Stony Brook University, New York
Eden Figueroa has long been fascinated by quantum mechanics.
It’s a strange, Star Trek-like world in which objects can exist in two or more states simultaneously, interact with each other instantly over long distances, and also come in and out of existence. Scientists like Figueroa – the head of quantum information technology research in the Department of Physics and Astronomy at Stony Brook University – are working to exploit this behavior in hopes of turning it into a new one. Internet improved.
âI think the Internet is one of the greatest things humanity has ever done. But it’s not perfect, âFigueroa said. âWhat we want is a fast and secure Internet. These are the two questions to which there are currently no answers.
Despite the high level of physics involved, the premise of the real world challenge is no deeper than that.
âWhen you have Zoom meetings, you don’t want to lose other attendees, and if you use your credit cards for internet transactions, you don’t want people to get your information,â Figueroa said. “These are examples that everyone can relate to.”
Technology is generally developed incrementally and organically; it starts small and grows. Unfortunately, this has not happened with the Internet.
âIn a short time, we went from a small network of researchers to a global network where everyone is connected,â said Figueroa. âIt was amazing and it changed the world. But nobody paid attention along the way to things like internet security or transferring amounts of data that were previously unimaginable. “
While a standard computer handles digital bits of 0 and 1, quantum computers use quantum bits that can take any value between 0 and 1. And if you intermingle the bits, you can solve problems that conventional computers can not. Figueroa says the main challenge in building these quantum lattices is to demonstrate that they work with single photons, and to show that you can transfer entanglement into a lattice by using it whenever you need to.
âThis is a very famous quantum teleportation experiment,â he said. âIf you have an entanglement, you have quantum teleportation, so you can move information from one place to another. If you can manage to have a lot of photons that are all entangled, then you can – in principle, using quantum teleportation – transfer a lot of data from one place to another. Once we get there, the challenge is to transfer these entangled photons over longer distances. “
Figueroa arrived at Stony Brook in 2013, the first professor hired to do quantum information science specifically, tasked with building both a lab and a program. Eight years later, Figueroa and his team of 12 graduate students and two undergraduates aim to develop and implement the first network of quantum-agnostic repeaters.
âAll of the technology that we are developing in this lab is intended to create an early version of this quantum repeater,â he said.
The test bed for his ideas is a quantum network connecting sites at Stony Brook and the Brookhaven National Laboratory (BNL), about 27 km away. Figueroa used the existing fiber optic infrastructure and deployed entanglement sources and quantum memories in several buildings on the BNL campus, with fibers used to quantically connect the physics and instrumentation buildings with the Data Center and scientific calculations. A similar local quantum network has been developed at the Stony Brook campus.
With the quantum communication channels in place, Figueroa uses the sources of photon entanglement to simultaneously store and retrieve quantum correlations in four quantum memories on both campuses. In 2020, the team successfully transmitted single-photon-level polarization quantum bits (qubits) in a configuration spanning a total of approximately 87 miles. This marked longest successful quantum communication binding experience in the USA.
âOver the past two or three years, the problem has become more serious,â Figueroa said. âNow we have ‘toys’; how to network them? This is what makes us unique. With these test benches, we are really test devices in these network configurations, and really move quantum information over longer distances. It’s very original. In the United States there are only a few test beds, but I think the one we have is by far the most advanced right now. “
Figueroa is not the only one working for this great vision. His small but extremely dedicated team shares his passion and does whatever it takes to advance the cause. To illustrate this point, Figueroa shows a network of working models in his laboratory, with optical tables built with components that had to be manufactured, assembled and placed with precision. âOnce you’ve built them all, you need to align them to serve a purpose,â he said. ” It’s a lot of work “
Doctoral candidate Guadong Cui ’22 is one such team member and describes the quantum challenge as one of âdepth and prosperityâ.
âIf you ask a serious thinker the question, the entanglement is just impossible – it’s like working with a ghost, except that a ghost would have been a lot easier to understand,â Cui said. âYet it is possible, because we generate, process and even build a quantum gate for it. The fact that I am working on a project that touches both my deepest curiosity as a person and serves the need to revolutionize information technology for human beings makes this work incredibly interesting.
âWhat I like about quantum communication is that fundamental questions about light-matter interaction are studied in parallel with engineering strategies to converge towards the goal of building future technology,â added doctoral candidate Sonali Gera, ’21.
Another member of the team, Leonardo Castillo Veneros, physics student, ’22, focuses on room-temperature quantum memories and finding their optimal operating regimes.
âBefore I enrolled at Stony Brook, about four years ago, I visited the Quantum Information Laboratory on a campus tour and was blown away looking at the setups on the optical tables,â said Castillo Veneros.
After this tour, Castillo Veneros enrolled at Stony Brook as a major in physics in the fall of 2017 and began working at the Quantum Lab in the spring of 2018. He has been a part of it ever since.
Rishikesh Gokhale ’25 is working on the development of a free space quantum communication channel between the Brookhaven National Laboratory and Stony Brook.
âI love that I’m working on something that would replace a lot of the existing communication network and make communication safer and faster,â said Gokhale, ’25, who is pursuing a doctorate in physics. âI was interested in the rapidly expanding field of quantum information and at the same time, I wanted to be an experimenter. Professor Figueroa’s lab gives me the opportunity to do this.
All team members thank Figueroa for being able to offer advice while giving team members the freedom to explore their individual interests within the project. Rishikesh adds that Figueroa offers the âfreedom to think, implement and improvise. We ask for his help whenever it is needed.
âHis passion and dedication on the pitch is incredibly inspiring and motivating,â said Castillo Veneros. âWhen I first learned about the kind of work he was doing, I wanted to be a part of it. I am grateful for the opportunity to contribute to this extraordinary effort to build a quantum network on Long Island. “
As the project progresses, Figueroa hesitates to set a timeline for it, noting that no progress is ever a certainty.
âIf we had unlimited funds, which we never do, I would say the horizon is around five years,â he said. âWith our current funding, this will last for more than 10 years. We still need to test this network setup and every part of it to get it right. Once there, we can increase that. But it is revolutionary research that we are currently carrying out and we are training the leaders of tomorrow in this field. It’s a unique story for Stony Brook. And I like it.”
– Robert emproto
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