into material science, Fatemi says. Similar approaches have resulted in laser developments that have origins in quantum information science advancements.

“A lot of the gains that quantum realizes are in some of the tangents,” Reese offers. “Because of how pervasive quantum mechanics is, it sits at the intersection of material, computer, information and engineering sciences. You can have these branches into, say, material science where you are designing materials that you wouldn’t necessarily have had if you weren’t going down the quantum route,” he explains.

“Quantum is one of those research areas throughout the world that is kind of that next ‘space race’ between countries,” Reese notes. “A lot of countries are dumping a lot of money into research hoping to really have that impact on their sensing, communications and computing.

“While we’re doing our research as well, we are learning where are the smart places to put our research money and to partner with any friendly country, company or academia that are chasing the same applications,” he continues. “Some of this is understanding where the world is pushing the bar, and where is the world chasing the wrong window.”

Fatemi admits that “a whole suite” of technological challenges remains to be overcome to move quantum science into technology. Advanced lasers, vacuum systems, and detection systems that are low-cost and battlefield capable must hurdle several obstacles before they are realized. Designs must be ruggedized and fully effective to work on the battlefield, which requires far more stringent standards than found in the commercial sector. And in addition to technology challenges, the effort must address workforce development.

ARL scientists are enthusiastic at the prospects of known capabilities being enhanced or even revolutionized by quantum applications, Fatemi notes. “But what gets a lot of us excited are the question marks,” he reports. “What novel things are we going to find, and what novel ways are we going to deal with and develop to protect our soldiers and give them capabilities that they wouldn’t have had if we had just followed a linear approach to research?”