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Opening new possibilities for quantum sensors, atomic clocks and tests of fundamental physics, JILA researchers have developed new ways of “entangling” or interlinking the properties of large numbers of particles. In the process they have devised ways to measure large groups of atoms more accurately even in disruptive, noisy environments.

The new techniques are described in a pair of papers published in Nature. JILA is a joint institute of the National Institute of Standards and Technology (NIST) and the University of Colorado Boulder.

JILA graduate student Yingchao Zhang, working with JILA Fellows Henry Kapteyn and Margaret Murnane and University of Colorado Boulder physics professor Rahul Nandkishore, utilized a powerful new method to precisely identify phonon interactions within quantum materials, the results of which were published in Nano Letters. Using ultraprecise, timed laser pulses, and extreme ultraviolet pulses, they measured the response times and saw precisely how the electrons and phonons interacted. This method paves the way for better control and manipulation of quantum materials.

In a new paper in The Astrophysical Journal, JILA Fellow Jason Dexter, graduate student Kirk Long, and other collaborators compared two main theoretical models for emission data for a specific quasar, 3C 273. Using these theoretical models, astrophysicists like Dexter can better understand how these quasars form and change over time.

In a recent Science paper, researchers led by JILA and NIST Fellow Jun Ye, along with collaborators JILA and NIST Fellow David Nesbitt, scientists from the University of Nevada, Reno, and Harvard University, observed novel ergodicity-breaking in C60, a highly symmetric molecule composed of 60 carbon atoms arranged on the vertices of a “soccer ball” pattern (with 20 hexagon faces and 12 pentagon faces). Their results revealed ergodicity breaking in the rotations of C60. Remarkably, they found that this ergodicity breaking occurs without symmetry breaking and can even turn on and off as the molecule spins faster and faster. Understanding ergodicity breaking can help scientists design better-optimized materials for energy and heat transfer.

In a new ACS Nano paper, JILA and NIST Fellow David Nesbitt, along with former graduate student Jacob Pettine and other collaborators, developed a new method for measuring the dynamics of specific particles known as “hot carriers,” as a function of both time and energy, unveiling detailed information that can be used to improve collection efficiencies.

To understand how EDTA binds to metal ions and water molecules, Madison Foreman, a former JILA graduate student in the Weber group, now a postdoctoral researcher at the University of California, Berkeley, Terry, and their supervisor, JILA Fellow J. Mathias Weber, studied the geometry of the EDTA binding site using a unique method that helped to isolate the molecules and their bound ions, allowing for more in-depth analyses of the binding interactions. They published a series of three papers on this topic. In their first paper, published in the Journal of Physical Chemistry A, they found that the size of the metal ion changes where it sits in the EDTA binding site, which affects other binding interactions, especially with water.

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.

To better understand heat transport at the nanoscale, JILA Fellows Margaret Murnane, Henry Kapteyn, and their research groups within the STROBE NSF Center, JILA, and the University of Colorado Boulder, created the first general analytical theory of nanoscale-confined heat transport, that can be used to engineer heat transport in 3D nanosystems—such as nanowires and nanomeshes—that are of great interest for next-generation energy-efficient devices. This discovery was published in NanoLetters.

Two-dimensional materials, like graphene and 2D semiconductors, are an area of physics that has been growing tremendously in the last decade. According to JILA graduate student Ben Whetten, “That’s because they exhibit new spin and electronic physical phenomena and have much promise to build new miniaturized photonic or semiconductor nanoscale devices.” Researchers like Whetten, and his advisor, JILA Fellow, and University of Colorado Boulder professor Markus Raschke, develop methods to image these materials, giving a better understanding of their inner workings. In a new paper in NanoLetters, Raschke, and his team extended their ultrafast microscope to see nanometer-sized imperfection(s) within a 2D semiconductor sample that created some surprising nonlinear optical effects.

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.