Tweezing a New Kind of Atomic Clock
Atoms are tricky to control. They can zip around, or even tunnel out of their containment. In order for new precision measurement tools and quantum devices to work—and work well—scientists need to be able to control and manipulate atoms as precisely as possible.
That’s especially true for optical atomic clocks. In these clocks, a cold, excited atom’s electrons swing back and forth in what’s called a dipole, vibrating like a plucked string. Scientists rapidly count those swings with a laser,...
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 chemical reaction rates.
These super-chilly gases follow the seemingly counterintuitive rules of quantum mechanics, featuring exact units, or quanta, of energy and often-exotic motions. Thus, the ability to control chemical reactions in stable quantum gases could...
New JILA Tools ‘Turn On’ Quantum Gases of Ultracold Molecules
JILA researchers have developed tools to “turn on” quantum gases of ultracold molecules, gaining control of long-distance molecular interactions for potential applications such as encoding data for quantum computing and simulations.
The new scheme for nudging a molecular gas down to its lowest energy state, called quantum degeneracy, while suppressing chemical reactions that break up molecules finally makes it possible to explore exotic quantum states in which all the molecules interact with...
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.
Older atomic clocks operating at microwave frequencies have hunted for dark matter before, but this is the first time a newer clock, operating at higher optical frequencies, and an ultra-stable oscillator to ensure steady light waves have been harnessed to set more precise bounds on the search. The research is...
Measuring Spinning Donuts
Atoms are busy objects. Electrons whiz around the nucleus of the atom in attoseconds—quintillionths of a second. Those electrons can be orbiting farther out from the nucleus in an excited state, close to the nucleus in the lowest energy level called a ground state, or in a superposition—in two or more energy levels at once.
During ionization, some of those electrons will fly away from the atom. The direction and path those electrons take can tell scientists a lot about the state the atom was...
Electron Fly-Bys on the Chemical Reaction Pathway
In chemistry, the shape of a molecule matters. Different arrangements of the same molecule are called isomers, and scientists have spent decades pondering how that shape affects chemical reactions.
Molecules react, bond, and separate along a reaction pathway, twisting into different shapes and combinations before delivering their final products. Tracking that pathway, especially with two molecules that are otherwise identical, is extremely complicated for theorists and experimentalists alike—...
Now Hiring: The New Quantum Workforce
Scientists believe we are living in the Second Quantum Revolution, a period of rapid advances in technology based on discoveries in quantum science. Companies from giants like IBM and Google to small startups are eager to create and perfect these new quantum technologies—and that requires training a new kind of workforce.
Universities are currently adapting their curriculum to prepare their students to enter that workforce. But what exactly do these jobs require? What kind of work is out there...
The Rules of Photon Thunderdome
When it comes to photoluminescence, the rules for most materials are simple: shine a photon on the material, and one photon comes out. Other materials take some coaxing—shine two photons in and get a shorter wavelength photon out in a process called upconversion photoluminescence, or UCPL.
Many organic materials require a chemical sensitizer to get that upconversion photoluminescence—except for rubrene. This orange-tinted organic crystal can perform this upconversion photoluminescence process...
Total Ellipse of the SU(N)
There was something odd going on with the SU(N) fermions in the Ye Lab.
Normally, when a noninteracting Fermi gas of atoms is released from a trap, it expands isotropically. The atoms' pent-up kinetic energy sends them shooting away from each other in a ballistic expansion, forming a round, spherical pattern—that shape reflects the isotropic momentum distribution of the trapped gas. But with the SU(N) fermions, the Ye Group saw an anisotropic cloud—an ellipse, not a sphere.
"We were like, 'what...
Grabbing Proteins by the Tail
Cells are surrounded by a membrane containing carefully folded proteins. Those membrane proteins interact with the watery environment inside and outside the cell and the fatty environment of the membrane that keeps the inside and the outside of the cell separated.
That gives them an important role-they are how the inside of the cell talks to the outside of the cell, allowing viruses to attack or letting in medications to treat disease, said David Jacobson, a post-doc in the Perkins Group at...
What to Know if You’re Teaching Physics Labs Remotely
As the COVID-19 pandemic swept the world, professors had to pivot their lab courses quickly —sometimes in a matter of hours—to work remotely. Physicist and physics education researcher JILA Fellow Heather Lewandowski began getting questions from instructors around the country: how do you teach a laboratory class when you can’t be in the lab?
Lewandowski received an NSF RAPID Grant to answer this question, and did what scientists do best: she gathered data. She received 106 survey responses from...
Falling Dominos and an Army of Schrödinger’s Cats
Schrödinger’s Cat is one of the most famous thought experiments in quantum mechanics. Physicist Erwin Schrödinger’s thought experiment goes like this: suppose you have a cat sealed in a box with a contraption that may or may not go off to release a poison. The only way to confirm the cat’s fate is to open the box. Until the box is opened, the cat is both alive and dead.
Being in a superposition of two states at a time is an intrinsic property of quantum objects like atoms which, for example,...
The Sisyphean Task of Cooling Molecules
If you want to control the quantum world, it helps to make things really cold—like a few millionths of a degree above absolute zero. When atoms reach those ultracold temperatures, they slow down and scientists can better probe them and study their interactions.
Ultracold atoms have been well-explored for decades, and are the basis for precision metrology tools like atomic clocks. With dense collections of ultracold atoms, physicists have been able to study how atoms interact, leading to new...
Breathing Stars and the Most Beautiful Scalpel
Look at any material on an atomic level and you see a dynamic world of interconnected atoms and electrons. Negatively-charged electrons throughout the material swarm around the positively-charged ions, and the electrostatic force between them holds the material together.
At a nonzero temperature, the ions in the material vibrate around their equilibrium positions. Those collective vibrations are called phonons. As the ions move, the electron cloud—as well as its quantum properties—sways...
Playing Games with Quantum Entanglement
When you text your friends across the city, you aren’t sending messages directly to each other. Your phones send signals to the nearby cell phone tower, which takes all of these signals and redistributes them to the proper recipients.
This basic setup—multiple senders transmitting to one recipient—is known as a multiple access channel or MAC. And if you’ve had to wait impatiently for the network to send a five-minute video of your adorable cat, you know that MACs have a fundamental limit on how...
Guiding Electrons With Gold Nanostars
In nearly 80 years, computers have shrunk from electronic behemoths that filled 50-by-30-foot rooms to smartphones that fit in the palm of your hand.
That’s largely because transistors have shrunk down to the nanoscale—ten to a hundred billionths of a meter, which is a thousand times smaller than the width of a human hair. Those transistors control current in computer chips; they store the binary 1s and 0s your computer uses to process information. But recently scientists have run into a...
Sorting the Glow from the Flow
How do you find a single cell in sea of thousands? You make it glow.
Adding fluorescence helps track movement and changes in small things like cells, DNA, and bacteria. In a library of millions of cells or bacteria, flow cytometry sorts the glowing material you want to study from the non-glowing material.
In short, “it’s a fluorescence filter,” said Srijit Mukherjee, a graduate student in the Jimenez Lab at JILA.
With the help of JILA’s electronics shop and clean room, the Jimenez Lab has found...
Drumming to the Heisenberg Beat
“It's not noiseless but in principle it could be noiseless, and in practice it's approaching that limit.” - Robert Delaney
At JILA, scientists work on mechanical oscillators which are the size of a grain of salt. They may be tiny, but they are the heartbeat of quantum technology, and are currently a promising technology for networking quantum computers.
“If you push on a mechanical oscillator, it's going to move,” said Robert Delaney, a graduate student in the Lehnert Lab. The oscillator...
The Power of the Dark Side
"Dark states are stable and they do not decay. There is the possibility that they live forever." -Ana Maria Rey
How long can a unique atomic state live?
Atoms normally live in their ground state, where its electrons are sitting in their lowest possible orbits. But when the atoms are hit with some extra energy, their electrons are kicked into a higher energy level, orbiting further from the nucleus of the atom. That’s an excited state.
Long-lived excited states are appealing to physicists for...
How universal is universality?
“Atoms aren’t like protons. They’re full of pulleys and bells and whistles. Sometimes, those 'guts' matter.” - Eric Cornell
We understand pretty well how a single atom behaves. Two atoms interacting with each other? Still solvable. But it becomes exponentially more complicated to characterize how three atoms or particles interact with each other, explained Xin Xie, a graduate student in the Cornell Group at JILA.
“We study three-body physics because there are still mysteries in this interaction...
Counting the quietest sounds in the universe
In the Lehnert Lab at JILA, a qubit sits in a small copper box. The qubit itself would fit on your pinky nail. Using that qubit, graduate student Lucas Sletten can measure the quietest sound in the universe: individual phonons, the smallest particles that carry sound.
This qubit is designed to help us answer two simple but profound questions: Can we control sound in a quantum way? And if so, what can we do with sound that we can’t do with light?
“People have been curious about using sound as a...
Dancing through dynamical phase transitions in an out-of-equilibrium state
In physics, it’s always easier to study a system in equilibrium. A system in equilibrium is neat and orderly, everything in balance. But the real world is rarely so perfectly balanced.
“Life is out-of-equilibrium. The weather is out-of-equilibrium,” joked JILA Fellow Ana Maria Rey.
When things are out-of-equilibrium, it’s hard to study a phenomenon called dynamical phase transitions. Phase transitions are ubiquitous in nature, like when water turns into ice, Rey explained. A dynamical phase...
Keep it steady
"That's the difference between me sitting there and running my clock for an hour versus running my clock for ten hours." - Eric Oelker
Imagine trying to read a clock with hands that wobble. The worse the wobble, the more difficult it is to accurately read the time.
Optical atomic clocks have the same problem. An optical atomic clock uses a laser to measure the frequency of a collection of atoms in a lattice, the way a grandfather clock measures the frequency of a swinging pendulum to mark the...
DNA imaging, ready in five minutes
Ready in five
It turned out soaking the mica for too long was part of the problem. Plus, the DNA wasn’t able to equilibrate on the surface, resulting in the squished ball shapes rather than nice, separate strands. “If you let it sit for a long time, you're actually losing some of the surface charge and impurities in the water are being sucked down into the surface,” Perkins explained.
Here’s how the improved process works. The mica is pre-soaked in a concentrated nickel-salt solution, then...
The Fastest Vortex in the West
Hiding behind this optical croissant is a variety of unique physics.
What do whirlpools, black holes, hurricanes, Jupiter’s Great Red Spot, and the creamer you just put into your coffee cup have in common? All of these things exhibit vortex phenomena, in which a fluid (e.g., gas, liquid, plasma, etc.) circulates around a common axis. Vortices such as these abound in nature, and can be found in macroscopic systems like those described above, or in microscopic quantum systems. And we now know...