Imagine a world where computers are millions of times as powerful as they are today. Instead of gene mapping a person’s DNA to treat disease, a program capable of mapping down to the protein level could provide highly-targeted cancer therapy. Or, perhaps a weather system model could predict the formation of a tornado, along with its specific path, with accuracy greatly surpassing anything possible today, providing far longer warning times and saving lives.
In a small but significant step toward that future, the Quantum Networking group at the Air Force Research Laboratory Information Directorate in Rome, New York, trapped Yb+ ions on April 14, 2017. This is the first ion-trapping demonstration at AFRL and also the first ion-trapping demonstration at an in-house Department of Defense research laboratory. The team is led by Dr. Kathy-Anne Soderberg, Primary Investigator, and Dr. Boyan Tabakov, co-Primary Investigator. These baseline demonstrations lay the groundwork for future quantum networking and distributed quantum computing applications. Establishing this trapped-ion capability allows RI to begin the critical first steps of connecting remote network nodes in a table-top experiment and mapping quantum information from individual trapped ions into photon-based qubits for the longer-term goal of transmitting quantum information between distance network nodes. The ion-photon mapping experiments are in conjunction with the AFRL/RI photon-based quantum computing laboratory led by Dr. Paul Alsing, Primary Investigator and Mr. Michael Fanto, co-Primary Investigator.
The idea of quantum computers is nothing new, according to story by Connie Zhou in Newsweek. Companies such as IBM, D-Wave and others have already developed small machines and are exploring commercial use. However, all of the machines use different technologies, each with their own limitations, and are still very much under development.
AFRL RI’s technology is focused on the potential of the trapped ytterbium (Yb+) ion.
Yb+ ions are positively charged atoms that can be trapped using electric fields. Trapped Yb+ ions can be used to store information in a quantum computer by acting as a quantum bit, or qubit, the basic unit of information in a quantum computer.
In a conventional computer, information is stored in bits, according to Alsing. The information stored in a bit can be either a 0 or a 1. In a qubit, the information can be a 0 and a 1, at the same time, in a physics rule called quantum superposition. In another quantum physics peculiarity, something called quantum entanglement allows the qubits to communicate in a fundamentally different way. Quantum entanglement is a special property shared between qubits that allows two qubits to interact with each other, regardless of how far apart they are. It’s an intricate relationship between the particles such that the state of one particle can impact the state of the other particle, even if they are not in direct contact with each other.
Trapped ion qubits are one of the leading contenders to realize a quantum computer due to the long-lived ground state qubit levels, quality of entanglement demonstrated, and targeted operations possible within the system, says Soderberg. All of these capabilities can be leveraged for quantum networking applications. Trapped ions are the longest-lived qubits to date, demonstrating coherent memory storage times up to 15 min; this makes them ideally suited for memory nodes in a quantum network.
The Quantum Networking team members are Dr. Kathy-Anne Soderberg (PI), Dr. Boyan Tabakov (co-PI), Dr. Daniela Bogorin (National Research Council Fellow), Ms. Laura Wessing, Lt Kaitlin Poole, Lt Lester Disney, Mr. Paul Cook, and Mr. Justin Phillips (co-op student from Northeastern University). This work was funded in part under the Office of the Secretary of Defense (OSD) Applied Research for the Advancement of Science and Technology Priorities (ARAP) Quantum Science Engineering Program (QSEP).