This NASA-funded experiment will evaluate two technologies that could enable quantum computers to communicate with one another regardless of where they are situated.
This year, a little experiment will launch on the International Space Station. It could be the beginning of a global quantum network. The Space Entanglement and Annealing QUantum Experiment (or SEA QUE) demonstrates two communication technologies in space. It’s a milk carton-sized technology demonstration.
Quantum computers promise to operate millions of times faster than conventional computers. Distributed quantum sensors could lead to new understandings of Earth and our place within the universe by measuring tiny changes in gravity. A dedicated communications network is required to communicate with quantum computers and quantum sensors. Space “nodes”, which can transmit and receive quantum data via free-space optical communications, will be a key component of the network.
EAQUE aims to demonstrate the viability and security of technologies that enable orbiting nodes securely to connect quantum receivers and transmitters over large distances. These nodes must produce and detect pairs of entangled photons. These photons could eventually be transmitted to quantum computers on the ground, allowing for the exchange and processing of quantum data from any location.
Once attached to the station’s exterior, SEA QUE also will test a technique that helps space-based nodes “self-heal” from radiation damage. This is a constant challenge for delicate instruments in space.
These two technologies demonstrate the foundation for future global quantum networks, which can connect quantum computers located hundreds of thousands of miles apart,” Makan Mohageg (SEA QUE co-investigator at NASA’s Jet Propulsion Laboratory) in Southern California.
The project is global, just like the network; it’s meant to facilitate. The SEA QUE collaboration comprises scientists and students at the University of Illinois Urbana-Champaign, which is leading the project; the National University of Singapore in Ontario, Canada; Montana-based industrial partner AdvR, Inc., Texas-based commercial satellite systems provider Nanoracks; JPL.
The Power of Entanglement
Because of their intimate connection, measuring two entangled photons at once can affect each other even if great distances separate them. This is a fundamental property of quantum mechanical systems. SEAQUE’s entangled photon source divides high-energy photons into pairs of entangled, “daughter” photons. The instrument’s internal detectors measure the quantum properties of these daughter photons and count them.
SEAQUE uses a waveguide to create entangled photos. This is a new space-based quantum experiment. Waveguides are microscopic structures that act as an expressway for photons and direct their transmission with minimal loss of quantum state.
SEAQUE will show a new, never-before-flowed entanglement source based upon integrated optics,” stated Paul Kwiat at the University of Illinois Urbana-Champaign. “Such a source is intrinsically smaller, stronger, and more efficient in producing photon pairs than bulk optic entanglement suppliers used in space experiments in the past.”
SEAQUE optics can be used in cases where bulk optics need to be adjusted by an operator on the ground.
Mohegan stated, “If you are building a global quantum network connecting hundreds of quantum ground station on different continents you can’t afford to pay for a person in the loop keeping the sources at the nodes aligned optically.” “A monolithic, waveguide-based source such as the one SEAQUE will fly will make a significant advance towards scalable, global quantum information networks.”
Laser Therapy
If SEA QUE can prove that it can repair radiation damage to the technology demonstration, it could give it an additional boost in reliability.
To receive single-photon quantum signals from Earth, quantum communications nodes will need highly sensitive detectors. Over time, defects will develop as high-energy particles or radiation from space hit nodes’ detectors. These defects may manifest as a “dark count” in the detector’s output, which can create noise that eventually overwhelms any quantum signal from the ground. Space radiation can eventually degrade these detectors, causing them to need to be replaced frequently. This will hinder the viability and growth of a global quantum communications network.
Although detecting signals from Earth is not within the scope of this demonstration technology, SEA QUE will use the detector array to count photons produced by its entanglement sources. SEAQUE will also use a bright laser periodically to repair radiation-induced damage to the detector array. This is another first.