Joonhee Choi

All Publications

• Erasure cooling, control, and hyperentanglement of motion in optical tweezers. Science (New York, N.Y.) Shaw, A. L., Scholl, P., Finkelstein, R., Tsai, R. B., Choi, J., Endres, M. 2025; 388 (6749): 845-849

  Abstract

  Coherently controlling the motion of single atoms in optical tweezers would enable new applications in quantum information science. To demonstrate this, we first prepared atoms in their motional ground state using a species-agnostic cooling mechanism that converts motional excitations into erasures, errors with a known location. This cooling mechanism fundamentally outperforms idealized traditional sideband cooling, which we experimentally demonstrated. By coherently manipulating the resultant pure motional state, we performed mid-circuit readout and mid-circuit erasure detection through local shelving into motional superposition states. We lastly entangled the motion of two atoms in separate tweezers and generated hyperentanglement by preparing a simultaneous Bell state of motional and optical qubits, unlocking a large class of quantum operations with neutral atoms.

  View details for DOI 10.1126/science.adn2618

  View details for PubMedID 40403042

• Maximum Entropy Principle in Deep Thermalization and in Hilbert-Space Ergodicity PHYSICAL REVIEW X Mark, D. K., Surace, F., Elben, A., Shaw, A. L., Choi, J., Refael, G., Endres, M., Choi, S. 2024; 14 (4)

  View details for DOI 10.1103/PhysRevX.14.041051

  View details for Web of Science ID 001371940400001

• Single-Shot Readout and Weak Measurement of a Tin-Vacancy Qubit in Diamond PHYSICAL REVIEW X Rosenthal, E. I., Biswas, S., Scuri, G., Lee, H., Stein, A. J., Kleidermacher, H. C., Grzesik, J., Rugar, A. E., Aghaeimeibodi, S., Riedel, D., Titze, M., Bielejec, E. S., Choi, J., Anderson, C. P., Vu, J. 2024; 14 (4)

  View details for DOI 10.1103/PhysRevX.14.041008

  View details for Web of Science ID 001331721900001

• Universal quantum operations and ancilla-based read-out for tweezer clocks. Nature Finkelstein, R., Tsai, R. B., Sun, X., Scholl, P., Direkci, S., Gefen, T., Choi, J., Shaw, A. L., Endres, M. 2024; 634 (8033): 321-327

  Abstract

  Enhancing the precision of measurements by harnessing entanglement is a long-sought goal in quantum metrology1,2. Yet attaining the best sensitivity allowed by quantum theory in the presence of noise is an outstanding challenge, requiring optimal probe-state generation and read-out strategies3-7. Neutral-atom optical clocks8, which are the leading systems for measuring time, have shown recent progress in terms of entanglement generation9-11 but at present lack the control capabilities for realizing such schemes. Here we show universal quantum operations and ancilla-based read-out for ultranarrow optical transitions of neutral atoms. Our demonstration in a tweezer clock platform9,12-16 enables a circuit-based approach to quantum metrology with neutral-atom optical clocks. To this end, we demonstrate two-qubit entangling gates with 99.62(3)% fidelity-averaged over symmetric input states-through Rydberg interactions15,17,18 and dynamical connectivity19 for optical clock qubits, which we combine with local addressing16 to implement universally programmable quantum circuits. Using this approach, we generate a near-optimal entangled probe state1,4, a cascade of Greenberger-Horne-Zeilinger states of different sizes, and perform a dual-quadrature5 Greenberger-Horne-Zeilinger read-out. We also show repeated fast phase detection with non-destructive conditional reset of clock qubits and minimal dead time between repetitions by implementing ancilla-based quantum logic spectroscopy20 for neutral atoms. Finally, we extend this to multi-qubit parity checks and measurement-based, heralded, Bell-state preparation21-24. Our work lays the foundation for hybrid processor-clock devices with neutral atoms and more generally points to a future of practical applications for quantum processors linked with quantum sensors25.

  View details for DOI 10.1038/s41586-024-08005-8

  View details for PubMedID 39385054

  View details for PubMedCentralID 10567572

• Benchmarking highly entangled states on a 60-atom analogue quantum simulator. Nature Shaw, A. L., Chen, Z., Choi, J., Mark, D. K., Scholl, P., Finkelstein, R., Elben, A., Choi, S., Endres, M. 2024

  Abstract

  Quantum systems have entered a competitive regime in which classical computers must make approximations to represent highly entangled quantum states1,2. However, in this beyond-classically-exact regime, fidelity comparisons between quantum and classical systems have so far been limited to digital quantum devices2-5, and it remains unsolved how to estimate the actual entanglement content of experiments6. Here, we perform fidelity benchmarking and mixed-state entanglement estimation with a 60-atom analogue Rydberg quantum simulator, reaching a high-entanglement entropy regime in which exact classical simulation becomes impractical. Our benchmarking protocol involves extrapolation from comparisons against an approximate classical algorithm, introduced here, with varying entanglement limits. We then develop and demonstrate an estimator of the experimental mixed-state entanglement6, finding our experiment is competitive with state-of-the-art digital quantum devices performing random circuit evolution2-5. Finally, we compare the experimental fidelity against that achieved by various approximate classical algorithms, and find that only the algorithm we introduce is able to keep pace with the experiment on the classical hardware we use. Our results enable a new model for evaluating the ability of both analogue and digital quantum devices to generate entanglement in the beyond-classically-exact regime, and highlight the evolving divide between quantum and classical systems.

  View details for DOI 10.1038/s41586-024-07173-x

  View details for PubMedID 38509372

  View details for PubMedCentralID 10567575

• An elementary review on basic principles and developments of qubits for quantum computing. Nano convergence Chae, E., Choi, J., Kim, J. 2024; 11 (1): 11

  Abstract

  An elementary review on principles of qubits and their prospects for quantum computing is provided. Due to its rapid development, quantum computing has attracted considerable attention as a core technology for the next generation and has demonstrated its potential in simulations of exotic materials, molecular structures, and theoretical computer science. To achieve fully error-corrected quantum computers, building a logical qubit from multiple physical qubits is crucial. The number of physical qubits needed depends on their error rates, making error reduction in physical qubits vital. Numerous efforts to reduce errors are ongoing in both existing and emerging quantum systems. Here, the principle and development of qubits, as well as the current status of the field, are reviewed to provide information to researchers from various fields and give insights into this promising technology.

  View details for DOI 10.1186/s40580-024-00418-5

  View details for PubMedID 38498068

• Multi-ensemble metrology by programming local rotations with atom movements NATURE PHYSICS Shaw, A. L., Finkelstein, R., Tsai, R., Scholl, P., Yoon, T., Choi, J., Endres, M. 2024

  View details for DOI 10.1038/s41567-023-02323-w

  View details for Web of Science ID 001142522100001

• Erasure conversion in a high-fidelity Rydberg quantum simulator. Nature Scholl, P., Shaw, A. L., Tsai, R. B., Finkelstein, R., Choi, J., Endres, M. 2023; 622 (7982): 273-278

  Abstract

  Minimizing and understanding errors is critical for quantum science, both in noisy intermediate scale quantum (NISQ) devices1 and for the quest towards fault-tolerant quantum computation2,3. Rydberg arrays have emerged as a prominent platform in this context4 with impressive system sizes5,6 and proposals suggesting how error-correction thresholds could be significantly improved by detecting leakage errors with single-atom resolution7,8, a form of erasure error conversion9-12. However, two-qubit entanglement fidelities in Rydberg atom arrays13,14 have lagged behind competitors15,16 and this type of erasure conversion is yet to be realized for matter-based qubits in general. Here we demonstrate both erasure conversion and high-fidelity Bell state generation using a Rydberg quantum simulator5,6,17,18. When excising data with erasure errors observed via fast imaging of alkaline-earth atoms19-22, we achieve a Bell state fidelity of [Formula: see text], which improves to [Formula: see text] when correcting for remaining state-preparation errors. We further apply erasure conversion in a quantum simulation experiment for quasi-adiabatic preparation of long-range order across a quantum phase transition, and reveal the otherwise hidden impact of these errors on the simulation outcome. Our work demonstrates the capability for Rydberg-based entanglement to reach fidelities in the 0.999 regime, with higher fidelities a question of technical improvements, and shows how erasure conversion can be utilized in NISQ devices. These techniques could be translated directly to quantum-error-correction codes with the addition of long-lived qubits7,22-24.

  View details for DOI 10.1038/s41586-023-06516-4

  View details for PubMedID 37821592

  View details for PubMedCentralID PMC10567575

• Many-body cavity quantum electrodynamics with driven inhomogeneous emitters. Nature Lei, M., Fukumori, R., Rochman, J., Zhu, B., Endres, M., Choi, J., Faraon, A. 2023

  Abstract

  Quantum emitters coupled to optical resonators are quintessential systems for exploring fundamental phenomena in cavity quantum electrodynamics (cQED)1 and are commonly used in quantum devices acting as qubits, memories and transducers2. Many previous experimental cQED studies have focused on regimes in which a small number of identical emitters interact with a weak external drive3-6, such that the system can be described with simple, effective models. However, the dynamics of a disordered, many-body quantum system subject to a strong drive have not been fully explored, despite its importance and potential in quantum applications7-10. Here we study how a large, inhomogeneously broadened ensemble of solid-state emitters coupled with high cooperativity to a nanophotonic resonator behaves under strong excitation. We discover a sharp, collectively induced transparency (CIT) in the cavity reflection spectrum, resulting from quantum interference and collective response induced by the interplay between driven inhomogeneous emitters and cavity photons. Furthermore, coherent excitation within the CIT window leads to highly nonlinear optical emission, spanning from fast superradiance to slow subradiance11. These phenomena in the many-body cQED regime enable new mechanisms for achieving slow light12 and frequency referencing, pave a way towards solid-state superradiant lasers13 and inform the development of ensemble-based quantum interconnects9,10.

  View details for DOI 10.1038/s41586-023-05884-1

  View details for PubMedID 37100918