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Atomic & Molecular Physics | Precision Measurement | Quantum Information Science & Technology
JILA and the University of Colorado Boulder Lead Pioneering Quantum Gravity Research with Heising-Simons Foundation Grant
Published: February 27, 2024

The Heising-Simons Foundation's Science program has announced a generous grant of $3 million over three years, aimed at bolstering theoretical and experimental research efforts to bridge the realms of Atomic, Molecular, and Optical (AMO) physics with quantum gravity theories. Among the recipients, a notable grant was awarded to a multi-investigator collaboration spearheaded by the University of Colorado Boulder (CU Boulder) and JILA, a joint institute of CU Boulder and the National Institute of Standards and Technology (NIST). 

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Investigators: Ana Maria Rey | Adam Kaufman | James Thompson
Precision Measurement | Quantum Information Science & Technology
Squeezing in the Dark of a Superradiant Roller Coaster
Published: February 19, 2024

While atomic clocks are already the most precise timekeeping devices in the universe, physicists are working hard to improve their accuracy even further. One way is by leveraging spin-squeezed states in clock atoms. Spin-squeezed states are entangled states in which particles in the system conspire to cancel their intrinsic quantum noise. These states, therefore, offer great opportunities for quantum-enhanced metrology since they allow for more precise measurements. Yet, spin-squeezed states in the desired optical transitions with little outside noise have been hard to prepare and maintain. 

One particular way to generate a spin-squeezed state, or squeezing, is by placing the clock atoms into an optical cavity, a set of mirrors where light can bounce back and forth many times. In the cavity, atoms can synchronize their photon emissions and emit a burst of light far brighter than from any one atom alone, a phenomenon referred to as superradiance. Depending on how superradiance is used, it can lead to entanglement, or alternatively, it can instead disrupt the desired quantum state. 

In a prior study, done in a collaboration between JILA and NIST Fellows, Ana Maria Rey and James Thompson, the researchers discovered that multilevel atoms (with more than two internal energy states) offer unique opportunities to harness superradiant emission by instead inducing the atoms to cancel each other’s emissions and remain dark. 

Now, reported in a pair of new papers published in Physical Review Letters and Physical Review A, Rey and her team discovered a method for how to not only create dark states in a cavity, but more importantly, make these states spin squeezed. Their findings could open remarkable opportunities for generating entangled clocks, which could push the frontier of quantum metrology in a fascinating way. 

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Investigators: Ana Maria Rey
Biophysics | Other
Probing Proton Pumping: New Findings on Protein Folding in bacteriorhodopsin (bR)
Published: February 05, 2024

When it comes to drug development, membrane proteins play a crucial role, with about 50% of drugs targeting these molecules. Understanding the function of these membrane proteins, which connect to the membranes of cells, is important for designing the next line of powerful drugs. To do this, scientists study model proteins, such as bacteriorhodopsin (bR), which, when triggered by light, pump protons across the membrane of cells. 

While bR has been studied for half a century, physicists have recently developed techniques to observe its folding mechanisms and energetics in the native environment of the cell’s lipid bilayer membrane. In a new study published by Proceedings of the National Academy of Sciences (PNAS), JILA and NIST Fellow Thomas Perkins and his team advanced these methods by combining atomic force microscopy (AFM), a conventional nanoscience measurement tool, with precisely timed light triggers to study the functionality of the protein function in real-time. 

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Investigators: Thomas Perkins
Precision Measurement | Quantum Information Science & Technology
Dipole-Dipole Interactions: Observing A New Clock Systematic Shift
Published: January 26, 2024

In a new study published in Science today, JILA and NIST (National Institute of Standards and Technology) Fellow and University of Colorado Boulder physics professor Jun Ye and his research team have taken a significant step in understanding the intricate and collective light-atom interactions within atomic clocks, the most precise clocks in the universe. 

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Investigators: Jun Ye
Precision Measurement | Quantum Information Science & Technology
B-C-S—Easy as I, II, III: Unveiling Dynamic Superconductivity
Published: January 24, 2024

In physics, scientists have been fascinated by the mysterious behavior of superconductors—materials that can conduct electricity with zero resistance when cooled to extremely low temperatures. Within these superconducting systems, electrons team up in “Cooper pairs” because they're attracted to each other due to vibrations in the material called phonons. 

As a thermodynamic phase of matter, superconductors typically exist in an equilibrium state. But recently, researchers at JILA became interested in kicking these materials into excited states and exploring the ensuing dynamics. As reported in a new Nature paper, the theory and experiment teams of JILA and NIST Fellows Ana Maria Rey and James K. Thompson, in collaboration with Prof. Robert Lewis-Swan at the University of Oklahoma, simulated superconductivity under such excited conditions using an atom-cavity system. 

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Investigators: Ana Maria Rey | James Thompson
Quantum Information Science & Technology
JILA Fellow Murray Holland awarded a Translational Quantum Research Seed Grant Administered by CU Boulder
Published: January 23, 2024

CU Boulder has proudly announced the winners of its prestigious 2023-2024 Translational Quantum Research Seed Grants, a crucial step in fostering quantum science and technology innovation. This year's selection includes JILA Fellow Murray Holland, a distinguished figure in the field of quantum physics, who has been recognized for his groundbreaking project, "Developing a strontium optical lattice atom interferometer."

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Investigators: Murray Holland
Laser Physics | Precision Measurement
Building on JILA’s Legacy of Laser Precision
Published: January 12, 2024

Within atomic and laser physics communities, scientist John “Jan” Hall is a key figure in the history of laser frequency stabilization and precision measurement using lasers. Hall's work revolved around understanding and manipulating stable lasers in ways that were revolutionary for their time. His work laid a technical foundation for measuring a tiny fractional distance change brought by a passing gravitational wave. His work in laser arrays awarded him the Nobel Prize in Physics in 2005

Building on this foundation, JILA and NIST Fellow Jun Ye and his team embarked on an ambitious journey to push the boundaries of precision measurement even further. This time, their focus turned to a specialized technique known as the Pound-Drever-Hall (PDH) method (developed by scientists R. V. Pound, Ronald Drever, and Jan Hall himself), which plays a large role in precision optical interferometry and laser frequency stabilization.

While physicists have used the PDH method for decades in ensuring their laser frequency is stably “locked” to an artificial or quantum reference, a limitation arising from the frequency modulation process itself, called residual amplitude modulation (RAM), can still affect the stability and accuracy of the laser’s measurements. 

In a new Optica paper, Ye’s team, working with JILA electronic staff member Ivan Ryger and Hall, describe implementing a new approach for the PDH method, reducing RAM to never-before-seen minimal levels while simultaneously making the system more robust and simpler. 

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Investigators: Jun Ye | John Hall
Atomic & Molecular Physics | Quantum Information Science & Technology
The Tale of Two Clocks: Advancing the Precision of Timekeeping
Published: January 11, 2024

Historically, JILA (a joint institute established by the National Institute of Standards and Technology (NIST) and the University of Colorado Boulder) has been a world leader in precision timekeeping using optical atomic clocks. These clocks harness the intrinsic properties of atoms to measure time with unparalleled precision and accuracy, representing a significant leap in our quest to quantify the most elusive of dimensions: time.

However, the precision of these clocks has fundamental limits, including the “noise floor,” which is affected by the “quantum projection noise” (QPN). “This comes from the spin-statistics of the individual qubits, the truly quantum nature of the atoms being probed,” elaborated JILA graduate student Maya Miklos. State-of-the-art clock comparisons, like those directed by JILA and NIST Fellow and University of Colorado Boulder Physics professor Jun Ye, are pushing ever closer to this fundamental noise floor limit. However, this limit can be circumvented by generating quantum entanglement in the atomic samples, boosting their stability.

Now, Ye’s team, in collaboration with JILA and NIST Fellow James K. Thompson, has used a specific process known as spin squeezing to generate quantum entanglement, resulting in an enhancement in clock performance operating at the 10-17stability level. Their novel experimental setup, published in Nature Physics, also allowed the researchers to directly compare two independent spin-squeezed ensembles to understand this level of precision in time measurement, a level never before reached with a spin-squeezed optical lattice clock. 

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Investigators: Jun Ye | James Thompson
Laser Physics | Precision Measurement | Quantum Information Science & Technology
Groundbreaking "Tabletop" Physics Experiments Receive Major Funding, with JILA and NIST Fellow Jun Ye Leading Key Project
Published: December 11, 2023

In an exciting turn for physics research, four major foundations have announced a collaborative funding effort for 11 pioneering "tabletop" experiments. The Gordon and Betty Moore Foundation, the Simons Foundation, the Alfred P. Sloan Foundation, and the John Templeton Foundation have come together, committing a total of $30 million. This unique initiative focuses on supporting experiments that, despite their relatively modest scale, are set to delve into areas often reserved for large-scale facilities.

Among the funded projects, each of which will receive up to five years of financial support, is a particularly notable experiment led by JILA and NIST Fellow Jun Ye and his research team. Known for his remarkable work in physics, Ye's project stands out for its ambition and innovative approach. The experiment involves the development of ultra-precise atomic clocks, which are expected to significantly advance our understanding of both quantum mechanics and general relativity.

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Investigators: Jun Ye
Precision Measurement | Quantum Information Science & Technology
JILA Graduate Student Anjun Chu Wins Prestigious Boeing Quantum Creators Prize
Published: November 17, 2023

Anjun Chu, a JILA graduate student, has been awarded the esteemed Boeing Quantum Creators Prize for 2023. This prestigious award, established by Boeing in 2021, celebrates early-career researchers who have significantly contributed to the advancement of quantum information science and engineering.

Chu, a member of the theory group led by JILA and NIST Fellow Ana Maria Rey, has distinguished himself through his groundbreaking research in quantum many-body dynamics. His work, focusing on spin systems and their multilevel extensions, has been vital in exploring quantum simulation and metrology in cutting-edge areas like optical lattice clocks and cavity QED systems.

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Investigators: Ana Maria Rey
Laser Physics | Precision Measurement | Quantum Information Science & Technology
Creating the “Goldilocks” Zone: Making Special-Shaped Light
Published: November 16, 2023

In a new study published in Scientific Reports, JILA Fellow and University of Colorado Boulder physics professor Andreas Becker and his team theorized a new method to produce extreme ultraviolet (EUV) and x-ray light with elliptical polarization, a special shape in which the direction of light waves’ oscillation is changing. This method could provide experimentalists with a simple technique to generate such light, which is beneficial for physicists to further understand the interactions between electrons in materials on the quantum level, paving the way for designing better electronic devices such as circuit boards, solar panels, and more.

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Investigators: Andreas Becker
Laser Physics | Nanoscience | Quantum Information Science & Technology
Unlocking the Secrets of Spin with High-Harmonic Probes
Published: November 10, 2023

Deep within every piece of magnetic material, electrons dance to the invisible tune of quantum mechanics. Their spins, akin to tiny atomic tops, dictate the magnetic behavior of the material they inhabit. This microscopic ballet is the cornerstone of magnetic phenomena, and it's these spins that a team of JILA researchers—headed by JILA Fellows and University of Colorado Boulder physics professors Margaret Murnane and Henry Kapteyn—has learned to control with remarkable precision, potentially redefining the future of electronics and data storage. 

As reported in a new Science Advances paper, the JILA team and collaborators from universities in Sweden, Greece, and Germany probed the spin dynamics within a special material known as a Heusler compound: a mixture of metals that behaves like a single magnetic material. For this study, the researchers utilized a compound of cobalt, manganese, and gallium, which behaved as a conductor for electrons whose spins were aligned upwards and as an insulator for electrons whose spins were aligned downwards.

Using a form of light called extreme ultraviolet high-harmonic generation (EUV HHG) as a probe, the researchers could track the re-orientations of the spins inside the compound after exciting it with a femtosecond laser, which caused the sample to change its magnetic properties. The key to accurately interpreting the spin re-orientations was the ability to tune the color of the EUV HHG probe light.
“In the past, people haven't done this color tuning of HHG,” explained co-first author and JILA graduate student Sinéad Ryan. “Usually, scientists only measured the signal at a few different colors, maybe one or two per magnetic element at most.” In a historic first, the JILA team tuned their EUV HHG light probe across the magnetic resonances of each element within the compound to track the spin changes with a precision down to femtoseconds (a quadrillionth of a second).

“On top of that, we also changed the laser excitation fluence, so we were changing how much power we used to manipulate the spins,” Ryan elaborated, highlighting that that step was also an experimental first for this type of research. By changing the power, the researchers could influence the spin changes within the compound.

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Investigators: Margaret Murnane | Henry Kapteyn
Laser Physics | Precision Measurement | Quantum Information Science & Technology
A Drum Sounding Both Hot and Cold
Published: November 08, 2023

When measuring minor changes for quantities like forces, magnetic fields, masses of small particles, or even gravitational waves, physicists use micro-mechanical resonators, which act like tuning forks, resonating at specific frequencies. Traditionally, it was assumed that the temperature across these devices is uniform. 

However, new research from JILA Fellow and University of Colorado Boulder physics professor Cindy Regal and her team, Dr. Ravid Shaniv and graduate student Chris Reetz has found that in specific scenarios, such as advanced studies looking at the interactions between light and mechanical objects, where the temperature might differ in various resonator parts, which lead to unexpected behaviors. Their observations, published in Physical Review Research, can potentially revolutionize the design of micro-mechanical resonators for quantum technology and precision sensing.

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Investigators: Cindy Regal
Biophysics | Chemical Physics | Precision Measurement
JILA Postdoctoral Researcher Vít Svoboda is Awarded a 2023 JUNIOR STAR project by the Czech Science Foundation
Published: November 06, 2023

Every year, the Czech Science Foundation (GCAR) funds several JUNIOR STAR projects focused on new research areas and building powerful collaborative teams. These projects are awarded to early-career scientists coming to the Czech Republic from other countries or with significant international experience. Each project is awarded CZK 25 million over the following five years.
This year, JILA postdoctoral researcher Vít Svoboda is one of the 17 awardees in the 2023 JUNIOR STAR cohort. 

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Investigators: David Nesbitt
Precision Measurement | Quantum Information Science & Technology
Making Use of Quantum Entanglement
Published: November 03, 2023

Quantum sensors help physicists understand the world better by measuring time passage, gravity fluctuations, and other effects at the tiniest scales. For example,  one quantum sensor, the LIGO gravitational wave detector, uses quantum entanglement (or the interdependence of quantum states between particles) within a laser beam to detect distance changes in gravitational waves up to one thousand times smaller than the width of a proton! 

LIGO isn’t the only quantum sensor harnessing the power of quantum entanglement. This is because entangled particles are generally more sensitive to specific parameters, giving more accurate measurements. 

While researchers can generate entanglement between particles, the entanglement may only be useful sometimes for sensing something of interest. To measure the “usefulness” of quantum entanglement for quantum sensing, physicists calculate a mathematical value, known as the Quantum Fisher Information (QFI), for their system. However, physicists have found that the more quantum states in the system, the harder it becomes to determine which QFI to calculate for each state. 

To overcome this challenge, JILA Fellow Murray Holland and his research team proposed an algorithm that uses the Quantum Fisher Information Matrix (QFIM), a set of mathematical values that can determine the usefulness of entangled states in a complicated system. 

Their results, published in Physical Review Letters as an Editor’s Suggestion, could offer significant benefits in developing the next generation of quantum sensors by acting as a type of “shortcut” to find the best measurements without needing a complicated model.

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Investigators: Murray Holland
Nanoscience | Precision Measurement | Quantum Information Science & Technology
Diamonds in the Quantum Rough: A Sparkling Breakthrough
Published: November 03, 2023

In quantum information science, many particles can act as “bits,” from individual atoms to photons. At JILA, researchers utilize these bits as “qubits,” storing and processing quantum 1s or 0s through a unique system. 

While many JILA Fellows focus on qubits found in nature, such as atoms and ions, JILA Associate Fellow and University of Colorado Boulder Assistant Professor of Physics Shuo Sun is taking a different approach by using “artificial atoms,” or semiconducting nanocrystals with unique electronic properties. By exploiting the atomic dynamics inside fabricated diamond crystals, physicists like Sun can produce a new type of qubit, known as a “solid-state qubit,” or an artificial atom.

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Investigators: Shuo Sun
Precision Measurement | Quantum Information Science & Technology
JILA and NIST Fellow Ana Maria Rey Receives 2023 Presidential Rank Award
Published: November 03, 2023

U.S. President Joe Biden has awarded 232 Senior Executive Service (SES), Senior-Level (SL), and Scientific and Professional (ST) members across 31 government agencies with the prestigious Presidential Rank Award. Of these individuals, JILA and NIST Fellow Ana Maria Rey has been recognized within the Department of Commerce for her work in precision measurement and quantum physics. 

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Investigators: Ana Maria Rey
Atomic & Molecular Physics | Laser Physics | Precision Measurement
Vortex Beam Microscopy: Supercharged Imaging at Short Wavelengths
Published: November 02, 2023

To study nanoscale patterns in tiny electronic or photonic components, a new method based on lensless imaging allows for near-perfect high-resolution microscopy. This is especially important at wavelengths shorter than ultraviolet, which can image with higher spatial resolution than visible light but where image-forming optics are imperfect. 

The most powerful form of lensless imaging is called ptychography, which works by scanning a laser-like beam across a sample, collecting the scattered light, and then using a computer algorithm to reconstruct an image of the sample. 

While ptychography can visualize many nanostructures, this special microscope has trouble analyzing samples with very regular, repeating patterns. This is because the scattered light does not change as a periodic sample is scanned, so the computer algorithm gets confused and cannot reconstruct a good image.

Taking on this challenge, recently graduated Ph.D. researchers Bin Wang and Nathan Brooks, working with JILA Fellows Margaret Murnane and Henry Kapteyn, developed a novel method that uses short-wavelength light with a special vortex or donut shape to scan these repeating surfaces, resulting in more varied diffraction patterns. This allowed the researchers to capture high-fidelity image reconstructions using this new approach, which they recently published in Optica. This result will also be highlighted in the Optica Magazine Optics and Photonics News in the annual highlights of Optics in 2023. 

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Investigators: Margaret Murnane | Henry Kapteyn
Precision Measurement | Quantum Information Science & Technology
JILA Graduate Students Qizhong Liang and Drew Morrill Win Colorado Photonics Industry Association Poster Contest
Published: October 23, 2023

Every year, the Colorado Photonics Industry Association (CPIA) holds a university meeting where students from several of Colorado's prominent universities present their work as a poster to an industry audience, followed by networking with potential employers. For students, it's an excellent opportunity to practice public speaking, share their current research projects, and find potential industry jobs. Each year, three students are awarded a cash prize for how well they communicate their research and the design of their poster. 

This year, JILA graduate students Qizhong Liang, from JILA and NIST Fellow Jun Ye's research group, and Drew Morrill, from JILA Fellows Margaret Murnane's and Henry Kapteyn's research group, have been awarded prizes for their poster presentations. 

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Investigators: Margaret Murnane | Henry Kapteyn | Jun Ye