Experimental Platforms
Our group makes a major effort in three different directions: first, the realization of a programmable quantum device using neutral atom arrays as a testbed for performing quantum simulation and benchmarking quantum protocols; second, the development of ultrasensitive nanoscale quantum sensors for precision measurements of electric and magnetic fields and temperature; third, the exploration of novel solid-state quantum platforms for fundamental physics and quantum information applications.
High-fidelity atom-array quantum simulator
The recent experiments related to quantum supremacy, demonstrating quantum computers can outperform conventional computers in certain computational tasks, have led to great interest in building even larger quantum systems and finding practical applications. However, the development of large-scale quantum simulators and computers is still in its infancy and is an experimentally challenging task. This is because entangled quantum states are extremely fragile and sensitive to environmental noise and control imperfections, leading to a significant reduction in fidelities of quantum operations in experiments. To address these challenges, a new platform based on alkali-earth atoms trapped in optical tweezer arrays has been investigated, which allows for high-fidelity quantum gate and entanglement operations that are comparable to, or even better than, other state-of-the-art platforms. Further, we have developed an experimentally efficient method to estimate the fidelity of large-scale quantum devices via a universality in many-body quantum chaos. Exploiting these unique capabilities, our group plans to scale up this system to a large number of atoms while maintaining high fidelity to explore various research problems in quantum information science.
References
High-fidelity entanglement and detection of alkaline-earth Rydberg atoms
I. S. Madjarov, J. P. Covey, A. L. Shaw, J. Choi, A. Kale, A. Cooper, H. Pichler, V. Schkolnik, J. R. Williams, and M. Endres
Nature Physics, 16, 857 (2020)
News & Views: A boost to Rydberg quantum computing
Preparing random states and benchmarking with many-body quantum chaos
J. Choi*, A. L. Shaw*, I. S. Madjarov, X. Xie, J. Covey, J. Cotler, D. K. Mark, H. Y. Huang, A. Kale, H. Pichler, F. G.S.L. Brandão, S. Choi, and M. Endres (*equal contribution)
Nature, 613, 468 (2023)
News & Views: They're so random
Scalable solid-state quantum register
Rare-earth ion qubits doped into nuclear spin-rich host crystals are versatile, multifunctional platforms with applications in quantum networking, simulation, and information processing due to their excellent optical and spin properties. Recently, in collaboration with the Faraon group at Caltech, we have demonstrated that a single 171Yb3+ ion qubit doped into yttrium orthovanadate (YVO4) can coherently interact with a local nuclear spin ensemble consisting of 51V5+ lattice ions, enabling the polarization and manipulation of the nuclear spin states in a collective manner. Specifically, the spin-wave like collective state of the nuclear spin ensemble can be employed as a long-lived quantum memory for the rare-earth ion qubit, playing a crucial role in quantum communication applications. In particular, polarized, dense nuclear spin ensembles are a promising platform for ultra-precise quantum sensing for probing new physics (e.g., searching for axion-like matter using solid-state nuclear magnetic resonance) and can also be used to explore quantum many-body dynamics that are inaccessible to classical simulation algorithms. Moreover, a strong coupling between a dense ensemble of rare-earth ions and a cavity field provides a unique testbed for studying cavity quantum electrodynamics (cavity QED) in the many-body regime. Motivated by these exciting future opportunities, our group plans on investigating a novel rare-earth-ion platform embedded in a nano-photonic cavity that utilizes large-scale, dense nuclear ensembles.
References
Nuclear spin-wave quantum register for a solid state qubit
A. Ruskuc, C.-J. Wu, J. Rochman, J. Choi† and A. Faraon† (†co-corresponding)
Nature, 602, 408 (2022)
News & Views: Clock qubit conducts nuclear ensemble
Many-body cavity quantum electrodynamics with driven inhomogeneous emitters
M. Lei*, R. Fukumori*, J. Rochman, B. Zhu, M. Endres, J. Choi†, and A. Faraon† (*equal contribution, †co-corresponding)
Nature, 617, 271 (2023)
Ultrasensitive nanoscale quantum sensors
We are also interested in developing ultrasensitive nanoscale quantum sensors for various applications! Details about near-term experiments will be posted soon.