���Ҵ�ý�ƽ������

All atoms, molecules and materials are held together by a web of interactions between electrons and ions. In materials, tiny vibrations called phonons cause the positions of the ions to oscillate. How those phonons and electrons are coupled—or interact—determines a material’s properties. The Kapetyn-Murnane Group found that by using ultrafast laser pulses to excite the material, they can precisely study the interaction between electrons and the most important phonons in tantalum diselenide (1T-TaSe2)—and also manipulate it.

Our mobile communication networks are known as multiple access channels or MACS. Through this system, multiple users send data to a single tower, which then relays information to the correct receivers. These MACs have a fundamental limit on how much data they can handle. Through mathematical logic games, the Graeme Smith Group found that quantum entanglement could boost that fundamental limit.

Computer chips can’t get much smaller, but they can get faster. That means moving electrons around more quickly. To speed up computers and possibly enable other technologies, scientists want to use light to drive electric currents. The Nesbitt Lab studied gold nanostars and found a way to optically control currents at the nanoscale.

Fluorescence and dyes are great tools to study cells, proteins, bacteria, or DNA. But scientists need to efficiently sort out the glowing material from the non-glowing stuff in their samples. The Jimenez Lab and the JILA Electronics Shop teamed up to create an improved flow cytometry system which can not only sort fluorescent material faster, it can sort by fluorescence lifetime and brightness faster than a commercially available system.

By using optical tweezers, the Kaufman and Ye groups are exploring a new kind of optical atomic clock—one that can run measurements for more than half a minute, an unprecedented coherence time. Not only does this finding open new possibilities for precision measurement, it’s a starting point to engineer interactions between many coherent and carefully-controlled atoms.

Mechanical oscillators are crucial to developing quantum computers and quantum networks, but they have to fight against noise. Measuring the quantum movement of the oscillator not only reduces its noise, it perfectly displays the Heisenberg uncertainty principle.

Strontium is an incredible element at the center of quantum physics tools and studies—most famously optical atomic clocks. While strontium atoms have one very long-lived excited state (which lives more than 100 seconds), they also have nicely accessible excited states. Those excited states are easier to access, but they are short-lived. A new proposal from the Rey Theory Group suggests a way to reach a dark state where the atoms can live in this excited state forever, opening new opportunities for clock technologies.

Understanding how three atoms interact when they are close together is really tricky. For the past decade scientists agreed that there was a universal “sweet spot”, a range called the van der Waals universality. In that range, three atoms were close enough that their interactions could be explained with simpler two-body formulas. But the Cornell Group at JILA is testing the limits of van der Waals universality, which could help form a better predictive model for other atom species.

For the first time, JILA scientists are able to observe dynamical phase transitions in an out-of-equilibrium system. They also found that they could undo the dynamical changes, reversing the experiment to where it started, which has great implications for understanding how the quantum world behaves and acts as a model for superconductors.

Using a new silicon cavity, JILA’s Ye Group has built a laser with improved coherence to reduce the noise in two optical atomic clocks and achieve record high stability. Improving atomic clocks’ stability is crucial to evaluating the clock accuracy and using these tools for scientific experiments in physics and other disciplines.