Title image: U.S. Rep. Joe Neguse, right, tours the lab of physicist Jun Ye at JILA in December 2021. Photo by Glenn Asakawa/CU Boulder.

CU Boulder has long been a leader in quantum research. Four out of the university’s five Nobel Prizes have come from researchers studying the quantum realm at JILA, a joint research institute with the National Institute for Standards and Technology (NIST). The university also has launched a number of quantum research initiatives in recent years, including CUbit Quantum Initiative, Quantum Systems through Entangled Science and Engineering (Q-SEnSE) and the Quantum Engineering Initiative.

To recognize World Quantum Day on April 14, organized by scientists from around the world to raise awareness of the field, CU Boulder Today talked with three quantum research graduate students: Jacob Beckey, who works at JILA to design the quantum computers of the future; Gregory Krueper, who explores the physics of optical fiber in the Department of Electrical, Computer and Energy Engineering; and Joanna Lis, who traps and manipulates atoms using lasers at JILA.

They spoke about what the future holds for quantum physics and how quantum discoveries have already fueled the modern, digital age. 

First off, what is quantum physics?

Beckey: Quantum physics is a model of the universe that describes, incredibly accurately, the behavior of tiny particles such as electrons and protons. Understanding the quantum realm has allowed scientists to make descriptions of chemical processes, the functioning of important devices in many electronics called semi- and superconductors, light-matter interaction and much, much more. 

Lis: As objects become smaller and smaller, and you go to colder and colder temperatures, the physics starts to deviate from our normal day-to-day experience. For example, an atom absorbs and emits well-defined amounts, or “quanta,” of light. 

Another quantum feature is entanglement, a correlation between atoms or other systems in which measuring one atom affects the outcome of measuring the others. Finally, in quantum physics the act of measurement is also very different. In classical physics, I can measure the position and speed of an object at the same time. In quantum physics, once I know the position very precisely, I have no way of knowing how fast the objects moves. 

How might quantum discoveries change the lives of everyday people?

Beckey: Quantum theory underlies some of the most important innovations of the past century, including radiation therapy, MRIs and lasers. If it were not for a deep understanding of quantum mechanics, the transistor would not have been invented. So, in a sense, we have quantum theory to thank for the modern digital age. 

Lis: Quantum technology has already started to replace classical technology in the realm of secure communication. Quantum cryptography relies on the laws of quantum physics to securely encode or decode a message. An everyday person might one day deploy quantum communication while making a credit card transaction.

Why did you decide to go into this field?

Lis: During my undergraduate studies, I took two classes on quantum theory and quantum information given by two incredible lecturers, and I found myself wanting to learn more. I really enjoyed working in the lab, troubleshooting problems, so I decided that experimental atomic physics combines my two interests the best. Also, throughout my undergraduate education, I had amazing female professors as role models who really encouraged and inspired me to stay in academia. 

Krueper: As an undergraduate, I had several projects focused on designing sensors to measure some quantity—the concentration of chemicals in a sample, for instance. Soon after moving to Boulder, I learned we can use quantum physics to enhance the measurements in these sensors, especially in optics. In that moment, quantum physics became for me, not something to just learn and work through, but to leverage and engineer to our advantage.

Can you tell me a little about your research?

Krueper: My research focuses on measuring certain properties of optical fiber—glass wires that are commonly used in telecommunications and remote sensing. I study how quantum states of light can enhance the precision of measurements in an optical fiber sensor. These sensors may, for instance, measure vibrations and temperature deep underground. 

Beckey: My research thus far has been at the intersection of quantum sensing and quantum computing. With collaborators at Los Alamos National Lab, I have developed an algorithm designed to be run on a quantum computer that can maximize the sensitivity of quantum sensing. This is a task that is very challenging for a classical computer, so it represents an interesting application of quantum computers. 

Lis: My group traps individual atoms in tightly focused laser beams, called tweezers, and cools the atoms to very cold temperatures—100 million times colder than room temperature. We image those individual atoms and precisely manipulate them with laser light fields. 

What do you see as the future for quantum research?

Beckey: I am hopeful within the coming decades we will see quantum sensors and quantum computers leading to discoveries with real-world impacts that simply would not have been possible with classical technologies.

Krueper: People talk about the imminent “second quantum revolution” as a time in which quantum technology becomes practical. An early example of this is the laser, which reformed everything from telecommunications to medical diagnostics. I expect quantum technology will seep more and more into the engineering disciplines, and some of these ideas will surely reach our daily lives.