In the bustling realm of scientific exploration, there are individuals whose dedication allows them to stand out as a leader within their research group. Such is the case for JILA graduate student Luca Giuseppe Talamo, a researcher within JILA Fellow Cindy Regal’s group.
For Talamo, the journey to JILA was far from linear. “Originally, when I went to undergrad, I thought I wanted to attend med school and be a doctor,” Talamo elaborated. “I had friends in my math and physics classes who saw that I was getting more enjoyment out of those courses than my life science courses.” From this observation, Talamo’s friends encouraged him to participate in more upper-level physics classes during his undergraduate career at the University of Toronto.
Once he switched from life sciences to physics, Talamo was welcomed into a close community. According to Talamo: “We spent countless hours in the physics lounge, working on problem sets with each other and trying to go over lectures. There was a lot of discussion and learning outside of the classroom. That community encouraged me to stay in physics and math.”
Along with his newfound interest in physics, Talamo participated in an electronics course and discovered that he enjoyed building his own instruments, starting with a blueprint and finishing with a working model. “I think that exposed me to the joys of designing something, troubleshooting it, and seeing the initial design come to fruition (or more often than not realizing why it won’t work),” he added. Working in an atomic physics laboratory as an undergraduate prepared Talamo to transition to JILA, as he received hands-on training with laser arrays and vacuum chambers.
For Talamo, it took his undergraduate professor Amar Vutha to encourage his class to “be bold” for Talamo to ask for a position in Vutha’s laboratory. Talamo elaborated: “While there, I performed optical spectroscopy on atoms in a cryogenically cooled crystal, which introduced me to the world of AMO physics. Amar also informed me of the strong AMO research culture at JILA and encouraged me to apply.”
Now, as a graduate student at JILA, Talamo finds himself at the forefront of cutting-edge science. “I am working on a joint project between Konrad Lehnert [another JILA Fellow] and Cindy,” he elaborated. “This project aims to utilize mechanical objects to link up two disparate parts of the electromagnetic spectrum – microwaves and optics. While both propagate through free-space in the form of photons the later have energies that are roughly forty thousand times higher than the former By sticking these mechanical objects in specialized fridges known as dilution refrigerators and using laser-cooling techniques, we can cool these mechanical objects to almost-absolute-zero temperatures. This lets us take information from the microwave domain and transfer it to the optical domain. We’re trying to do this in a way that’s as efficient and low-noise as possible to transfer sensitive quantum information between these two domains in reasonable amounts of time. Because of the energy disparity, this is actually a very difficult task.”
Transferring information from microwave frequencies to optical frequencies would open various applications, from quantum computing to satellite communications. “There are a lot of academic and industry groups right now that are working on trying to build quantum computers,” Talamo said. “Several of these groups are trying to use superconducting microwave circuits to store and process the information, and these circuits need to be very, very cold to preserve quantum signatures. The standard way to do this is to put them in specialized refrigerators known as dilution refrigerators, which can cool things down to about 10mK. To get a sense of the temperature scales, I am to that coldest part of the fridge what the sun is to me.”
Unfortunately, linking up two superconducting processors in two separate refrigerators is a task that no one has been able to accomplish yet. Microwave cables can’t transmit quantum information a room temperatures because of how little energy microwave photons have – the ambient thermal radiation dwarfs very sensitive quantum signals.. The platform that Talamo is currently working on tries to circumvent the need to keep connecting cables cold. “It turns out that if you can take information from these processors and put it onto light, you can use fiber optic infrastructure to transfer information between processers,” Talamo added. “You would only need to keep the processor cold, but you wouldn't need to keep the fiber optic cable cold. Because it turns out that light is not as sensitive to the room temperature thermal environment as the processor.” Talamo, Regal, Lehnert, and the rest of the research team are hopeful that other groups can use this technology to advance the development of quantum computing and quantum information systems.
Despite starting his work with lasers during his undergraduate research, Talamo hasn’t stopped being amazed by what they can do. “Every day, I’m reminded how versatile lasers can be. We routinely use them as precision instruments to stabilize a path of a hundred meters to within the width of a human hair. We also use them to laser cool our mechanical objects to temperatures 1000 times colder than our ultra-cold refrigerators.”
With access to JILA’s many support shops, like the instrument shop or electronics shop, along with a broader community of researchers, Talamo feels that the institute is successfully preparing him for the next step in his career. “I have such a great community of experts,” he elaborated. “From Konrad and Cindy to the graduate students and postdocs I work with daily. There’s also the technical staff here - I don't know how most of the labs in JILA would get their work done without them. During my second year I was responsible for installing a new fridge in our already-tight lab space, and I was working with the machine shop staff every step of the way. In particular, Adam Ellzey was instrumental in making sure everything went smoothly during installation week. I’m forever grateful.
Beyond this, Talamo also highlights that JILA’s funding helps make it a key place for physics research. As he explained: “The PIs have amazing track records, so they get good funding. So, I think that takes more pressure off us grad students from having to constantly go out there and seek funding ourselves. It really is a great place to do research.”
Written by Kenna Hughes-Castleberry, JILA Science Communicator