Lasers for quantum: applications with requirements, and the future

Lorenzo M. Narducci, Eduardo Jaime Quel, Jorge R. Tredicce

Lute Maleki

Quantum sensors will play a major role in space science applications. This is because of the promising ability of these sensors to outperform their classical counterparts. Photonics is a major support technology for quantum sensors, but further developments are required to make components and systems possible for space applications. Photonic systems based on crystalline whispering gallery resonators are poised to address some of the needs of future sensors. A laser system based on this approach is being developed in support of Space Quantum Gravity Gradiometer using cesium atoms and is briefly described.

Xin Wang, Yuan Sun, Liang Liu

Quantum sensing with cold atoms is attracting more and more attention in the research frontier of quantum technologies. Isotropic laser cooling serves as a promising platform for this area and its many advantages include compactness, robustness, and not requiring fine-tuning of the optical alignment or magnetic field, which are particularly suitable for field and space applications. We have designed and demonstrated a special form of isotropic laser cooling system that is specifically tailored for the purpose of quantum sensing. In particular, the diffused cooling optical field is generated by hollow laser beam injection and the quality of detection process is improved. Moreover, the effective strength of diffused cooling laser is quantitatively deduced. We have carefully characterized the properties of our system, including the laser cooling performances with respect to different parameter settings, the influences of cooling laser polarization and repumping laser power, and radial atom density distribution. We anticipate that our progress will contribute to the future development of isotropic laser cooling for quantum sensing and quantum precision measurements.

S. G. Lipson, H. Lipson, David Stefan Tannhauser

Ran Liu, Xiaodong Yang, Yiheng Lin +2 more

Abstract We present a robust quantum optimal control framework for implementing fast entangling gates on ion-trap quantum processors. The framework leverages tailored laser pulses to drive the multiple vibrational sidebands of the ions to create phonon-mediated entangling gates and, unlike the state of the art, requires neither weak-coupling Lamb–Dicke approximation nor perturbation treatment. With the application of gradient-based optimal control, it enables finding amplitude- and phase-modulated laser control protocols that work without the Lamb–Dicke approximation, promising gate speeds on the order of microseconds comparable to the characteristic trap frequencies. Also, robustness requirements on the temperature of the ions and initial optical phase can be conveniently included to pursue high-quality fast gates against experimental imperfections. Our approach represents a step in speeding up quantum gates to achieve larger quantum circuits for quantum computation and simulation, and thus can find applications in near-future experiments.

Zhizhan Xu, Shengwu Xie, Shi-Yao Zhu +1 more