Precision Measurement
Functional materials—like molecular electronics, biomaterials, light-emitting diodes, or new photovoltaic materials—gain their electronic or photonic properties from complex and multifaceted interactions occurring at the elementary scales of their atomic or molecular constituents. In addition, the ability to control the functions of these materials through external stimuli , e.g., in the form of strong optical excitations, enables new properties in the materials, making them appealing for new technological applications. However, a major obstacle to overcome is the combination of the very fast time (billionths of a second) scales and the very small spatial (nanometer) scales which define the many-body interactions of the elementary excitations in the material which define its function. The extremely high time and spatial resolutions needed have been extremely difficult to achieve simultaneously. Many physicists have, therefore, struggled to visualize the interactions within these materials. In a paper recently published in Nature Communications, JILA Fellow Markus Raschke and his team report on a new ultrafast imaging technique that could solve this issue.
For JILA and NIST Fellows Ana Maria Rey and Jun Ye, one type of phenomena they are especially interested in observing are the interactions between light and atoms, especially those at the heart of the decay of an atom prepared in the excited state. Ye’s and Rey’s groups collaborated in a joint study, and were able to find an appropriate experimental setting where they were able to observe Pauli blocking of spontaneous emission by direct measurements of the excited state population.
Understanding ways to alter or even engineer spontaneous emission has been an intriguing topic in science. JILA Fellows Ana Maria Rey and James Thompson study ways to control light emission by placing atoms in an optical cavity, a resonator made of two mirrors between which light can bounce back and forth many times. Together, with JILA postdoc and first author Asier Piñeiro Orioli, they have predicted that when an array of multi-level atoms is placed in the cavity the atoms can all cooperate and collectively suppress their emission of light into the cavity.
Worldwide, many researchers are interested in controlling atomic and molecular interactions. This includes JILA and NIST fellows Jun Ye and Ana Maria Rey, both of whom have spent years researching interacting potassium-rubidium (KRb) molecules, which were originally created in a collaboration between Ye and the late Deborah Jin. In the newest collaboration between the experimental (Ye) and theory (Rey) groups, the researchers have developed a new way to control two-dimensional gaseous layers of molecules, publishing their exciting new results in the journal Science.
In a new paper published in the Journal of Physical Chemistry Letters, Jimenez and his team report a new experimental setup to search for the cause of a mysterious fluorescent signal that appears to be from entangled photon excitation. The results of their new experiments suggested that hot-band absorption (HBA) by the subject molecules, could be the potential culprit for this mysterious fluorescent signal, making it the prime suspect.
JILA and NIST Fellow Ana Maria Rey is to be inducted into the Colombian Academy of Exact, Physical and Natural Sciences (Academia Colombiana de Ciencias Exactas, Fisicas y Naturales). Fellow Ana Maria Rey has been inducted into the Colombian National Academy of Sciences.  Rey, is a Colombian-American physicist at the University of Colorado, Boulder who "studies the scientific interface between atomic, molecular and optical physics, condensed matter physics and quantum information science."
JILA physicists have measured Albert Einstein’s theory of general relativity, or more specifically, the effect called time dilation, at the smallest scale ever, showing that two tiny atomic clocks, separated by just a millimeter or the width of a sharp pencil tip, tick at different rates. The experiments, described in the Feb. 17 issue of Nature, suggest how to make atomic clocks 50 times more precise than today’s best designs and offer a route to perhaps revealing how relativity and gravity interact with quantum mechanics, a major quandary in physics.
U.S. Rep. Joe Neguse got a first-hand look at the future of ultrafast lasers, record-setting clocks, and quantum computers on the ÂÌñ»»ÆÞ campus. Neguse visited the university Thursday to tour facilities at JILA, a research partnership between ÂÌñ»»ÆÞ and the National Institute of Standards and Technology (NIST).
In the past month, the group has put up two new preprints.
- In the strontium experiment, we report the generation of entangled Bell states, prepared in optical clock qubits, whose phase coherence persists for more than 4 seconds. This uses a gate scheme proposed by M. Martin and I. Deutsch, based on Rydberg-mediated interactions. See the preprint here.
- On the Ytterbium experiment, we report our first results preparing, controlling, and detecting arrays of nuclear spin qubits of 171Yb. We observe high fidelity control with sub-microsecond pulse times. We also demonstrate low-entropy array preparation through deterministic loading techniques via the use of narrow-line transitions and Raman-sideband cooling to near the motional ground state. See the preprint here.
On December 8th, JILA and NIST Fellow Dr. Judah Levine spoke on his research into internet time service. Internet time service is based on atomic clock technology and is used to help set computer clocks and other devices. The virtual event was hosted by Executive Director Dan Powers of CO-Labs, a coalition of 30+ federally funded Colorado research labs, including JILA. Levine's talk was one in a series discussing the ROI of scientific research.