News & Research Highlights

Isolated atoms in free space radiate energy at their own individual pace. However, atoms in an optical cavity interact with the photons bouncing back and forth from the cavity mirrors, and by doing so, they coordinate their photon emission and radiate collectively, all in sync. This enhanced light emission before all the atoms reach the ground state is known as superradiance. Interestingly, if an external laser is used to excite the atoms inside the cavity moderately, the absorption of light by the atoms and the collective emission can balance each other, letting the atoms relax to a steady state with finite excitations.

However, above a certain laser energy level, the nature of the steady state drastically changes since atoms inside the cavity cannot collectively emit light fast enough to balance the incoming light. As a result, the atoms keep emitting and absorbing photons without reaching a stable, steady state. While this change in steady-state behaviors was theoretically predicted decades ago, it hasn’t yet been observed experimentally.  

Recent research at the Laboratoire Charles Fabry and the Institut d’Optique in Paris studied a collection of atoms in free space forming an elongated, pencil-shaped cloud and reported the potential observation of this desired phase transition. Yet, the results of this study puzzled other experimentalists since atoms in free space don’t easily synchronize. 

To better understand these findings, JILA and NIST Fellow Ana Maria Rey and her theory team collaborated with an international team of experimentalists. The theorists found that atoms in free space can only partially synchronize their emission, suggesting that the free-space experiment did not observe the superradiant phase transition. These results are published in PRX Quantum. 

Physics lab courses are vital to science education, providing hands-on experience and technical skills that lectures can’t offer. Yet, it’s challenging for those in Physics Education Research (PER) to compare course to course, especially since these courses vary wildly worldwide. 

To better understand these differences, JILA Fellow and University of Colorado Boulder physics professor Heather Lewandowski and a group of international collaborators are working towards creating a global taxonomy, a classification system that could create a more equitable way to compare these courses. Their findings were recently published in Physical Review Physics Education Research.

JILA and NIST Fellow and CU Boulder Physics Professor Jun Ye has been named a 2024 Highly Cited Researcher by Clarivate. This distinction is awarded to scientists whose work ranks in the top 1% of citations globally. Ye, known for his groundbreaking contributions to precision measurement and atomic, molecular, and optical physics, joins an elite list of researchers shaping the forefront of scientific innovation.

JILA has officially launched its new Research Professional Development Program, an initiative designed to provide graduate students and postdoctoral researchers with comprehensive skills beyond their core scientific training. Focusing on leadership, mentorship, big-picture thinking, and equity in research environments, this program aims to equip participants with the tools they need to become successful scientific leaders.

Flari Tech Inc., a startup rooted in cutting-edge JILA research, has clinched one of the prestigious 2024 Lab Venture Challenge (LVC) grants from the University of Colorado Boulder, advancing its pioneering work to build a breathalyzer for diagnostics use targeting life-threatening diseases such as lung cancer.  

Developed at JILA by a team led by JILA and NIST Fellow and CU Boulder Physics professor Jun Ye and JILA graduate students Qizhong Liang and Apoorva Bisht, Flari Tech’s innovative diagnostic tool is powered by the Nobel Prize-winning optical frequency comb and aims to bring a novel, non-invasive, faster method for lung cancer detection for clinical use.
 

JILA Fellow and NIST (National Institute of Standards and Technology) Physicist and University of Colorado Boulder Physics professor Adam Kaufman and his team have ventured into the minuscule realms of atoms and electrons. Their research involves creating an advanced optical atomic clock using a lattice of strontium atoms, enhanced by quantum entanglement—a phenomenon that binds the fate of particles together. This ambitious project could revolutionize timekeeping, potentially surpassing the "standard quantum limit" of precision. 

In collaboration with JILA and NIST Fellow Jun Ye, the team highlighted their findings in Nature, demonstrating how their clock, operating under certain conditions, could exceed conventional accuracy benchmarks. Their work advances timekeeping and opens doors to new quantum technologies, such as precise environmental sensors.

In the world of quantum technology, measuring with extreme accuracy is key.  Despite impressive developments, state-of-the-art matter-wave interferometers and clocks still operate with collections of independent atoms, and the fundamental laws of quantum mechanics limit their precision.  

One way to get around this fundamental quantum fuzziness is to entangle the atoms or make them talk so that one cannot independently describe their quantum states. In this case, it is possible to create a situation where the quantum noise of one atom in a sensor 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. This type of entangled state is called a “squeezed state,” which can be visualized as if one had made a clock hand narrower to tell the time more precisely, a precision that comes at the expense of making the fuzziness along the clock hand worse.  However, preparing spin-squeezed states is no easy feat. 

Up to now, there have been two leading ways to generate squeezed states, using atoms that interact with light. One way, unitary evolution, is by transforming an initially uncorrelated (not entangled) state into a spin-squeezed state via dynamical evolution via a specific type of unitary interaction. One can imagine the initially uncorrelated state as a round piece of dough where your hand slowly squeezes the dough in one direction while making the other direction wider. 

The other way is to perform quantum nondemolition measurements (QND) that allow one to pre-measure the quantum noise and subtract it from the final measurement outcome.  The QND approach has currently realized the largest amounts of observed squeezing between the two methods, but it is not clear which protocol is actually optimal, given fundamental experimental constraints, or even if it would be better to use both protocols at the same time. 

This is why JILA and NIST Fellows and University of Colorado Boulder Physics professors Ana Maria Rey and James K. Thompson and their teams wanted to guide the community on which protocol is best to use under fundamental and realistic experimental conditions. Their results, published in Physical Review Research, revealed that when measurement efficiency is greater than 19%, the QND measurement protocol outperformed unitary dynamical evolution. This finding can have big implications for quantum metrology.

JILA postdoctoral researcher Simon Scheidegger has received the prestigious METAS 2024 Award from the Swiss Physical Society (SPS). Scheidegger, who is part of JILA and NIST Fellow Jun Ye's laboratory group, was awarded for his pioneering research on precise measurements of hydrogen energy levels during his PhD at ETH Zurich. 

The interactions between quantum spins underlie some of the universe’s most interesting phenomena, such as superconductors and magnets. However, physicists have difficulty engineering controllable systems in the lab that replicate these interactions.

Now, in a recently published Nature paper, JILA and NIST Fellow and University of Colorado Boulder Physics Professor Jun Ye and his team, along with collaborators in Mikhail Lukin’s group at Harvard University, used periodic microwave pulses in a process known as Floquet engineering, to tune interactions between ultracold potassium-rubidium molecules in a system appropriate for studying fundamental magnetic systems. Moreover, the researchers observed two-axis twisting dynamics within their system, which can generate entangled states for enhanced quantum sensing in the future. 

An international team of researchers, led by JILA and NIST Fellow and University of Colorado Boulder Physics Professor Jun Ye and his team, has made significant strides in developing a groundbreaking timekeeping device known as a nuclear clock. Their results have been published in the cover article of Nature. 

The second installment of the JILA JAGS (JILA Association of Graduate Students) Seminar series recently took place, featuring an exciting lineup of talks by graduate students pushing the boundaries of scientific research. 

The event highlighted the work of Bejan Ghomashi from the Becker Group, Trevor Kieft from the Lewandowski Group, and Emma Nelson from the Kapteyn/Murnane Group, who each presented their cutting-edge research to an engaged audience.

Many quantum devices, from quantum sensors to quantum computers, use ions or charged atoms trapped with electric and magnetic fields as a hardware platform to process information. 

However, current trapped-ion systems face important challenges. Most experiments are limited to one-dimensional chains or two-dimensional planes of ions, which constrain the scalability and functionality of quantum devices. Scientists have long dreamed of stacking these ions into three-dimensional structures, but this has been very difficult because it’s hard to keep the ions stable and well-controlled when arranged in more complex ways.

To address these challenges, an international collaboration of physicists from India, Austria, and the USA—including JILA and NIST Fellow Ana Maria Rey, along with NIST scientists Allison Carter and John Bollinger—proposed that tweaking the electric fields that trap the ions can create stable, multilayered structures, opening up exciting new possibilities for future quantum technologies. The researchers published their findings in Physical Review X.
 

Adam Kaufman, a JILA Fellow, NIST Physicist, and CU Boulder Physics Professor, has been awarded part of a $1.25 million grant from the Gordon and Betty Moore Foundation as part of its third annual cohort of Experimental Physics Investigators.

JILA and University of Colorado Boulder Physics graduate student Emma Nelson achieved notable recognition by securing 3rd place at the CU Boulder 2024 Innovation in Materials Symposium on August 15, 2024. Held at CU Boulder, this symposium is a significant platform for the materials research community, bringing together faculty, students, and industry professionals from CU Boulder and beyond. The event is dedicated to supporting interdisciplinary collaboration and furthering discussions in the field of materials science.

In the quiet halls of the Duane Physics building at the University of Colorado Boulder, two JILA researchers, postdoctoral research associate Catie LeDesma and graduate student Kendall Mehling, combine machine learning with atom interferometry to create the next generation of quantum sensors. Because these quantum sensors can be applied to various fields, from satellite navigation to measuring Earth’s composition, any advancement has major implications for numerous industries. 

As reported in a recent article preprint, the researchers successfully demonstrated how to build a quantum sensor using atoms moving through crystals made entirely of laser light. They applied accelerated forces to atoms along multiple directions and, using this sensor, measured the results, which closely matched values predicted by quantum theory. LeDesma and Mehling also showed that their device could accurately detect accelerations from just one run of their experiment, a feat that is very difficult to accomplish with traditional cold atom interferometry. 

Dr. Matthew Norcia, a member of JILA’s extensive alumni network, has been awarded the prestigious 2024 International Union of Pure and Applied Physics (IUPAP) Early Career Scientist Prize in Atomic, Molecular, and Optical Physics. The IUPAP Early Career Scientist Prize honors early career physicists for their exceptional contributions within specific subfields, offering recognition through a certificate, medal, and monetary award.

The JILA Association of Graduate Students (JAGS) proudly hosted its inaugural Graduate Student Seminar, marking the beginning of a promising seminar series to foster academic exchange, collaboration, and community within JILA. The event showcased the cutting-edge research conducted by three JILA graduate students, drawing an audience of over 70 graduate students, postdoctoral researchers, and staff members.

JILA postdoctoral researcher Jake Higgins, part of JILA and NIST Fellow and University of Colorado Boulder physics professor Jun Ye’s research group, has been awarded a coveted spot at the 2024 MIT Chemistry Future Faculty Symposium. This prestigious event will be held on August 12 and 13 on the MIT campus in Cambridge, MA, featuring some of the brightest early-career scientists poised to pursue academic careers.

JILA, a joint institute of the University of Colorado Boulder and the National Institute of Standards and Technology (NIST) hosted its inaugural workshop on recent technological and research advancements in quantum light from July 17 to 19, 2024. The conference was sponsored by the National Science Foundation (NSF)-funded JILA Physics Frontier Center (PFC), the CUbit Quantum Initiative, and laser company Toptica. 

The event invited speakers from various prestigious institutions, including Texas A&M University, the National Autonomous University of Mexico, Columbia University, Wake Forest University, Livermore National Lab, the University of Illinois Urbana-Champaign, Caltech, Oak Ridge National Lab, Cornell University, William & Mary, University College London, the University of Oregon, the University of Toronto, and the University of Virginia, along with multiple representatives from NIST.

JILA and NIST Fellow and University of Colorado Boulder Physics professor Jun Ye and his team at JILA, a collaboration between NIST and the University of Colorado Boulder, have developed an atomic clock of unprecedented precision and accuracy. This new clock uses an optical lattice to trap thousands of atoms with visible light waves, allowing for exact measurements. It promises vast improvements in fields such as space navigation, particle searches, and tests of fundamental theories like general relativity.