Quantum mechanics offers improved communication possibilities

CSL Associate Professor Eric Chitambar is looking at how to enhance communication between devices by using quantum particles, rather than classical particles.

A common communication scenario involves two, three, or even hundreds of parties who attempt to simultaneously send a message to a single receiver. This can be formally

modeled by a multiple access channel, and the performance of such a channel depends on whether it is built using classical or quantum particles. Chitambar and his students have recently identified fundamental quantum advantages even in the extreme case of using just a single quantum particle.

While this result is more proof-of-principle than practical, it does motivate the development of quantum channels for use in more practical scenarios. One application for quantum-enhanced multiple access channels could be in public voting.

“Imagine we’re voting. We each have our own inputs and we’re sending in our ballots to a central voting station,” said Chitambar, an assistant professor in electrical and computer engineering. “There could be a million senders and one receiver. Using quantum particles for this task could enhance both the voting capacity and the security.”

At the heart of this idea is the mysterious fact that quantum particles can behave like waves. In the multiple access scenario, this wave can be sent simultaneously to all senders (voters), and then as the senders react, their responses can be packaged together and sent to a central receiving station. Besides allowing for a larger communication capacity in the multi-sender setting, quantum particles also provide cryptographic opportunities since any attempt to eavesdrop on the transmitted messages can be detected.

“Quantum cryptography offers security advantages that cannot be matched using classical schemes,” said Chitambar. “Voting is one particular application.  Another is authentication, in which two or more clients wish to verify they have matching data sets using the help of some central moderating system.  Protocols are known in which the clients need to send short amounts of quantum-encoded “fingerprints”, which can enable successful verification.  We have plans to implement schemes of this sort using the support of our recently-announced NSF quantum center award.”

The quantum center award referenced by Chitambar is the Institute for Hybrid Quantum Architectures and Networks (HQAN). A collaborative institute between the University of Illinois Urbana Champaign’s, Illinois Quantum Information Science and Technology Center (IQUIST), the University of Chicago, and the University of Wisconsin. Chitambar is one of the Illinois representatives in the $25 million center.

At the heart of this idea is the mysterious fact that quantum particles can behave like waves. In the multiple access scenario, this wave can be sent simultaneously to all senders (voters), and then as the senders react, their responses can be packaged together and sent to a central receiving station. Besides allowing for a larger communication capacity in the multi-sender setting, quantum particles also provide cryptographic opportunities since any attempt to eavesdrop on the transmitted messages can be detected.

“Quantum cryptography offers security advantages that cannot be matched using classical schemes,” said Chitambar. “Voting is one particular application.  Another is authentication, in which two or more clients wish to verify they have matching data sets using the help of some central moderating system.  Protocols are known in which the clients need to send short amounts of quantum-encoded “fingerprints”, which can enable successful verification.  We have plans to implement schemes of this sort using the support of our recently-announced NSF quantum center award.”

The quantum center award referenced by Chitambar is the Institute for Hybrid Quantum Architectures and Networks (HQAN). A collaborative institute between the University of Illinois Urbana Champaign’s, Illinois Quantum Information Science and Technology Center (IQUIST), the University of Chicago, and the University of Wisconsin. Chitambar is one of the Illinois representatives in the $25 million center.