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 W65: Quantum Information in AMO Physics II |
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Sponsoring Units: DAMOP Chair: Wenlu Shi, University of California, Irvine Room: Room 414 |
Thursday, March 9, 2023 3:00PM - 3:12PM |
W65.00001: Improvement of Squeezing using a Spatial Phase Modulator and Machine Learning jorge amari, Junnosuke Takai, Takuya Hirano Squeezed light is an important resource for quantum information processing using continuous variables. When pulsed light is used as a light source to generate squeezed light, sequential information processing can naturally be executed because a single pulse can be regarded as a single mode. In addition, using an optical waveguide as a nonlinear medium not only suppresses the gain induced diffraction [2] but also leads to photonic integration in future. |
Thursday, March 9, 2023 3:12PM - 3:24PM |
W65.00002: Non-Markovian dynamics of a driven qubit interacting with a structured environment Harsh Arora, Athreya Shankar, Samarth Hawaldar, Baladitya Suri A qubit in a fault tolerant quantum computing architecture couples to a structured environment. This necessitates going beyond the Markovian approximation and studying the non-Markovian dynamics of a driven qubit, since the drive is required for implementing gates. In this work we theoretically study a qubit interacting with a set of discrete bosonic modes using coherent state path integrals, leading to a representation in terms of Feynman diagrams. We formulate an iterative and, in principle, scalable approach which systematically includes corrections to the propagator's poles from higher order diagrams. We study the renormalisation strength of the qubit frequency due to non-Markovian noise and discuss the consequences for the scalability of quantum computers. Further, we calculate the amplitudes for multi-photon scattering for several distributions of bosonic modes. This enables us to investigate the modifications to the memory kernel of the qubit dynamics which arise due to higher-order environmental correlators. |
Thursday, March 9, 2023 3:24PM - 3:36PM |
W65.00003: Alligator photonic crystal nanoresonators for cavity QED in diamond Jean-Michel Borit, Daniel Riedel, Hope Lee, Yakub Grzesik, Jelena Vuckovic Diamond photonic crystal nanobeam cavities with group-IV color-center defects have recently emerged as a versatile platform for applications in quantum networks. However, due to limitations in current diamond processing techniques, existing cavity designs rarely allow for reliable fabrication at high quality factors. “Alligator” style designs promise more scalable fabrication, high Q factors and increased noise reduction. Despite this myriad of benefits, alligator nanobeams have remained largely unexplored. In this work, we present a systematic study of these novel design templates within diamond fabrication constraints. We report simulated quality factors with Q≈2.5×104 and mode volumes with Vmod∼3 (λ/nDia), thereby demonstrating the viability of alligator nanobeams for applications in quantum information science. |
Thursday, March 9, 2023 3:36PM - 3:48PM |
W65.00004: Frequency conversion through Rydberg states Erik G Brekke We demonstrate progress towards frequency conversion using four-wave mixing through Rydberg states in rubidium vapor. Excitation is accomplished through the intermediate 6p state using light at 420 nm generated through parametric four-wave mixing in combination with a 1015 nm laser. We demonstrate Electromagnetically Induced Transparency as a result of the Rydberg excitation transition. The application of microwaves then allows transitions between neighboring Rydberg states. This system is promising for potential six-wave mixing to accomplish microwave to optical frequency conversion |
Thursday, March 9, 2023 3:48PM - 4:00PM |
W65.00005: Entanglement in Photonic Crystal Cavities Angus J Crookes, Ben Yuen, Stephen M Hanham, Angela Demetriadou Quantum entanglement is an essential resource in quantum information science, such as in quantum computation and quantum cryptography. It has been realised in various environments, even at ambient conditions, but often complex experimental setups make them undesirable for use in distributed networks. Instead, optical cavities have been proposed as a key to harness both local and global entanglement across a network. Entanglement can be generated, processed, and stored locally in quantum nodes via light-matter strong coupling, although the integration of many proficient local nodes into a widespread network, connected by photons, remains an outstanding challenge. |
Thursday, March 9, 2023 4:00PM - 4:12PM |
W65.00006: Transcontinental entanglement distribution through satellite intermediary entanglement swapping. John Floyd, Spencer J Johnson, Paul G Kwiat Efficient transcontinental entanglement distribution is necessary to build a global quantum network. Without quantum repeaters, distribution through optical fibers is assailed by loss and scattering, limiting the network’s reach to around 100 kilometers. This distance can be greatly extended however, by transmitting photons through free space, where the transmission falls only as the reciprocal square of the propagation distance. Our experiment aims to prove the viability of one proposed satellite intermediary scheme: a down-link architecture using entanglement swapping. In this scheme, a satellite generates a pair of entangled photons that are spectrally unentangled – and therefore able to interfere with other photons. The satellite transmits the telecom pump and the entangled telecom photons down to a station on Earth’s surface; by doing so, both channels experience the same temporal delay due to Doppler shift and dispersion. The transmitted pump can then be collected, reamplified, and used to pump a second terrestrial entanglement source. Synchronizing and interfering the satellite and terrestrial entangled, telecom photons will then swap entanglement to the unused photons. We have implemented this by pumping non-degenerate entanglement sources, which produce daughter photons at 773 nm and 1588 nm, with a 520 nm pump, generated from third harmonic generation. |
Thursday, March 9, 2023 4:12PM - 4:24PM |
W65.00007: Highlights and designs on generation of telecom and VIS/IR degenerate polarization-entangled photons in different platforms Joyee Ghosh, Omshankar Saini, Vikash K Yadav Quantum entanglement is a key resource in a wide range of applications in quantum optics, quantum information and quantum communication (QC). Photonic qubits, where information is encoded in the quantum state of the photons are an ideal choice for some of these applications, due to their speed, robustness and ease of manipulation. In particular, entangled photon pairs, due to their high entanglement purity and relative simplicity of generation, are key elements for many QC protocols. Through spontaneous parametric down-conversion (SPDC), such photon pairs can be generated in all-fiber, wavelength division multiplexed (WDM) waveguide-based sources yielding telecom photons around 1550nm or in free-space-optical (FSO) nonlinear bulk crystals yielding visible/infrared (VIS/IR) photons around 800nm. In this work we will present our experimental highlights for two such sources developed for polarization entanglement. The broadband (>46nm) waveguide-based telecom photon source has a spectral brightness ∼2.5×107 pairs/s/mW/nm with a coincidence-to-accidental ratio (CAR)∼ 1322 that can be employed towards multiuser quantum key distribution. While the narrowband (<0.2nm) free-space, IR photon source has a brightness ~ 2x104 pairs/s/mW with a CAR ~1000 that has potential applications in long-distance FSO-QC systems. Covering these aspects, we will also present on-chip waveguide device designs for direct generation of postselection-free, multiple polarization-entangled biphoton states. |
Thursday, March 9, 2023 4:24PM - 4:36PM |
W65.00008: Spectroscopic Investigations of the Group IV spin qubits in Diamond Cathryn Michaels, Jesus Arjona Martinez, Ryan A Parker, Alexander Stramma, Kevin Chen, Isaac Harris, Carola M Purser, Martin Hayhurst Appel, Matthew Trusheim, Dorian A Gangloff, Dirk R Englund, Mete Atatüre Group-IV color centers in diamond are a promising light-matter interface for quantum networking devices [1,2] having demonstrated excellent optical properties [3] and long coherence times at millikelvin temperatures [4]. The negatively charged tin-vacancy center (SnV) is particularly interesting, as its large spin-orbit coupling offers strong protection against phonon dephasing and robust cyclicity of its optical transitions toward spin-photon-entanglement schemes [5]. Recently both full quantum control of the spin qubit [6] and high-quality intrinsic photonic properties [7] have been demonstrated, which combined with integration into photonic nanostructures [8] make the SnV a competitive spin-photon building block for quantum networks. Here we further investigate the spectroscopic properties of these promising spin qubits as a basis for entangled state generation. |
Thursday, March 9, 2023 4:36PM - 4:48PM |
W65.00009: High spectral brightness telecom compatible bichromatic entanglement source using warm atomic vapors Alexander N Craddock, Mehdi Namazi, Yang Wang, Mael Flament, Rourke Sekelsky Here, we present a high spectral brightness source of bichromatic, polarization entangled photons, based on spontaneous four-wave-mixing in a warm rubidium vapor. The source produces pairs with one of the photons in the telecom O-band, making it natively compatible with existing telecom infrastructure, and the other at 795-nm, near-resonant with the rubidium D1 line. Our source improves the entangled pair generation rate using a warm vapor by two orders of magnitude while maintaining high heralding efficiency, making it an ideal candidate for large scale telecom quantum networking demonstrations. |
Thursday, March 9, 2023 4:48PM - 5:00PM |
W65.00010: Towards Cavity-Enhanced Spectroscopy of Single Europium Ions in Yttria Nanocrystals Timon Eichhorn A promising approach for realizing scalable quantum registers lies in the efficient optical addressing of rare-earth ion spin qubits in a solid state host. We study Eu3+ ions doped into Y2O3 nanoparticles (NPs)[1] as a coherent qubit material and work towards efficient single ion detection by coupling their emission to a high-finesse fiber-based Fabry-Pérot microcavity [2,3]. A beneficial ratio of the narrow homogeneous line to the inhomogeneous broadening of the ion ensemble at temperatures below 10K makes it possible to spectrally address and readout single ions. The coherent control of the single ion 5D0 - 7F0 transition then permits optically driven single qubit operations on the Europium nuclear spin states. A Rydberg-blockade mechanism between ions within the same nanocrystal permits the implementation of a two-qubit CNOT gate to entangle spin qubits and perform quantum logic operations [4]. We observed fluorescence signals from small ensembles of Europium ions at cryogenic temperatures and measured cavity-enhanced optical lifetimes of half the free-space lifetime resulting in effective Purcell-factors of one. Considering the low branching ratio into the desired transition this amounts to a two-level Purcell-factor of 100. We will report on the progress towards single ion readout and control. |
Thursday, March 9, 2023 5:00PM - 5:12PM |
W65.00011: Low-frequency Spectral Data from Operator Dynamics Michael Flynn, Pieter W Claeys, Anatoli S Polkovnikov Recent works have pioneered the use of Lanczos algorithms to study operator dynamics in quantum many-body systems. The growth of operators, encoded in so-called Lanczos coefficients, is conjectured to be universal in systems which thermalize and relates directly to the high-frequency behavior of spectral functions. In this work, we show how low-frequency spectral properties can be extracted from Lanczos coefficients by using them to compute fidelity susceptibilities and approximate conserved quantities. The fidelity susceptibilities serve as a sharp measure of ergodicity, providing a low-frequency counterpart to the asymptotics of Lanczos coefficients. We apply our methods to one-dimensional spin systems and comment on distinctions between integrable and ergodic cases if time permits. Our results invite more concrete conjectures connecting Lanczos data to low-frequency responses, namely transport coefficients. |
Thursday, March 9, 2023 5:12PM - 5:24PM |
W65.00012: Schrödinger Cat States with High-Spin Nuclei Pragati Gupta, Arjen Vaartjes, Xi Yu, Andrea Morello, Barry C Sanders The ability to prepare Schrödinger cat states will play a vital role in the realization of quantum technology and its advantage over classical technology. However, the practical realization of cat states is severely limited by decoherence and particle loss in current platforms. Here, we show how to realize Schrödinger cat states with high-spin nuclei which host a coherent high-dimensional system that is well protected from the environment. This is achieved by designing a quantum control scheme to generate a coherent spin state with nuclear spin, which evolves to a cat state under quadrupole interaction, and is detected using generalized Ramsey interferometry. We design pulse sequences for electromagnetic control of high-spin nuclei to implement our scheme and discuss its practical feasibility via high-spin donors in solid-state devices. |
Thursday, March 9, 2023 5:24PM - 5:36PM |
W65.00013: Coupling Diamond Color Centers to Open Fiber-based Microcavities Yanik Herrmann, Julius Fischer, Julia M Brevoord, Colin Sauerzapf, Leonardo Wienhoven, Laurens Feije, Matteo Pasini, Matthew J Weaver, Maximilian T Ruf, Ronald Hanson Quantum networks [1] are promising for applications such as secure communication and distributed quantum computing. Diamond color center qubits like the nitrogen-vacancy center and the group IV-vacancy centers are excellent node candidates, but they have limited collectable coherent photon emission. Integration into a tunable, open microcavity can boost collection via the Purcell effect [2]. However, the sensitivity of such cavities to vibrations from the environment has so far been a challenge for developing the system further into a quantum network node, capable of entanglement generation. Here we present a new low temperature setup, which provides a low vibration level while maintaining flexibility over the cavity and fiber control. We will report on our most recent results on coupling color centers to the cavity. Such a system may speed up entanglement rates in present day networks by at least a factor of 100, a critical step towards large scale diamond-based quantum networks. |
Thursday, March 9, 2023 5:36PM - 5:48PM |
W65.00014: Simulating continuous symmetry models with discrete ones Alberto Giuseppe Catalano, Fabio Franchini, Salvatore Marco Giampaolo, Daria Brtan In the past few years it has been demonstrated that the introduction of a frustration of topological origin in one-dimensional spin-1/2 systems can strongly modify their behavior, e.g. by destroying order parameters or by changing the nature of quantum phase transitions. |
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