About the Ye Group

Quantum science and precision metrology — quantum matter probed with novel light source

Our research group explores the frontier of light-matter interactions. Precisely controlled lasers enable our communications with microscopically engineered quantum systems of atoms and molecules. By preparing matter in specific quantum states, and using probe light with the longest coherence time and precisely controlled waveform, we strive to make fundamental scientific discoveries and develop new enabling technologies.

The strongly integrated development of scientific vision and experimental tools has enabled us to advance important topics in precision measurement, quantum many-body physics, quantum metrology, ultrafast science, and quantum science in general. For example, we employ quantum gas of strontium atoms confined in optical lattices to achieve best performing atomic clocks and investigate novel quantum dynamics, combining quantum metrology and quantum simulation. We prepare molecules in quantum degenerate gases to engineer tunable Hamiltonians for correlated quantum phenomena. These quantum-state prepared molecules are also explored for test of fundamental physics and study of quantum chemistry. Stable lasers and optical frequency combs are extending precision spectroscopy and extreme nonlinear optics from mid infrared to extreme ultraviolet, providing novel probes for large quantum systems, trace detection for health and environment, and new spectroscopy opportunities for nuclear transitions.

Research Areas

  • Our group explores many facets of ultracold strontium (Sr), emphasizing precision measurement and quantum state engineering and manipulation of atomic states. The group has achieved exquisite technical control via precision stabilization of lasers and the realization of ultracold atoms in optical lattices. Early on, we focused on precision measurements of Sr electronic transitions, which occur at optical frequencies, to explore the possibility of developing an optical atomic clock.

  • Since 1999 and 2000, there has been a remarkable convergence of the fields of ultrafast optics, opti cal frequency metrology, and precision laser spectroscopy — a convergence that our lab was privileged to help facilitate. A remarkable transformation took place in these fields as unprecedented advances occurred in the control of optical phases ranging from the ultrashort (femtoseconds) to laboratory time scales (seconds). Today, a single-frequency continuous optical field can achieve a phase coherence time exceeding 1 s. This phase coherence can be precisely transferred to the electric waveform of an ultrafast pulse train!

  • Molecules cooled to ultralow temperatures provide fundamental new insights to molecular interaction dynamics in the quantum regime. In recent years, researchers from various scientific disciplines such as atomic, optical, and condensed matter physics, physical chemistry, and quantum science have started working together to explore many emergent research topics related to cold molecules, including cold chemistry, strongly correlated quantum systems, novel quantum phases, and precision measurement. The exceedingly low energy regimes for ultracold molecules represent a new playground for chemical physics where quantum behaviors play a dominant role in molecular interaction and dynamics. Unique and complex molecular energy structure provides new opportunities for sensitive probe of fundamental physics. The anisotropic and long-range dipolar interactions add new ingredients to strongly correlated and collective quantum dynamics in many-body systems.

Research Highlights

  • A representation of light scattering within the 3D gas, called the Fermi Sea

    Atomic Musical Chairs

    How atoms interact with light reflects some of the most basic principles in physics. On a quantum level, how atoms and light interact has been a topic of interest in the worldwide scientific community for many years. Light scattering is…
    Read More

  • Silhouettes of workforce

    Help Wanted: How to Build a Prepared and Diverse Quantum Workforce

    The second quantum revolution is underway, a period marked by significant advances in quantum technology, and huge discoveries within quantum science. From tech giants like Google and IBM, who build their own quantum computers, to…
    Read More

  • The dipolar interactions within a molecular gas

    Don’t React, Interact: Looking Into Inert Molecular Gases

    One of the major strengths of JILA are the frequent and ongoing collaborations between experimentalists and theorists, which have led to incredible discoveries in physics. One of these partnerships is between JILA Fellow John Bohn and…
    Read More

  • Model of frequency comb filtering breath molecules

    When Breath Becomes Data

    There are many ways to diagnose health conditions. One of the most common methods is blood testing. This sort of test can look for hundreds of different kinds of molecules in the body to determine if an individual has any diseases or…
    Read More

  • Model of eEDM

    Wiggles in Time: The Search for Dark Matter Continues

    In a new paper published in Physical Review Letters, JILA and NIST Fellows Eric Cornell, Jun Ye, and Konrad Lehnert developed a method for measuring a potential dark matter candidate, known as an axion-like particle. Axion-like…
    Read More

  • Model of the atomic clock comparisons

    NIST Team Compares 3 Top Atomic Clocks With Record Accuracy Over Both Fiber and Air

    In a significant advance toward the future redefinition of the international unit of time, the second, a research team led by the National Institute of Standards and Technology (NIST) has compared three of the world’s leading atomic…
    Read More

  • Model of the quantum gas pancake

    Molecules in Flat Lands: an Entanglement Paradise

    Entangled particles have always fascinated physicists, as measuring one entangled particle can result in  a change in another entangled particle, famously dismissed as “spooky action at a distance” by Einstein. By now, physicists…
    Read More

  • False-color image of a gas of potassium-rubidium polar molecules

    New JILA Tools ‘Turn On’ Quantum Gases of Ultracold Molecules

    For the first time, researchers can turn on an electric field to manipulate molecular interactions, get them to cool down further, and start to explore collective physics where all molecules are coupled to each other.


    Read More
  • Optical lattice

    JILA’s Electric ‘Knob’ Tunes Chemical Reaction Rates in Quantum Gas

    Building on their newfound ability to induce molecules in ultracold gases to interact with each other over long distances, JILA researchers have used an electric “knob” to influence molecular collisions and dramatically raise or lower…
    Read More

  • Cartoon clock looks for dark matter.

    Advanced Atomic Clock Makes a Better Dark Matter Detector

    JILA researchers have used a state-of-the-art atomic clock to narrow the search for elusive dark matter, an example of how continual improvements in clocks have value beyond timekeeping.


    Read More
  • SU(N) fermions display unique properties.

    Total Ellipse of the SU(N)

    A strangely shaped cloud of fermions revealed a record-fast way of cooling atoms for quantum devices.


    Read More
  • Gray molasses cooling in YO molecules

    The Sisyphean Task of Cooling Molecules

    Bringing molecules down to ultracold temperatures takes a mythic approach, but the Ye Group finds that their new scheme can hold up under tough conditions.


    Read More
  • optical tweezers holding atoms, connected by a clock

    Tweezing a New Kind of Atomic Clock

    Using optical tweezers, the Kaufman and Ye groups at JILA have achieved record coherence times, an important advance for optical clocks and quantum computing.


    Read More
  • Van der Waals universality between atoms

    How universal is universality?

    New research from the Cornell Group suggests that the van der Waals universality may have limitations.


    Read More
  • Silicon cavity constructed at JILA to reduce noise in optical atomic clock

    Keep it steady

    It's hard to read a clock with hands that wobble. The Ye Group has found a way to steady their optical atomic clock using a new cavity.


    Read More
  • Artist's Illustration of Buckyballs and Frequency Comb

    Buckyballs Play by Quantum Rules

    When the Ye group measured the total quantum state of buckyballs, we learned that this large molecule can play by full quantum rules. Specifically, this measurement resolved the rotational states of the…
    Read More

  • Illustration showing rubidium and potassium atoms.

    The First Quantum Degenerate Polar Molecules

    Understanding chemistry requires understanding both molecules and quantum physics. The former defines the start and end of chemical reactions, the latter dictates the dynamics in between. JILA researchers now have a better understanding…
    Read More

  • Thumbnail

    Turn it Up to 11 – The XUV Comb

    With the advent of the laser, the fuzzy bands glowing from atoms transformed into narrow lines of distinct color. These spectral lines became guiding beacons visible from the quantum frontier. More than a half century later, we stand at…
    Read More

  • Thumbnail

    Same Clock. New Perspective.

    We all know what a tenth of a second feels like. It’s a jiffy, a snap of the fingers, or a camera shutter click. But what does 14 billion years–the age of the universe–feel like? JILA’s atomic clock has the precision to measure the age…
    Read More

  • Thumbnail

    The Energetic Adolescence of Carbon Dioxide

    The reaction, at first glance, seems simple. Combustion engines, such as those in your car, form carbon monoxide (CO). Sunlight converts atmospheric water into a highly reactive hydroxyl radical (OH). And when CO and OH meet, one…
    Read More

  • Thumbnail

    And, The Answer Is . . . Still Round

    Why are we here? This is an age-old philosophical question. However, physicists like Will Cairncross, Dan Gresh and their advisors Eric Cornell and Jun Ye actually want to figure out out why people like us exist at all. If there had…
    Read More

  • Thumbnail

    The Clock that Changed the World

    Imagine A Future . . . The International Moon Station team is busy on the Moon’s surface using sensitive detectors of gravity and magnetic and electric fields looking for underground water-rich materials, iron-containing ores, and other…
    Read More

  • Thumbnail

    Quantum Adventures with Cold Molecules

    Researchers at JILA and around the world are starting a grand adventure of precisely controlling the internal and external quantum states of ultracold molecules after years of intense experimental and theoretical study. Such control of…
    Read More

  • Thumbnail

    Quantum Leaps

    In the Ye group’s new quantum simulation experiment, cold strontium atoms, which are analogs of electrons, are allowed to tunnel between the pancakes that confine the atoms with laser light. Because the atoms moving in an array of…
    Read More

  • Thumbnail

    Molecules at the Quantum Frontier

    Deborah Jin, Jun Ye, and their students wrote a review during the summer of 2016 for Nature Physics highlighting the accomplishments and future directions of the relatively new field of ultracold-molecule research. The field…
    Read More

  • Thumbnail

    The Radical Comb-Over

    Using frequency comb spectroscopy, the Ye group has directly observed transient intermediate steps in a chemical reaction that plays a key role in combustion, atmospheric chemistry, and chemistry in the interstellar medium. The group…
    Read More

  • Thumbnail

    Stalking the Wild Molecules

    The Ye group just solved a major problem for using molecular fingerprinting techniques to identify large, complex molecules: The researchers used an infrared (IR) frequency comb laser to identify four different large or complicated…
    Read More

  • Thumbnail

    The Ultramodern Molecule Factory: I. Doublons

    The old JILA molecule factory (built in 2002) produced the world’s first ultracold polar molecules [potassium-rubidium (KRb)] in 2008. The old factory has been used since then for ultracold chemistry investigations and studies of the…
    Read More

  • Thumbnail

    Quantum Baseball

    The Ye and Rey groups have discovered the strange rules of quantum baseball in which strontium (Sr) atoms are the players, and photons of light are the balls. The balls control the players by not only getting the atoms excited, but also…
    Read More

  • Thumbnail

    Creative Adventures in Coupling

    The Rey and Ye groups are in the midst of an extended collaboration on using the Ye group’s strontium (Sr) lattice clock for studies of spin-orbit coupling in pancake-like layers of cold Sr atoms. Spin-orbit coupling means an atom’s…
    Read More

  • Thumbnail

    A Thousand Splendid Pairs

    JILA’s cold molecule collaboration (Jin and Ye Groups, with theory support from the Rey Group) recently made a breakthrough in its efforts to use ultracold polar molecules to study the complex physics of large numbers of interacting…
    Read More

  • Thumbnail

    About Time

    The Ye group has just improved the accuracy of the world’s best optical atomic clock by another factor of three and set a new record for clock stability. The accuracy and stability of the improved strontium lattice optical clocks is now…
    Read More

  • Thumbnail

    A Bug’s Life

    The Ye Group recently investigated what first appeared to be a “bug” in an experiment and made an unexpected discovery about a new way to generate high-harmonic light using molecular gases rather than gases of noble atoms. Graduate…
    Read More

  • Thumbnail

    Atoms, Atoms, Frozen Tight in the Crystals of the Light, What Immortal Hand or Eye Could Frame Thy Fearful Symmetry?

    Symmetries described by SU(N) group theory made it possible for physicists in the 1950s to explain how quarks combine to make protons and neutrons and JILA theorists in 2013 to model the behavior of atoms inside a laser. Now, the Ye…
    Read More

  • Thumbnail

    Invisible Rulers of Light

    The Ye group has not only made two invisible rulers of extreme ultraviolet (XUV) light, but also figured out how to observe them with ordinary laboratory electronics. With this setup, the researchers were able to prove that the two…
    Read More

  • Thumbnail

    Sky Clocks and the World of Tomorrow

    Imagine a network of multiple clocks orbiting the Earth, not only reporting down to us, but also collaborating quantum mechanically among themselves to operate precisely in sync as a single global superclock, or world clock. The world…
    Read More

  • Thumbnail

    Dealing with Loss

    There’s exciting news from JILA’s ultracold molecule collaboration. The Jin, Ye, Holland, and Rey groups have come up with new theory (verified by experiment) that explains the suppression of chemical reactions between potassium-…
    Read More

  • Thumbnail

    A Clockwork Blue Takes the Gold

    JILA and NIST labs are well on the way to creating astonishingly accurate optical atomic clocks based on the neutral atoms strontium (Sr) and ytterbium (Yb). The new technologies are already capable of the most meticulous timekeeping in…
    Read More

  • Thumbnail

    The Dipolar Express

    Physicists wonder about some pretty strange things. For instance, one burning question is: How round is the electron? While the simplest picture of the electron is a perfect sphere, it is possible that it is instead shaped like an egg.…
    Read More

  • Thumbnail

    The Great Spin Swap

    Research associate Bo Yan and his colleagues recently observed spin exchanges in ultracold potassium-rubidium (KRb) molecules inside an optical lattice (a crystal of light formed by interacting laser beams). In solid materials, such…
    Read More

  • Thumbnail

    The Magnificent Quantum Laboratory

    Because quantum mechanics is crucial to understanding the behavior of everything in the Universe, one can understand key elements of the behavior of a neutron star by investigating the behavior of an atomic system in the laboratory.…
    Read More

  • Thumbnail

    Trapper Marmot and the Stone Cold Molecules

    The Ye group has opened a new gateway into the relatively unexplored terrain of ultracold chemistry. Research associate Matt Hummon, graduate students Mark Yeo and Alejandra Collopy, newly minted Ph.D. Ben Stuhl, Fellow Jun Ye, and a…
    Read More

  • Thumbnail

    The Big Chill

    The Ye and Bohn groups have made a major advance in the quest to prepare “real-world” molecules at ultracold temperatures. As recently reported in Nature, graduate students Ben Stuhl and Mark Yeo, research associate Matt Hummon…
    Read More

  • Thumbnail

    The Most Stable Clock in the World

    The world’s most stable optical atomic clock resides in the Ye lab in the basement of JILA’s S-Wing. The strontium-(Sr-)lattice clock is so stable that its frequency measurements don’t vary by more than 1 part in 100 quadrillion (1 x 10…
    Read More

  • Thumbnail

    New Silicon Cavity Silences Laser Noise

    Researchers from a German national laboratory, the Physikalisch-Technische Bundesanstalt (PTB) have collaborated with Fellow Jun Ye, Visiting Fellow Lisheng Chen (Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences…
    Read More

  • Thumbnail

    The Indomitable Ruler of Light

    The Ye group has created the world’s first “ruler of light” in the extreme ultraviolet (XUV). The new ruler is also known more formally as the XUV frequency comb. The comb consists of hundreds of equally spaced “colors” that function in…
    Read More

  • Thumbnail

    Ultracold Polar Molecules to the Rescue!

    Physicists would very much like to understand the physics underlying high-temperature superconductors. Such an understanding may lead to the design of room temperature superconductors for use in highly efficient and much lower-cost…
    Read More

  • Thumbnail

    The Cold Case

    The Ye group has built a cool new system for studying cold collisions between molecules. The system is far colder than a typical chemistry experiment that takes place at room temperature or hotter (300–500 K). But, it’s also much warmer…
    Read More

  • Thumbnail

    The Quantum Control Room

    In 2008, the Ye and Jin groups succeeded in making ultracold potassium-rubidium (KRb) molecules in their ground state (See “Redefining Chemistry at JILA” in the Spring 2010 issue of JILA Light & Matter). Their next goal was to…
    Read More

  • Thumbnail

    Strontium Clock Performance Skyrockets

    In 2008-2009, much to their amazement,researchers working on the Jun Ye group’s neutral Sr optical atomic clock discovered tiny frequency shifts caused by colliding fermions! They figured out that the clock laser was…
    Read More

  • Thumbnail

    The Quantum Modeling Agency

    “Nature is built quantum mechanically,” says Fellow Jun Ye, who wants to understand the connections between atoms and molecules in complex systems such as liquids and solids (aka condensed matter). He says that the whole Universe is…
    Read More

  • Thumbnail

    Deciphering Nature's Fingerprints

    Fellow Jun Ye’s group has enhanced the molecular fingerprinting technique with the development of a mid-infrared (mid-IR) frequency comb.  The new rapid-detection technique can now identify traces of a wider variety of molecules found…
    Read More

  • Thumbnail

    Redefining Chemistry at JILA

    Fellows Deborah Jin, Jun Ye, and John Bohn are exploring new scientific territory in cold-molecule chemistry. Experimentalists Jin and Ye and their colleagues can now manipulate, observe, and control ultralow-temperature potassium-…
    Read More

  • Thumbnail

    Freeze Frame

    The cold-molecule collaboration has developed a method for directly imaging ultracold ground-state KRb molecules. Their old method required the transfer of ultracold KRb molecules into a Feshbach state, which is sensitive to electric…
    Read More

  • Thumbnail

    Fermions in Collision?

    According to the laws of quantum mechanics, identical fermions at very low temperatures can’t collide. These unfriendly subatomic particles, atoms, or molecules simply will not share the same piece of real estate with an identical twin…
    Read More

  • Thumbnail

    The Right Stuff

    In the summer of 2008, Fellow Jun Ye spent a couple of months at CalTech, where he ran into another visiting professor, former JILA Fellow Peter Zoller. Zoller left JILA in 1994 to become Professor of Physics at the University of…
    Read More

  • Thumbnail

    A Quantum Leap for Precision Lasers

    To be the best they can be, optical atomic clocks need better clock lasers — lasers that remain phase coherent a hundred times longer than the very best conventional lasers. For instance, light from the clock laser in Fellow Jun Ye’s…
    Read More

  • Thumbnail

    Beams In Collision

    Last year the Ye group conducted an actual laboratory astrophysics experiment. Graduate students Brian Sawyer, Ben Stuhl, and Mark Yeo, research associate Dajun Wang, and Fellow Jun Ye fired cold hydroxyl (OH) radicals into a linear…
    Read More

  • Thumbnail

    Stalking the X-Ray Frequency Comb

    Fellow Jun Ye’s group is methodically working its way toward the creation of an X-Ray frequency comb. Recently, senior research associate Thomas Schibli, graduate student Dylan Yost, Fellow Jun Ye, and colleagues from IMRA America, Inc…
    Read More

  • Thumbnail

    Clock Talk

    By late 2006, Fellow Jun Ye’s clock team had raised the accuracy of its strontium (Sr)-lattice atomic clock to be just shy of that of the nation’s primary time and frequency standard, the NIST-F1 cesium (Cs) fountain clock. Graduate…
    Read More

  • Thumbnail

    The Gravity of the Situation

    What sort of experiment could detect the effects of quantum gravity, if it exists? Theories that go beyond the Standard Model of physics include a concept that links quantum interactions with gravity. Physicists would very much like to…
    Read More

  • Thumbnail

    Every Breath You Take

    With every breath you take, you breathe out carbon dioxide and roughly 1000 other different molecules. Some of these can signal the early onset of such diseases as asthma, cystic fibrosis, or cancer. Thanks to graduate student Mike…
    Read More

  • Thumbnail

    Lights, Magnets, Action!

    When the Jin and Ye group collaboration wanted to investigate the creation of stable ultracold polar molecules, the researchers initially decided to make ultracold KRb (potassium-rubidium) molecules and then study their collision…
    Read More

  • Thumbnail

    Exploring a Cold New World

    Researchers from the Ye, Bohn, and Greene groups are busy exploring a cold new world crawling with polar hydroxyl radical (OH) molecules. The JILA experimentalists have already discovered how to cool OH to “lukewarm” temperatures of 30…
    Read More

  • Thumbnail

    The South Broadway Shootout

    In the race to develop the world's best optical atomic clock, accuracy and precision are what count. Accuracy is the degree to which a measurement of time conforms to time's true value. Precision is a gauge of the exactness, or…
    Read More

  • Thumbnail

    Magic Light

    "In the right light, in the right time, everything is extraordinary," according to photographer Aaron Rose. He could have just as easily been describing precision optical spectroscopy experiments recently conducted by Research…
    Read More

  • Thumbnail

    Partnership in Time

    There's only one way to prove you've invented a better atomic clock: Come out on top of a comparison of your clock with one of the world's best atomic clocks: The NIST-F1 cesium fountain atomic clock, the nation's primary time and…
    Read More

  • Thumbnail

    Molecular Fingerprinting

    Science sleuths have a new and powerful method for identifying (and investigating) atoms and molecules, thanks to Graduate Student Mike Thorpe, Research Associate Kevin Moll, Senior Research Associate Jason Jones, Undergraduate Student…
    Read More

  • Thumbnail

    Time Traveling

    Scientists in Fellow Jun Ye's lab are developing a high-precision optical atomic clock linked to super-narrow optical transitions in ultracold, trapped strontium atoms. However, unless the new clock is portable (it is not) or…
    Read More

  • Thumbnail

    The Quest for Stability

    Fellow Jan Hall has been working on stabilizing the frequency of lasers since the 1960s. Now, he, JILA Research Associate Mark Notcutt, Long-Sheng Ma (currently at BIPM in France), and Fellow Jun Ye have devised an improved, compact,…
    Read More

  • Thumbnail

    The World's First UV Frequency Comb

    Jason Jones, Kevin Moll, Mike Thorpe, and Jun Ye have generated the world's first precise frequency comb in the extreme ultraviolet (EUV) using a combination of an ultrafast mode-locked laser and a precision high-finesse optical cavity…
    Read More

  • Thumbnail

    The Power of Mirrors

    Three years ago Jun Ye decided to apply an old idea for amplifying and stabilizing continuous-wave (cw) lasers to state-of-the-art ultrafast lasers. In 2002, Jason Jones, a postdoctoral fellow with Jun, analyzed whether the build-up…
    Read More

  • Thumbnail

    There's Strontium in the Clock

    A high-powered JILA collaboration led by JILA Fellows Jun Ye and Chris Greene is making important progress toward developing an ultrastable, high-accuracy optical atomic clock. The new optical clock design will use a variety of laser…
    Read More

Research Highlights

  • A representation of light scattering within the 3D gas, called the Fermi Sea

    Atomic Musical Chairs

    How atoms interact with light reflects some of the most basic principles in physics. On a quantum level, how atoms and light interact has been a topic of interest in the worldwide scientific community for many years. Light scattering is…
    Read More

  • Silhouettes of workforce

    Help Wanted: How to Build a Prepared and Diverse Quantum Workforce

    The second quantum revolution is underway, a period marked by significant advances in quantum technology, and huge discoveries within quantum science. From tech giants like Google and IBM, who build their own quantum computers, to…
    Read More

  • The dipolar interactions within a molecular gas

    Don’t React, Interact: Looking Into Inert Molecular Gases

    One of the major strengths of JILA are the frequent and ongoing collaborations between experimentalists and theorists, which have led to incredible discoveries in physics. One of these partnerships is between JILA Fellow John Bohn and…
    Read More

  • Model of frequency comb filtering breath molecules

    When Breath Becomes Data

    There are many ways to diagnose health conditions. One of the most common methods is blood testing. This sort of test can look for hundreds of different kinds of molecules in the body to determine if an individual has any diseases or…
    Read More

  • Model of eEDM

    Wiggles in Time: The Search for Dark Matter Continues

    In a new paper published in Physical Review Letters, JILA and NIST Fellows Eric Cornell, Jun Ye, and Konrad Lehnert developed a method for measuring a potential dark matter candidate, known as an axion-like particle. Axion-like…
    Read More

  • Model of the atomic clock comparisons

    NIST Team Compares 3 Top Atomic Clocks With Record Accuracy Over Both Fiber and Air

    In a significant advance toward the future redefinition of the international unit of time, the second, a research team led by the National Institute of Standards and Technology (NIST) has compared three of the world’s leading atomic…
    Read More

  • Model of the quantum gas pancake

    Molecules in Flat Lands: an Entanglement Paradise

    Entangled particles have always fascinated physicists, as measuring one entangled particle can result in  a change in another entangled particle, famously dismissed as “spooky action at a distance” by Einstein. By now, physicists…
    Read More

  • False-color image of a gas of potassium-rubidium polar molecules

    New JILA Tools ‘Turn On’ Quantum Gases of Ultracold Molecules

    For the first time, researchers can turn on an electric field to manipulate molecular interactions, get them to cool down further, and start to explore collective physics where all molecules are coupled to each other.


    Read More
  • Optical lattice

    JILA’s Electric ‘Knob’ Tunes Chemical Reaction Rates in Quantum Gas

    Building on their newfound ability to induce molecules in ultracold gases to interact with each other over long distances, JILA researchers have used an electric “knob” to influence molecular collisions and dramatically raise or lower…
    Read More

  • Cartoon clock looks for dark matter.

    Advanced Atomic Clock Makes a Better Dark Matter Detector

    JILA researchers have used a state-of-the-art atomic clock to narrow the search for elusive dark matter, an example of how continual improvements in clocks have value beyond timekeeping.


    Read More
  • SU(N) fermions display unique properties.

    Total Ellipse of the SU(N)

    A strangely shaped cloud of fermions revealed a record-fast way of cooling atoms for quantum devices.


    Read More
  • Gray molasses cooling in YO molecules

    The Sisyphean Task of Cooling Molecules

    Bringing molecules down to ultracold temperatures takes a mythic approach, but the Ye Group finds that their new scheme can hold up under tough conditions.


    Read More
  • optical tweezers holding atoms, connected by a clock

    Tweezing a New Kind of Atomic Clock

    Using optical tweezers, the Kaufman and Ye groups at JILA have achieved record coherence times, an important advance for optical clocks and quantum computing.


    Read More
  • Van der Waals universality between atoms

    How universal is universality?

    New research from the Cornell Group suggests that the van der Waals universality may have limitations.


    Read More
  • Silicon cavity constructed at JILA to reduce noise in optical atomic clock

    Keep it steady

    It's hard to read a clock with hands that wobble. The Ye Group has found a way to steady their optical atomic clock using a new cavity.


    Read More
  • Artist's Illustration of Buckyballs and Frequency Comb

    Buckyballs Play by Quantum Rules

    When the Ye group measured the total quantum state of buckyballs, we learned that this large molecule can play by full quantum rules. Specifically, this measurement resolved the rotational states of the…
    Read More

  • Illustration showing rubidium and potassium atoms.

    The First Quantum Degenerate Polar Molecules

    Understanding chemistry requires understanding both molecules and quantum physics. The former defines the start and end of chemical reactions, the latter dictates the dynamics in between. JILA researchers now have a better understanding…
    Read More

  • Thumbnail

    Turn it Up to 11 – The XUV Comb

    With the advent of the laser, the fuzzy bands glowing from atoms transformed into narrow lines of distinct color. These spectral lines became guiding beacons visible from the quantum frontier. More than a half century later, we stand at…
    Read More

  • Thumbnail

    Same Clock. New Perspective.

    We all know what a tenth of a second feels like. It’s a jiffy, a snap of the fingers, or a camera shutter click. But what does 14 billion years–the age of the universe–feel like? JILA’s atomic clock has the precision to measure the age…
    Read More

  • Thumbnail

    The Energetic Adolescence of Carbon Dioxide

    The reaction, at first glance, seems simple. Combustion engines, such as those in your car, form carbon monoxide (CO). Sunlight converts atmospheric water into a highly reactive hydroxyl radical (OH). And when CO and OH meet, one…
    Read More

  • Thumbnail

    And, The Answer Is . . . Still Round

    Why are we here? This is an age-old philosophical question. However, physicists like Will Cairncross, Dan Gresh and their advisors Eric Cornell and Jun Ye actually want to figure out out why people like us exist at all. If there had…
    Read More

  • Thumbnail

    The Clock that Changed the World

    Imagine A Future . . . The International Moon Station team is busy on the Moon’s surface using sensitive detectors of gravity and magnetic and electric fields looking for underground water-rich materials, iron-containing ores, and other…
    Read More

  • Thumbnail

    Quantum Adventures with Cold Molecules

    Researchers at JILA and around the world are starting a grand adventure of precisely controlling the internal and external quantum states of ultracold molecules after years of intense experimental and theoretical study. Such control of…
    Read More

  • Thumbnail

    Quantum Leaps

    In the Ye group’s new quantum simulation experiment, cold strontium atoms, which are analogs of electrons, are allowed to tunnel between the pancakes that confine the atoms with laser light. Because the atoms moving in an array of…
    Read More

  • Thumbnail

    Molecules at the Quantum Frontier

    Deborah Jin, Jun Ye, and their students wrote a review during the summer of 2016 for Nature Physics highlighting the accomplishments and future directions of the relatively new field of ultracold-molecule research. The field…
    Read More

  • Thumbnail

    The Radical Comb-Over

    Using frequency comb spectroscopy, the Ye group has directly observed transient intermediate steps in a chemical reaction that plays a key role in combustion, atmospheric chemistry, and chemistry in the interstellar medium. The group…
    Read More

  • Thumbnail

    Stalking the Wild Molecules

    The Ye group just solved a major problem for using molecular fingerprinting techniques to identify large, complex molecules: The researchers used an infrared (IR) frequency comb laser to identify four different large or complicated…
    Read More

  • Thumbnail

    The Ultramodern Molecule Factory: I. Doublons

    The old JILA molecule factory (built in 2002) produced the world’s first ultracold polar molecules [potassium-rubidium (KRb)] in 2008. The old factory has been used since then for ultracold chemistry investigations and studies of the…
    Read More

  • Thumbnail

    Quantum Baseball

    The Ye and Rey groups have discovered the strange rules of quantum baseball in which strontium (Sr) atoms are the players, and photons of light are the balls. The balls control the players by not only getting the atoms excited, but also…
    Read More

  • Thumbnail

    Creative Adventures in Coupling

    The Rey and Ye groups are in the midst of an extended collaboration on using the Ye group’s strontium (Sr) lattice clock for studies of spin-orbit coupling in pancake-like layers of cold Sr atoms. Spin-orbit coupling means an atom’s…
    Read More

  • Thumbnail

    A Thousand Splendid Pairs

    JILA’s cold molecule collaboration (Jin and Ye Groups, with theory support from the Rey Group) recently made a breakthrough in its efforts to use ultracold polar molecules to study the complex physics of large numbers of interacting…
    Read More

  • Thumbnail

    About Time

    The Ye group has just improved the accuracy of the world’s best optical atomic clock by another factor of three and set a new record for clock stability. The accuracy and stability of the improved strontium lattice optical clocks is now…
    Read More

  • Thumbnail

    A Bug’s Life

    The Ye Group recently investigated what first appeared to be a “bug” in an experiment and made an unexpected discovery about a new way to generate high-harmonic light using molecular gases rather than gases of noble atoms. Graduate…
    Read More

  • Thumbnail

    Atoms, Atoms, Frozen Tight in the Crystals of the Light, What Immortal Hand or Eye Could Frame Thy Fearful Symmetry?

    Symmetries described by SU(N) group theory made it possible for physicists in the 1950s to explain how quarks combine to make protons and neutrons and JILA theorists in 2013 to model the behavior of atoms inside a laser. Now, the Ye…
    Read More

  • Thumbnail

    Invisible Rulers of Light

    The Ye group has not only made two invisible rulers of extreme ultraviolet (XUV) light, but also figured out how to observe them with ordinary laboratory electronics. With this setup, the researchers were able to prove that the two…
    Read More

  • Thumbnail

    Sky Clocks and the World of Tomorrow

    Imagine a network of multiple clocks orbiting the Earth, not only reporting down to us, but also collaborating quantum mechanically among themselves to operate precisely in sync as a single global superclock, or world clock. The world…
    Read More

  • Thumbnail

    Dealing with Loss

    There’s exciting news from JILA’s ultracold molecule collaboration. The Jin, Ye, Holland, and Rey groups have come up with new theory (verified by experiment) that explains the suppression of chemical reactions between potassium-…
    Read More

  • Thumbnail

    A Clockwork Blue Takes the Gold

    JILA and NIST labs are well on the way to creating astonishingly accurate optical atomic clocks based on the neutral atoms strontium (Sr) and ytterbium (Yb). The new technologies are already capable of the most meticulous timekeeping in…
    Read More

  • Thumbnail

    The Dipolar Express

    Physicists wonder about some pretty strange things. For instance, one burning question is: How round is the electron? While the simplest picture of the electron is a perfect sphere, it is possible that it is instead shaped like an egg.…
    Read More

  • Thumbnail

    The Great Spin Swap

    Research associate Bo Yan and his colleagues recently observed spin exchanges in ultracold potassium-rubidium (KRb) molecules inside an optical lattice (a crystal of light formed by interacting laser beams). In solid materials, such…
    Read More

  • Thumbnail

    The Magnificent Quantum Laboratory

    Because quantum mechanics is crucial to understanding the behavior of everything in the Universe, one can understand key elements of the behavior of a neutron star by investigating the behavior of an atomic system in the laboratory.…
    Read More

  • Thumbnail

    Trapper Marmot and the Stone Cold Molecules

    The Ye group has opened a new gateway into the relatively unexplored terrain of ultracold chemistry. Research associate Matt Hummon, graduate students Mark Yeo and Alejandra Collopy, newly minted Ph.D. Ben Stuhl, Fellow Jun Ye, and a…
    Read More

  • Thumbnail

    The Big Chill

    The Ye and Bohn groups have made a major advance in the quest to prepare “real-world” molecules at ultracold temperatures. As recently reported in Nature, graduate students Ben Stuhl and Mark Yeo, research associate Matt Hummon…
    Read More

  • Thumbnail

    The Most Stable Clock in the World

    The world’s most stable optical atomic clock resides in the Ye lab in the basement of JILA’s S-Wing. The strontium-(Sr-)lattice clock is so stable that its frequency measurements don’t vary by more than 1 part in 100 quadrillion (1 x 10…
    Read More

  • Thumbnail

    New Silicon Cavity Silences Laser Noise

    Researchers from a German national laboratory, the Physikalisch-Technische Bundesanstalt (PTB) have collaborated with Fellow Jun Ye, Visiting Fellow Lisheng Chen (Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences…
    Read More

  • Thumbnail

    The Indomitable Ruler of Light

    The Ye group has created the world’s first “ruler of light” in the extreme ultraviolet (XUV). The new ruler is also known more formally as the XUV frequency comb. The comb consists of hundreds of equally spaced “colors” that function in…
    Read More

  • Thumbnail

    Ultracold Polar Molecules to the Rescue!

    Physicists would very much like to understand the physics underlying high-temperature superconductors. Such an understanding may lead to the design of room temperature superconductors for use in highly efficient and much lower-cost…
    Read More

  • Thumbnail

    The Cold Case

    The Ye group has built a cool new system for studying cold collisions between molecules. The system is far colder than a typical chemistry experiment that takes place at room temperature or hotter (300–500 K). But, it’s also much warmer…
    Read More

  • Thumbnail

    The Quantum Control Room

    In 2008, the Ye and Jin groups succeeded in making ultracold potassium-rubidium (KRb) molecules in their ground state (See “Redefining Chemistry at JILA” in the Spring 2010 issue of JILA Light & Matter). Their next goal was to…
    Read More

  • Thumbnail

    Strontium Clock Performance Skyrockets

    In 2008-2009, much to their amazement,researchers working on the Jun Ye group’s neutral Sr optical atomic clock discovered tiny frequency shifts caused by colliding fermions! They figured out that the clock laser was…
    Read More

  • Thumbnail

    The Quantum Modeling Agency

    “Nature is built quantum mechanically,” says Fellow Jun Ye, who wants to understand the connections between atoms and molecules in complex systems such as liquids and solids (aka condensed matter). He says that the whole Universe is…
    Read More

  • Thumbnail

    Deciphering Nature's Fingerprints

    Fellow Jun Ye’s group has enhanced the molecular fingerprinting technique with the development of a mid-infrared (mid-IR) frequency comb.  The new rapid-detection technique can now identify traces of a wider variety of molecules found…
    Read More

  • Thumbnail

    Redefining Chemistry at JILA

    Fellows Deborah Jin, Jun Ye, and John Bohn are exploring new scientific territory in cold-molecule chemistry. Experimentalists Jin and Ye and their colleagues can now manipulate, observe, and control ultralow-temperature potassium-…
    Read More

  • Thumbnail

    Freeze Frame

    The cold-molecule collaboration has developed a method for directly imaging ultracold ground-state KRb molecules. Their old method required the transfer of ultracold KRb molecules into a Feshbach state, which is sensitive to electric…
    Read More

  • Thumbnail

    Fermions in Collision?

    According to the laws of quantum mechanics, identical fermions at very low temperatures can’t collide. These unfriendly subatomic particles, atoms, or molecules simply will not share the same piece of real estate with an identical twin…
    Read More

  • Thumbnail

    The Right Stuff

    In the summer of 2008, Fellow Jun Ye spent a couple of months at CalTech, where he ran into another visiting professor, former JILA Fellow Peter Zoller. Zoller left JILA in 1994 to become Professor of Physics at the University of…
    Read More

  • Thumbnail

    A Quantum Leap for Precision Lasers

    To be the best they can be, optical atomic clocks need better clock lasers — lasers that remain phase coherent a hundred times longer than the very best conventional lasers. For instance, light from the clock laser in Fellow Jun Ye’s…
    Read More

  • Thumbnail

    Beams In Collision

    Last year the Ye group conducted an actual laboratory astrophysics experiment. Graduate students Brian Sawyer, Ben Stuhl, and Mark Yeo, research associate Dajun Wang, and Fellow Jun Ye fired cold hydroxyl (OH) radicals into a linear…
    Read More

  • Thumbnail

    Stalking the X-Ray Frequency Comb

    Fellow Jun Ye’s group is methodically working its way toward the creation of an X-Ray frequency comb. Recently, senior research associate Thomas Schibli, graduate student Dylan Yost, Fellow Jun Ye, and colleagues from IMRA America, Inc…
    Read More

  • Thumbnail

    Clock Talk

    By late 2006, Fellow Jun Ye’s clock team had raised the accuracy of its strontium (Sr)-lattice atomic clock to be just shy of that of the nation’s primary time and frequency standard, the NIST-F1 cesium (Cs) fountain clock. Graduate…
    Read More

  • Thumbnail

    The Gravity of the Situation

    What sort of experiment could detect the effects of quantum gravity, if it exists? Theories that go beyond the Standard Model of physics include a concept that links quantum interactions with gravity. Physicists would very much like to…
    Read More

  • Thumbnail

    Every Breath You Take

    With every breath you take, you breathe out carbon dioxide and roughly 1000 other different molecules. Some of these can signal the early onset of such diseases as asthma, cystic fibrosis, or cancer. Thanks to graduate student Mike…
    Read More

  • Thumbnail

    Lights, Magnets, Action!

    When the Jin and Ye group collaboration wanted to investigate the creation of stable ultracold polar molecules, the researchers initially decided to make ultracold KRb (potassium-rubidium) molecules and then study their collision…
    Read More

  • Thumbnail

    Exploring a Cold New World

    Researchers from the Ye, Bohn, and Greene groups are busy exploring a cold new world crawling with polar hydroxyl radical (OH) molecules. The JILA experimentalists have already discovered how to cool OH to “lukewarm” temperatures of 30…
    Read More

  • Thumbnail

    The South Broadway Shootout

    In the race to develop the world's best optical atomic clock, accuracy and precision are what count. Accuracy is the degree to which a measurement of time conforms to time's true value. Precision is a gauge of the exactness, or…
    Read More

  • Thumbnail

    Magic Light

    "In the right light, in the right time, everything is extraordinary," according to photographer Aaron Rose. He could have just as easily been describing precision optical spectroscopy experiments recently conducted by Research…
    Read More

  • Thumbnail

    Partnership in Time

    There's only one way to prove you've invented a better atomic clock: Come out on top of a comparison of your clock with one of the world's best atomic clocks: The NIST-F1 cesium fountain atomic clock, the nation's primary time and…
    Read More

  • Thumbnail

    Molecular Fingerprinting

    Science sleuths have a new and powerful method for identifying (and investigating) atoms and molecules, thanks to Graduate Student Mike Thorpe, Research Associate Kevin Moll, Senior Research Associate Jason Jones, Undergraduate Student…
    Read More

  • Thumbnail

    Time Traveling

    Scientists in Fellow Jun Ye's lab are developing a high-precision optical atomic clock linked to super-narrow optical transitions in ultracold, trapped strontium atoms. However, unless the new clock is portable (it is not) or…
    Read More

  • Thumbnail

    The Quest for Stability

    Fellow Jan Hall has been working on stabilizing the frequency of lasers since the 1960s. Now, he, JILA Research Associate Mark Notcutt, Long-Sheng Ma (currently at BIPM in France), and Fellow Jun Ye have devised an improved, compact,…
    Read More

  • Thumbnail

    The World's First UV Frequency Comb

    Jason Jones, Kevin Moll, Mike Thorpe, and Jun Ye have generated the world's first precise frequency comb in the extreme ultraviolet (EUV) using a combination of an ultrafast mode-locked laser and a precision high-finesse optical cavity…
    Read More

  • Thumbnail

    The Power of Mirrors

    Three years ago Jun Ye decided to apply an old idea for amplifying and stabilizing continuous-wave (cw) lasers to state-of-the-art ultrafast lasers. In 2002, Jason Jones, a postdoctoral fellow with Jun, analyzed whether the build-up…
    Read More

  • Thumbnail

    There's Strontium in the Clock

    A high-powered JILA collaboration led by JILA Fellows Jun Ye and Chris Greene is making important progress toward developing an ultrastable, high-accuracy optical atomic clock. The new optical clock design will use a variety of laser…
    Read More

In the Spotlight

Photo of Antonio Vigil
December 08, 2021: Recently Graduated JILA Undergraduate Antonio Vigil wins the CU Boulder "Outstanding Undergraduate"

Antonio Vigil, a recently graduated JILA undergraduate has been named an "Outstanding Undergraduate" by the College of Arts and Sciences at the University of Colorado Boulder. Vigil recently graduated summa cum laude after working for three years at JILA. 


Read More
Photo of Jun Ye
November 18, 2021: Jun Ye Wins the 2022 Herbert-Walther Award

JILA and NIST Fellow Jun Ye has been awarded the 2022 Herbert-Walther-Award from the German Physical Society and OPTICA (formerly OSA). This award recognizes distinguished contributions in quantum optics and atomic physics as well as leadership in the international scientific community.


Read More
Logo of  CO Office of Economic Development & Int'l Trade
November 16, 2021: JILA Featured in a new Quantum Documentary

CU Boulder innovators, JILA physicists, and university startup ColdQuanta are featured in a new film from the Colorado Office of Economic Development and International Trade (COEDIT) promoting Colorado's extensive quantum ecosystem.

The film interviews CUbit Director Jun Ye (Physics, JILA Fellow, NIST Fellow), Associate Research Professor Ana Maria Rey (Physics, JILA Fellow), and other members of CU Boulder's quantum community about the importance of quantum research and Colorado's prominence in the field. Dan Caruso, interim CEO of cold-atom quantum tech startup ColdQuanta—co-founded by Professor Dana Anderson (Physics, JILA)—is also extensively featured. 

Article is taken from the CUbit Quantum Initiative website. 


Read More
Photo of Jun Ye
November 16, 2021: Jun Ye Named 2021 Highly Cited Researcher

JILA and NIST Fellow Jun Ye has been named a 2021 Clarivate Highly Cited Researcher. This means that Ye is one of the 0.1%, of the world's researchers who receive this title. Clarivate™ is a data analytics company that identifies the world’s most influential researchers ─ the select few who have been most frequently cited by their peers over the last decade. Ye’s many published papers over the last year have been ranked in the top 1% by citations for field and year in the Web of Science™, according to Clarivate. Well done Dr. Ye! 


Read More

JILA Address

We are located at JILA: A joint institute of NIST and the University of Colorado Boulder.

Map | JILA Phone: 303-492-7789 | Address: 440 UCB, Boulder, CO 80309