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The process of developing a quantum computer has seen significant progress in the past 20 years. Quantum computers are designed to solve complex problems using the intricacies of quantum mechanics. These computers can also communicate with each other by using entangled photons (photons that have connected quantum states). As a result of this entanglement, quantum communication can provide a more secure form of communication, and has been seen as a promising method for the future of a more private and faster internet.

Qubits are a basic building block for quantum computers, but they’re also notoriously fragile—tricky to observe without erasing their information in the process. Now, new research from CU �Ǹ�Թ� and the National Institute of Standards and Technology (NIST) may be a leap forward for handling qubits with a light touch. In the study, a team of physicists demonstrated that it could read out the signals from a type of qubit called a superconducting qubit using laser light—and without destroying the qubit at the same time.

University of Colorado President Todd Saliman visited JILA this past week and toured the laboratories at the invitation of JILA and NIST Fellow Eric Cornell. Saliman was impressed by the research team and Fellows and applauded their work. “You are all working to change the world,” President Saliman said.

Our first paper from the Ytterbium tweezer project has been published in PRX! We show rapid control of the nuclear-spin qubit, T1 on 10 to 100 second timescales, and T2 times of several seconds. We also harness the narrow transitions in Yb to perform near-deterministic loading and ground-state cooling. See also follow up synopsis in Physics here.

JILA has a long history in quantum research, advancing the state of the art in the field as its Fellows study various quantum effects. One of these Fellowsis Adam Kaufman. Kaufman and his laboratory team work on quantum systems that are based on neutral atoms, investigating their capacities for quantum information storage and manipulation. The researchers utilize optical tweezers—arrays of highly focused laser beams which hold and move atoms—to study these systems. Optical tweezers allow researchers exquisite, single-particle experimental control. In a new paper published in Physical Review X, Kaufman and his team demonstrate that a specific isotope, ytterbium-171 (171Yb), has the capacity to store quantum information in decoherence-resistant (i.e., stable) nuclear qubits, allows for the ability to quickly manipulate the qubits, and finally, permits the production of such qubits in large, uniformly filled arrays.

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.

In January, we posted our first demonstration of a new concept for tweezer-programmable optical lattices. Using tweezers with spatial scale on the order of 400 nm, we can program the dynamics and Hamiltonian with single lattice site resolution. We use resolved-sideband cooling to prepare the atoms at extremely low temperatures. From these conditions, we demonstrate for the first time the implementation of a spatial search algorithm originally proposed by Childs and Goldstone. Andrew Childs collaborated with us on this project, and we expect interesting extensions down the line to multi-particle search algorithms.  

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.