Bulletin of the American Physical Society
54th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 68, Number 7
Monday–Friday, June 5–9, 2023; Spokane, Washington
Session S10: Hybrid Quantum Systems |
Hide Abstracts |
Chair: Raghavendra Srinivas, University of Oxford/Oxford Ionics Room: 207 |
Thursday, June 8, 2023 10:30AM - 10:42AM Withdrawn |
S10.00001: State-Insensitive Trapping of Alkaline-Earth Atoms in a Nanofiber-Based Optical Dipole Trap Julio T Barreiro, G. Kestler, K. Ton, D. Filin, C. Cheung, P. Schneeweiss, T. Hoinkes, J. Volz, M. S Safronova, A. Rauschenbeutel Neutral atoms that are trapped and optically interfaced using the evanescent field surrounding optical nanofibers are a promising platform for developing quantum technologies and exploring fundamental science, such as quantum networks and many-body physics of interacting photons. Building on the successful advancements with trapped alkali atoms, here we demonstrate a state-insensitive, nanofiber-based optical dipole trap for strontium-88, an alkaline-earth atom, using the evanescent fields of an optical nanofiber. Employing a two-color, double magic-wavelength trapping scheme, we realize state-insensitive trapping for the kilohertz-wide intercombination transition, which we verify by performing high-resolution spectroscopy for an atom-surface distance of only 300 nm. This allows us to experimentally find and verify the state-insensitivity of the trap nearby a theoretically predicted magic wavelength of 435.827(25) nm. Given the non-magnetic ground state and low collisional scattering length of strontium-88, this work also lays the foundation for developing versatile and robust matter-wave atomtronic circuits over nanophotonic waveguides. |
Thursday, June 8, 2023 10:42AM - 10:54AM |
S10.00002: Enhanced state control and tunability at a Rydberg-atom superconducting circuit interface Luke L Brown, Stephen D Hogan Rydberg atoms are well suited to interfacing with superconducting microwave circuits for applications in hybrid quantum information processing. This is because of their large electric dipole transition moments at microwave frequencies, and long coherence times. Recently, helium Rydberg atoms were coupled to the 19.556 GHz mode of a niobium nitride coplanar waveguide resonator [1-3]. This resonator field drove the two photon 55s-56s transition between triplet Rydberg states. As will be presented in this talk, to extend this work, with the goal of accessing the single-photon strong-coupling regime of this hybrid cavity QED system, two additional nonresonant microwave fields have been incorporated into the experiment. These fields (1) null the polarizability of the 55s-56s transition so that the atoms can be located closer to the surface of the cryogenically cooled superconducting chip where the microwave field is stronger without detrimental effects from stray electric fields, and (2) allow the implementation of two-color microwave transitions to enhance the coupling strength of the atoms to the resonator. The resulting engineered helium Rydberg atom qubit is particularly well suited to applications in quantum technologies, including, e.g., microwave to optical photon conversion. |
Thursday, June 8, 2023 10:54AM - 11:06AM |
S10.00003: Towards a high cooperativity spin-mechanical system with NV centers and high-Q silicon nitride nanobeams Frankie Fung, Emma Rosenfeld, John D Schaefer, Trisha N Madhavan, Jin Chang, Jingkun Guo, Tony Zhou, Nabeel Aslam, Amir Yacoby, Simon Gröblacher, Mikhail D Lukin, Florain Goschin A hybrid spin-mechanical platform takes advantage of the properties of its constituents, such as the long-lived coherence of solid state spins and the high interfaceability of nanomechanical resonators. In particular, our platform consists of high-Q silicon nitride nanobeams coupled to NV centers inside nanopillar probes. We present measurements of the spin-mechanical coupling, as well as our current efforts to reach the high cooperativity regime via better positional control and even higher quality factors. We also discuss how our unique scanning probe geometry could enable programmable, long-range entanglement of distant spins via mechanical resonators. |
Thursday, June 8, 2023 11:06AM - 11:18AM |
S10.00004: Protocols for optical-microwave quantum transduction with quantum dots and surface-acoustic-wave cavities Alex Kwiatkowski, Akshay Seshadri, Ezad Shojaee, Poolad Imany, Zixuan Wang, Ryan A DeCrescent, Kevin L Silverman, Scott Glancy, Emanuel Knill We present analysis of protocols for optical-microwave quantum transduction mediated by an optical-frequency two-level-system and a microwave-frequency bosonic mode that are weakly coupled by a sigma_z hat{x} term. We focus on parameter regimes where the coupling rate is much smaller than the optical emission rate of the two-level-system, which is in turn smaller than the frequency of the bosonic mode. We demonstrate that quantum transduction is possible in this parameter regime, and investigate the dependence of the success rate on the device parameters. Our results will inform the design of quantum transduction devices consisting of, for example, a quantum dot located in a mechanical resonator. |
Thursday, June 8, 2023 11:18AM - 11:30AM |
S10.00005: Pulse based Variational Quantum Optimal Control for hybrid quantum computing Robert De Keijzer, Oliver Tse, Servaas Kokkelmans In this talk we discuss pulse based variational quantum algorithms (VQAs), which are designed to determine the ground state of a quantum mechanical system by combining classical and quantum hardware. In contrast to more standard gate based methods, pulse based methods aim to directly optimize the laser pulses interacting with the qubits, instead of using some parametrized gate based circuit. Using the mathematical formalism of optimal control, these laser pulses are optimized. This method has been used in quantum computing to optimize pulses for quantum gate implementations, but has only recently been proposed for full optimization in VQAs. Pulse based methods have several advantages over gate based methods such as faster state preparation, simpler implementation and more freedom in moving through the state space. |
Thursday, June 8, 2023 11:30AM - 11:42AM |
S10.00006: Improved scalable strategies for fast, high-fidelity, and long-distance entanglement distribution Stav Haldar, Pratik J Barge, Sumeet Khatri, Hwang Lee Near-term implementations of entanglement distribution in quantum networks must overcome current hardware limitations such as link losses, non-ideal measurements, and quantum memories with low coherence time. In this work, we show that the optimization of figures of merit such as the waiting time and fidelity for the end-to-end entanglement can be formulated in terms of a Markov decision process or MDP. An optimal protocol, or policy, for entanglement distribution can then be determined using reinforcement learning (RL). In particular, we simulate a near-term quantum network for entanglement distribution along a linear chain of nodes, both for homogeneous and inhomogeneous chains, and optimize the figures of merit using RL. We quantify the trade-off between minimizing the waiting time and maximizing the end-to-end link fidelity. We use a model-independent algorithm called Q-learning, in which the learning agent not only finds an improved policy but does so while simultaneously learning how the network itself is functioning. Our key finding is that, in certain parameter regimes, our RL-based optimization scheme provides policies that are better than previously known policies, such as the so-called "swap-as-soon-as-possible" policy. Our improved policies are characterized by dynamic, state-dependent cut-offs and collaboration between the nodes. Notably, we introduce in this work novel quantifiers for the collaboration between the nodes. These quantifiers tell us how much "global" knowledge of the network every node has, specifically, how much knowledge two distant nodes have of each other's states, as this is an important consideration for the practical implementation of our RL-based policies. Ultimately, RL-based methods are limited by the size of the networks that can be computationally simulated efficiently. The other main contribution of our work is to overcome this limitation. We introduce a new method for nesting RL-based policies for small repeater chains in order to obtain improved policies for large, long-distance repeater chains, thus paving a way for the scalable practical implementation of long-distance entanglement distribution. |
Thursday, June 8, 2023 11:42AM - 11:54AM |
S10.00007: A telecom quantum network node based on neutral atom arrays and nanophotonic crystal cavities. Shankar G Menon, Noah Glachman, Matteo Pompili, Yuzhou Chai, Dahlia Ghoshal, Kevin Singh, Alan M Dibos, Johannes Borregaard, Hannes Bernien A scalable quantum network architecture requires nodes that can generate high-fidelity remote entanglement, have telecom operation, processing capability, and the ability to interact with other qubit systems. Neutral atoms in optical tweezers have emerged as a promising platform that satisfies many of these requirements. Quantum simulation experiments and gate-based quantum computation have been demonstrated with neutral atom arrays, while entanglement distribution have been demonstrated with single atom nodes. However, integrating all these into a single platform that operates at telecom remains an outstanding challenge. Here, I will show our progress toward developing a telecom quantum network node using neutral atom arrays trapped next to nanophotonic crystal cavities. I will discuss our protocol for generating atom-photon entangled states, using excited state telecom transitions, and our experimental advances in achieving strong coupling between the atom and the cavity field. Our approach opens a direct pathway toward a scalable architecture by combining an array of atoms with an array of nanophotonic devices, and in connecting with other qubit systems. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700