Research Highlights

Using the laser from the strontium optical atomic clock, physicists can generate multiple cat-state atoms quickly and easily.

The world is out-of-equilibrium, and JILA scientists are trying to learn what rules govern the dynamic systems that make our universe so complex and beautiful, from black holes to our living bodies.

Atoms could live in their excited states forever by reaching a dark state.

Using Feshbach resonance, physicists have found that they can control a dynamical phase transition in an out-of-equilibrium state. 

Getting a cluster state of perfectly entangled atoms for quantum computing may be easier using a tool in JILA's laboratory.

JILA researchers have proposed an experiment that would allow them to study rapid scrambling of quantum information, similar to what happens at the event horizon of a black hole. 

The chaos within a black hole scrambles information. Gravity tugs on time in tiny, discrete steps. A phantom-like presence pervades our universe, yet evades detection. These intangible phenomena may seem like mere conjectures of science fiction, but in reality, experimental comprehension is not far, in neither time nor space. Astronomical advances in quantum simulators and quantum sensors will likely be made within the decade, and the leading experiments for black holes, gravitons, and dark matter will be not in space, but in basements – sitting on tables, in a black room lit only by lasers.

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 small molecules, which are the most complex quantum systems that can currently be completely understood from the principles of quantum mechanics, will allow researchers to probe the quantum interactions of individual molecules with other molecules, investigate what happens to molecules during collisions, and study how molecules behave in chemical reactions. 

JILA and NIST scientists are hot on the trail of understanding quantum correlations (or entanglement) among groups of quantum particles such as atoms or ions. Such particles are the building blocks of larger and larger chunks of matter that make up the everyday world. Interestingly, correlated atoms and ions exhibit exotic behaviors and accomplish tasks that are impossible for noninteracting particles. Therefore, understanding how entanglement is generated in those systems is not only central to comprehending our world, but also advancing technology.

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 pancakes are analogs of electrons moving in solids, such studies are expected to shed light on the complex physics of metals and other solids. Credit:  The Ye group and Steve Burrows, JILA

The Rey and Ye groups discovered the strange rules of quantum baseball earlier this year. But now, quantum baseball games happen faster, and players (dipolar particles) are no longer free to move or stand wherever they want. Players must not only be stronger to jump and catch the balls (photons), but also more organized. At the same time, they must be good spinners. And, only a small amount of disorder is tolerated! The fast spinning of the players and their fixed positions have made quantum baseball a whole new game!

For a long time, there’s been a mystery concerning how tiny interactions between individual atoms could lead to really big changes in a whole cloud of independent-minded particles. The reason this behavior is mysterious is that the atoms interact weakly, and only when they are very close to each other. Yet, the atoms clear across the cloud seem to know when it’s time to participate in some big-deal quantum behavior such as simultaneously all changing the direction of their spins.

Exciting new theory from the Rey group reveals the profound effects of electron interactions on the flow of electric currents in metals. Controlling currents of strongly interacting electrons is critical to the development of tomorrow’s advanced microelectronics systems, including spintronics devices that will process data faster, use less power than today’s technology, and operate in conditions where quantum effects predominate.

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 quantum behavior of ultracold molecules and the atoms that form them. The Jin-Ye group, which runs the molecule factory, is now wrapping up operations in the old factory with experiments designed to improve operations in the ultramodern factory, which is close to completion.

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 working together. The players coordinate throwing and catching the balls. While this is going on, the balls can change the state of the players! Sometimes the balls even escape the quantum baseball game altogether and land on detectors in the laboratory.

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 motion is correlated with its spin. It occurs in everyday materials when negatively charged electrons move in response to electromagnetic fields inside a crystal.

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 quantum particles. By closely packing the molecules into a 3D optical lattice (a sort of “crystal of light”), the team was able to create the first “highly degenerate” gas of ultracold molecules.

The Regal and Rey groups have come up with a novel way to generate and propagate quantum entanglement [1], a key feature required for quantum computing. Quantum computing requires that bits of information called qubits be moved from one location to another, be available to interact in prescribed ways, and then be isolated for storage or subsequent interactions. The group showed that single neutral atoms carried in tiny traps called optical tweezers may be a promising technology for the job!

Scientists often use ultracold atoms to study the behavior of atoms and electrons in solids and liquids (a.k.a. condensed matter). Their goal is to uncover microscopic quantum behavior of these condensed matter systems and develop a controlled environment to model materials with new and advanced functionality.

When the Rey theory group first modeled a quantum system at JILA, it investigated the interactions of strontium atoms in the Ye group’s strontium-lattice clock. The quantum behavior of these collective interactions was relatively simple to model. However, the group has now successfully tackled some more complicated systems, including the ultracold polar KRb molecule experiment run by the Jin and Ye groups. In the process, the group has developed a new theory that will open the door to probing quantum spin behavior in real materials; atomic, molecular and optical gases; and other complex systems. The new theory promises important insights in different areas of physics, quantum information science, and biology.