Bulletin of the American Physical Society
APS March Meeting 2023
Volume 68, Number 3
Las Vegas, Nevada (March 5-10)
Virtual (March 20-22); Time Zone: Pacific Time
Session G67: Neutral atom qubits and applicationsFocus
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Sponsoring Units: DQI Chair: Andrew Pocklington, University of Chicago Room: Room 412 |
Tuesday, March 7, 2023 11:30AM - 11:42AM |
G67.00001: Experimental Quantum Transport of Rydberg Excitations Kangheun Kim, Fan Yang, Jaewook Ahn Rydberg atom system is an emerging platform for quantum simulations due to its scalability and flexibility in its dynamics. One of the interesting dynamics, excitation transfer dynamics, was explored on Rydberg atoms previously with multiple Rydberg states [1,2], but this scheme requires additional effort on the initial state preparation. Recently, a simple approach only using a single type of Rydberg state was introduced by [3]. We here show the first experimental demonstration of hopping dynamics with this simple method by initializing a single atom from a neutral atom chain to the Rydberg state and applying the laser with the detuning far from both resonant and facilitation conditions [4]. We test the dynamics on the 3 and 4 atom chains and show the robustness of the dynamics to the collective dephasing mostly due to the laser phase noise. Endurance to the thermal noise of the negative detuning was also experimentally tested with respect to the positive detuning. At this moment our experiments show a 60% of success rate of excitation transfer, which is expected to be improved by adiabatically preparing the initial state. Our scheme is expected to be used to simulate real-world physics, for example, synthetic gauge fields generated with the multicolor expansion of this experiment will permit the exploration of rich physics related to nonuniform gauge fields [5]. |
Tuesday, March 7, 2023 11:42AM - 11:54AM |
G67.00002: Quantum operations in realistic neutral atom systems Gerard Pelegrí, Tomas Kozlej, Jonathan D Pritchard, Andrew J Daley In recent years, neutral atom arrays have emerged as one of the most promising platforms for quantum computation and simulation. In order to understand the current and future capabilities of these systems, it is important to employ numerical models which describe accurately detrimental effects on the fidelity of quantum operations such as decay of atomic states or laser phase noise. Here, we use efficient models that take into account these effects to study and optimize digital and analog operations in arrays of neutral atoms. Regarding digital gates, we present a robust protocol based on adiabatic rapid passage [1] for realizing high-fidelity multiqubit controlled phase gates. For currently available laser frequencies and powers, this scheme achieves fidelities F > 0.995 for three qubits and F > 0.99 for four qubits in ∼1.8 μs, with future technologies allowing access to higher fidelities. As for analog operations, we evaluate the impact of laser phase noise on the thermalization properties of adiabatically prepared crystalline states in one-dimensional neutral atom arrays. |
Tuesday, March 7, 2023 11:54AM - 12:06PM |
G67.00003: High-Fidelity, Low-Loss State Detection of Alkali Atoms in Optical Tweezers Matthew N Chow, Bethany J Little, Yuan-Yu Jau State detection often limits the performance of alkali atoms in optical tweezer platforms, which are widely used for studies in areas such as quantum computing, many-body physics, and quantum chemistry. Typical detection schemes use state-dependent atom loss, but this imposes a vacuum-dependent upper bound on readout fidelity, slows repetition rate, and complicates algorithms with mid-circuit measurement. An alternate atom retaining method is to collect state-dependent fluorescence photons. Until now, (without cavity enhancement) this technique has only been demonstrated to ≥ 1.2(2)% readout error (Fuhrmanek et al., 2011). |
Tuesday, March 7, 2023 12:06PM - 12:18PM |
G67.00004: Individual addressability for short-wavelength transitions through visible integrated photonics with free-space nonlinear conversion Thomas Propson, Thomas Propson, Ian Christen, Hamed Sattari, Gregory Choong, Adrian J Menssen, Amir H Ghadimi, Franco N C Wong, Dirk R Englund Integrated photonic devices offer a path to perform site-addressable quantum gates on thousands of atomic systems, pushing beyond the limits of bulk optical modulators. Integrated photonic platforms with transparency in the blue and ultraviolet—wavelengths required for many quantum gate protocols—are less developed than platforms for the visible or telecom. Here, we propose and implement a strategy to convert light from arrays of thin-film-lithium-niobate integrated photonic modulators to blue and ultraviolet wavelengths via sum-frequency generation with a strong pump beam. Using this strategy, we enable multi-channel, GHz modulation, from 300 nm to 900 nm with a single device. We discuss implications for Rydberg gates on neutral atom qubits. |
Tuesday, March 7, 2023 12:18PM - 12:30PM |
G67.00005: Optical tweezers throw and catch single atoms Hwang H Sub, Andrew Byun, Jaewook Ahn We present an experiment of single-atom throw-and-catch by optical tweezers. Optical tweezers are used to catch, accelerate and release (i.e., throw) single atoms, so that the atoms freely fly for a while, and then recapture and decelerate (i.e., catch) them. The successful throw-and-catch of single atom was recorded to be 94(3)% probability in experiments carried out with 35200(2700) m/s^2 acceleration. For the experiment, we used rubidium cold atoms [1]. The optical tweezers are first switched on to capture atoms in a magneto-optical trap, and then controlled to be accelerated, switched off and then back on, and finally decelerated, respectively, to throw, fly, and catch the atoms. The atoms are transported with a maximal speed of 0.5 m/s for a travel distance of 12.5 μm, and over a transportation efficiency of 90(3)%, even in the presences of other optical tweezers holding other atoms en route. This proof-of-principle experimental demonstration of flying atoms suggests possibilities of flying massive qubits, of which applications are promising in many quantum information technologies [2], such as quantum shuffle memory, non-photon quantum communication, and flying-qubit-based [3] quantum computing as well as in fundamental studies such as single-particle collisions. As an application of the flying atoms, we plan to explore Ryberg state qubit particle collisions. |
Tuesday, March 7, 2023 12:30PM - 12:42PM |
G67.00006: Symmetry protected state of Rydberg atoms as resources for universal measurement-based quantum computation Valentin Crépel Rydberg arrays have recently emerged as unique platforms for the simulation of strongly entangled states of matter. Combined with the high degree of control on each individual atoms that these systems offer, Rydberg arrays seem to fulfill all the requirements necessary for the realization of measurement based quantum computation. Two natural questions emerge from this observation: have entangled states allowing for universal measurement base quantum computation been realized? can the measurement driving the quantum computation on these states be efficiently realized in current experimental setups? |
Tuesday, March 7, 2023 12:42PM - 12:54PM |
G67.00007: Telecom-Compatible Neutral Atom Quantum Network Node Noah Glachman, Shankar G Menon, Matteo Pompili, Yuzhou Chai, Dahlia Ghoshal, Kevin Singh, Alan M Dibos, Johannes Borregaard, Hannes Bernien Neutral atom arrays in optical tweezers have emerged as a promising platform for quantum information processing due to their scalability, qubit indistinguishability, high-fidelity logic operations, and long coherence times. These same properties make neutral atoms ideal candidates for quantum network nodes. We have developed a protocol by which excited-state atomic transitions, strongly coupled to nanophotonic cavities, can be used as a direct telecom photonic interface for a quantum network node designed for long-distance entanglement generation. This telecom interface mitigates optical fiber losses and removes the need for frequency conversion, increasing the entanglement generation rate. This paves a path towards integrating a high quality, efficient telecom photonic interface with local quantum processors based on atom arrays. |
Tuesday, March 7, 2023 12:54PM - 1:06PM |
G67.00008: Local measurement of Rydberg atom graphs Andrew Byun, Hansub Hwang, Jaewook Ahn Rydberg atom systems are best represented by a mathematical graph with vertices denoting atoms and edges the nearest neighbor strong interactions. Here we use a single measurement qubit to probe the entire quantum dynamics of a massive Rydberg atom graph. This is in particular useful in Rydberg atom experiments, because the spatially measurable range of the Rydberg atoms is limited by the field of view on the focal plane of the optical detector (CCD, PMT, etc.), which results in not only forming a large-size Rydberg atom graph but also probing its dynamics technically challenging [1]. In experiments, we use a set of Rydberg atom graphs, which include a linear chain, a star graph, and a cyclic graph, and probe their dynamics in the nearest-neighbor blockade regime, by probing the time dynamics of the measurement qubit only. The result shows that the obtained Fourier-transformed dynamics are in good agreement with the corresponding many-body eigen-spectra. |
Tuesday, March 7, 2023 1:06PM - 1:42PM |
G67.00009: Atom arrays in an optical cavity Invited Speaker: Zhenjie Yan Atomic tweezer arrays coupled to optical cavities are a promising platform for quantum information processing due to the programmability of tweezer arrays and the light-matter interface provided by the cavity. When the cavity interacts with a single atom, it enables mid-circuit measurement: single-qubit readout during a multi-qubit quantum process. Measuring either atomic fluorescence or the transmission of light through the cavity, we achieve state measurement infidelities of 0.5% and find negligible decoherence on other atoms tens of microns away from the cavity center. When the cavity couples to multiple atoms collectively, it enhances the light-matter information transfer and facilitates long-range interactions among the atoms. Here we demonstrate precise control of the phase and amplitude of the cavity-atom coupling by positioning the tweezer sites within the cavity lattice. Illuminating the atom array with light propagating perpendicularly to the cavity axis, we observe both constructive and destructive collective Rayleigh scattering into the cavity field. These results are key steps toward observing cavity-mediated interactions between single atoms. |
Tuesday, March 7, 2023 1:42PM - 1:54PM |
G67.00010: Fast scrambling transition in sparse Clifford circuits Sridevi Kuriyattil, Andrew J Daley, Gregory Bentsen, Tomohiro Hashizume Quantum information scrambling is the process in which the initially localized quantum information gets delocalized due to many body dynamics present in the system. The question of efficient scrambling is especially relevant in experiments and noisy quantum simulators, where every applied gate is affected by noise and dissipation. In a local lattice, the underlying linear lightcone which governs the propagation of information limits the number of qubits that can be involved in any computation within the coherence time. By contrast, in systems with highly non-local interactions, it is possible for the information to spread exponentially rapidly. In this work, we study novel transitions between slow and fast scrambling regimes in Clifford circuits with tunable non-local sparse coupling. These models are experimentally accessible with 1D arrays of optically trapped neutral atoms, where non-local couplings are implemented by the rapid shuffling of atoms using optical tweezers. By tuning the sparse interactions and analyzing the degree to which information has been scrambled in the system using tripartite mutual information (TMI), we investigate this fast scrambling transition. |
Tuesday, March 7, 2023 1:54PM - 2:06PM |
G67.00011: Quantum dynamics of inter-graph Rydberg atom interactions MinHyuk Kim, Jaewook Ahn Recently there is tremendous and glowing interest in using Rydberg atom systems for quantum computing and quantum simulation, especially because of their large scales and complex configurations adequate for mathematical graphs [1-2]. This, as we consider here, opens a new possibility to study the interactions among Rydberg atom clusters, i.e., the inter-graph Rydberg atom interactions [3]. The simplest case is two Rydberg atom graphs of a fully blockade distance, which results in super-atom interactions, the interactions among N-level Rydberg atom graphs are qutric couplings (for N=3) and beyond (for N=4,5,etc), and the interaction between two layered Rydberg atom graphs provides, for example, the bi-layer many-body physics. We experimentally investigate the quantum dynamics of as-interacting Rydberg atom graphs, where, for example, over 10 graphs are prepared identically or differently from each other, so that up to total N~100 atoms can be simultaneously used in an area of 100 um x 100 um. We investigate the mesoscopic structural phase transitions by tuning the strength of the given inter-graph interactions. |
Tuesday, March 7, 2023 2:06PM - 2:18PM |
G67.00012: Quantum computing of 3-SAT problems using Rydberg atom arrays Seokho Jeong, MinHyuk Kim, Minki Hhan, Jaewook Ahn Seeking a quantum computation method for solving nondeterministic polynomial time (NP)-complete problems is of central interest in quantum information science. The 3-satisfiability problem (3-SAT) is one of the best-known NP-complete problems which cannot be solved time-effectively (i.e. in a polynomial time) unless P=NP. Here we present a proof-of-principle experimental demonstration of quantum mechanical computing for a set of instances of the 3-SAT (Satisfiability) problem. We use three-dimensional optical tweezer arrays to implement Rydberg atom graphs, which are Rydberg data atoms coupled by Rydberg quantum wires [1], in which the data atoms and wires are used for variables and complemented pairs of 3-SAT clauses. And their many-body ground states which are the maximal independent sets of the given graphs are reduced to the 3-SAT solutions. The experimental result shows that two-clause 3-SAT satisfiable probabilities, i.e., whether instance of the given graphs are satisfiable or not, are measured to be $87.1%$, $95.0%$ and $84.7%$, for one-, two- and three- inter-clause connections, respectively. This proof-of-principle experiment of 3-SAT suggests that an NP-complete problem can be efficiently solvable through a reduction among NP-complete problems. |
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