News & Research Highlights

Some of the biggest questions about our universe may be solved by scientists using its tiniest particles. Since the 1960s, physicists have been looking at particle interactions to understand an observed imbalance of matter and antimatter in the universe. Much of the work has focused on interactions that violate charge and parity (CP) symmetry. This symmetry refers to a lack of change in our universe if all particles’ charges and orientations were inverted. “This charge and parity symmetry is the symmetry that high-energy physicists say needs to be violated to result in this imbalance between matter and antimatter,” explained JILA research associate Luke Caldwell. To try to find evidence of this violation of CP symmetry, JILA and NIST Fellows Jun Ye and Eric Cornell, and their teams, including Caldwell, collaborated to measure the electron electric dipole moment (eEDM), which is often used as a proxy measure for the CP symmetry violation. The eEDM is an asymmetric distortion of the electron’s charge distribution along the axis of its spin. To try to measure this distortion, the researchers used a complex setup of lasers and a novel ion trap. Their results, published in Science as the cover story and Physical Review A, leveraged a longer experiment time to improve the precision measurement by a factor of 2.4, setting new records. 

JILA graduate student Alexander Aeppli is one of a team of researchers working on the world’s most precise clocks. In the laboratory of JILA and NIST Fellow Jun Ye, Aeppli focuses on improving the strontium atomic clock using powerful ultrastable lasers. “The laser drives an electronic transition in strontium,” Aeppli explained. “And we want to make sure the transition within the strontium is exact.” Before the transition occurs, the strontium atoms are trapped within an optical lattice inside the clock. Once trapped, the strontium atoms can transition when exposed to a particular color (or frequency) of light, and the researchers, like Aeppli, measure this transition frequency as a form of timekeeping. The frequency can then be used as the precise standard of time worldwide.  

JILA's Postdoc Group, an internal organization supporting postdoctoral researchers within JILA, held a career panel titled: "Insights for Applying for Faculty Positions as a Postdoctoral Researcher." The panel featured three JILA Fellows: Margaret Murnane, Shuo Sun, and Graeme Smith, and J. Curtis Beimborn II, the Director of the W.M. Keck Laboratory at JILA, who recently accepted a faculty position on the East Coast. 

The best clock in the world has no hands, no pendulum, no face or digital display. It is made of ultra-cold atoms trapped by light.  This atomic clock is so precise that, had it begun ticking when Earth formed billions of years ago, it would not yet have gained or lost a second. Nonetheless, this incredible clock, and all atomic clocks, operate with collections of independent atoms, and as a result, their precision is limited by the fundamental laws of quantum mechanics.  One way to get around this fundamental quantum imprecision is to entangle the atoms, or make them talk, in such a way that one cannot describe the individual atoms’ quantum states independently of one another. In this case it is possible to create the situation where the quantum noise of one atom in the clock can be partially canceled by the quantum noise of another atom such that the total noise is quieter than one would expect for independent atoms. One type of entangled state is called a “squeezed state”, which can be visualized as if one had shaped the quantum noise in a way that is narrower in one direction at the expense of making the fuzziness in the adjacent direction worse.  Squeezed states have been realized in several labs around the world at groundbreaking precision levels recorded by several physics institutes, including  at JILA in Boulder, Colorado.  However, squeezing is experimentally challenging to create and there is a need for a variety of “flavors” of squeezing for different types of quantum sensing tasks.

A new approach recently described in Physical Review Letters explores a new way to generate squeezing that is exponentially faster than previous experiments and generates a new flavor of entanglement:  two-mode squeezing—a type of entanglement that is thought to be used for improving the best atomic clocks and for sensing how gravity changes the flow of time. This promising new approach was developed by a collaboration of JILA and NIST Fellows Ana Maria Rey and James K. Thompson, and their team members, along with Bhuvanesh Sundar, a former postdoctoral researcher at JILA now at Rigetti Computing, and former JILA research associate Dr. Robert Lewis-Swan, now an Assistant Professor at the University of Oklahoma.

Although one might think it would be simple, the genetics of bacteria can be rather complicated. A bacterium’s genes use a set of regulatory proteins and other molecules to monitor and change genetic expressions within the organism. One such mechanism is the riboswitch, a small piece of RNA that can turn a gene “on” or “off.” In order to “flip” this genetic switch, a riboswitch must bind to a specific ion or molecule, called a ligand, at a special riboswitch site called the aptamer. The ligand either activates the riboswitch (allowing it to regulate gene expression) or inactivates it until the ligand unbinds and leaves the aptamer. Understanding the relationship between ligands and aptamers can have big implications for many fields, including healthcare.  “Understanding riboswitches and gene expression can help us develop better antimicrobial drugs,” explained JILA graduate student Andrea Marton Menendez. “The more we know about how to attack bacteria, the better, and if we can just target one small interaction that prevents or abets a gene from being translated or transcribed, we may have an easier way to treat bacterial infections.”  
To better understand the dynamics of aptamer and ligand binding, Marton Menendez, along with JILA and NIST Fellow David Nesbitt, looked at the lysine (an amino acid) riboswitch in Bacillus subtilis, a common type of bacterium present in environments ranging from cow stomachs to deep sea hydrothermal vents. With this model organism, the researchers studied how different secondary ligands, like, potassium, cesium, and sodium, affect riboswitch activation, or its physical folding. The results have been published in the Journal of Physical Chemistry B.

JILA and NIST Fellow, along with University of Colorado Professor Konrad Lehnert will be leading a project through the Department of Defense (DoD) competitive Multidisciplinary University Research Initiative (MURI) Program. CU Boulder was matched only by the Massachusetts Institute of Technology in receiving three MURI awards. 

JILA Fellow and University of Colorado physics professor Heather Lewandowski helped lead a group of more than 1,000 undergraduate students in a study looking at the temperatures of the Sun's corona. The corona, the outer layer, gets incredibly hot, and the study hoped to figure out why. Their research was featured in Popular Science Magazine, revealing the creativity and ingenuity of undergraduate students in scientific research. 

JILA and NIST Fellows David Nesbitt's and Jun Ye's recent results in their breathalyzer study have been highlighted in a new article in Scientific American. Using frequency combs, a particular type of laser array, scientists could detect specific molecules in the breath, including diseases like COVID-19. This research suggests huge implications for the future of disease diagnosis and prevention. 

For a new study, a team of physicists recruited roughly 1,000 undergraduate students at CU Boulder to help answer one of the most enduring questions about the sun: How does the star’s outermost atmosphere, or “corona,” get so hot?

The research represents a nearly-unprecedented feat of data analysis: From 2020 to 2022, the small army of mostly first- and second-year students examined the physics of more than 600 real solar flares—gigantic eruptions of energy from the sun’s roiling corona. 

The researchers, partially lead by JILA fellow Heather Lewandowski, and including 995 undergraduate and graduate students, published their finding May 9 in The Astrophysical Journal. The results suggest that solar flares may not be responsible for superheating the sun’s corona, as a popular theory in astrophysics suggests. 
 

Election to the National Academy of Sciences (NAS) is one of the highest honors that can be bestowed upon a scientist in the United States, and it is a mark of recognition for exceptional scientific achievement. This achievement has now been bestowed on JILA and NIST Fellow, along with the University of Colorado Boulder physics professor Ana Maria Rey, as she was inducted into the NAS in 2023. 

While many JILA alumni go onto have more traditional careers such as in quantum industry, other career paths that might not be as well-known offer some unique benefits. One of these career paths is in medical physics research.  Medical physics is an important and rapidly growing field that is dedicated to the application of physics principles and techniques to medicine and healthcare. Medical physicists are experts in the use of radiation and other technologies to diagnose and treat disease, and they play a vital role in ensuring the safety and effectiveness of medical procedures. They also research and develop the next generation of tools for diagnostic imaging and radiation therapy. For JILA alumni Liz Shanblatt, a Staff Scientist and Collaboration Manager at Siemens Healthineers, medical physics became an interest only as she was nearing graduation and starting to look for jobs.

Heidi Shyu, undersecretary of defense for research and engineering at the U.S. Department of Defense, visited JILA and the University of Colorado Boulder on Monday to glimpse the future of cutting-edge research.

From the university’s proximity to national laboratories and quantum-intensive companies to the high volume of pioneering alumni, CU Boulder has long been a leader in the quantum space. This legacy has led to a push in innovation and technology, including as it pertains to national security—a goal also shared by Shyu and the Department of Defense.

Dipolar gases have become an increasingly important topic in the field of quantum physics in recent years. These gases consist of atoms or molecules that possess a non-zero electric dipole moment, which gives rise to long-range dipole-dipole interactions between particles. These interactions can lead to a variety of interesting and exotic quantum phenomena that are not observed in conventional gases. 

JILA and NIST Fellows Jun Ye and David Nesbitt, along with their respective teams, have recently been highlighted in the latest issue of the SPIE Photonics West Show Daily, a publication from SPIE. This highlight focuses on the recent advancements in the frequency comb breathalyzer apparatus that the researchers have built and tested, which looks at diagnosing COVID-19 and other diseases.

JILA researchers have upgraded a breathalyzer based on Nobel Prize-winning frequency-comb technology and combined it with machine learning to detect SARS-CoV-2 infection in 170 volunteer subjects with excellent accuracy. Their achievement represents the first real-world test of the technology’s capability to diagnose disease in exhaled human breath.

Every year the National Institute of Standards and Technology (NIST) and the Department of Commerce (DOC) grant honor awards in the form of Gold, Silver, and Bronze Medals. According to the DOC website: “the Gold and Silver Medals are the highest and second highest honor granted by the Secretary for distinguished and exceptional performance.” Two of JILA’s Fellows, Jun Ye, and Judah Levine, have been awarded these medals.

Some of the most important research and discoveries in science have been made by women. To celebrate these inspiring individuals and to support the next generation of female scientists, the United Nations dedicated February 11 as "International Women and Girls in Science" day. To honor this tradition, JILA hosted a panel discussion/open-forum with both JILA Fellows and JILA staff as speakers.

When a superconducting material is cooled down below a critical temperature, something seemingly magical happens: its electrical resistivity drops abruptly to zero! Initially, before 1911, this was thought to be impossible, given that electrons, which are the particles that carry electric current, typically scatter from impurities and imperfections of a crystal lattice used in conducting materials.  Moreover, because electrons are negatively charged particles, they typically repel each other. Yet, behind the “magic” of superconductors is the fact that two electrons, in a periodic crystalline array of atoms (a web of lasers), can attract positive charges in the lattice, whose subsequent deformation mediates an attractive interaction between the electrons. This attraction favors electrons with opposite momenta to bind together, forming ‘Cooper pairs’. These pairs can coalesce into a coherent macroscopic quantum state of matter, in which they remain paired while flowing through the crystal without any resistance. Beyond their immense practical applications, superconductors also offer a promising testbed to study the fundamental physics of matter held far away from equilibrium.

In a conventional superconductor (‘s-wave’ superconductor), the two electrons in a Cooper pair must have opposite spins. But there are unconventional superconductors with p-wave symmetry, in which electrons of the same spin pair up.  This pairing is penalized by an energy barrier and in order to overcome the barrier and pair up, electrons need to carry a non-zero angular momentum, which means that they need to spin around each other. The net angular momentum of the Cooper pairs can give rise to rich quantum behaviors and phases of matter that are intensively sought in real materials and cold atoms, but have, so far, remained elusive.  In particular, the dynamics of p-wave superconductors taken away from equilibrium is predicted to exhibit a variety of temporal behaviors, some of which possess interesting quantum dynamics. Observing these ‘dynamical phases’ in the lab would provide a window into the nature of non-equilibrium phases of matter and some of their properties, and potentially new p-wave superconductors. In cold gases, one of the biggest challenges that has prevented researchers from observing p-wave physics is three-body losses in energy that emerge when weak p-wave interactions are enhanced via external electromagnetic fields. However, to date, liquid 3He remains the only well-established laboratory example of a p-wave superconductor.

To overcome these challenges, JILA and NIST Fellow Ana Maria Rey collaborated with NIST (National Institute of Standards and Technology) Ion Storage Group leader John Bollinger, and researchers at the University of Innsbruck, Rutgers University and the University of Colorado Boulder, to design a trapped-ion simulator for 2D p-wave superconductors. Their work paves a way for clean observations of the predicted non-equilibrium dynamics in future experiments using the trapped-ion simulator, or Penning trap. The researchers published their findings in PRX Quantum.

Quantum gases of interacting molecules can exhibit unique dynamics. JILA and NIST Physicist Jun Ye has spent years of research to reveal, probe, and control these dynamics with potassium-rubidium molecules. In a new article published in Nature, Ye and his team of researchers describe having combined two threads of previous research—spin and motional dynamics—to reveal rich many-body and collisional physics that are controllable in the laboratory. 

When it comes to creating ever more intriguing quantum systems, a constant need is finding new ways to observe them in a wide range of physical scenarios.  JILA Fellow Cindy Regal and JILA and NIST Fellow Ana Maria Rey have teamed up with Oriol Romero-Isart, a professor at the University of Innsbruck and IQOQI (Institute for Quantum Optics and Quantum Information) to show that a trapped particle in the form of an atom readily reveals its full quantum state with quite simple ingredients, opening up opportunities for studies of the quantum state of ever larger particles.