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IEEE International Conference on Group IV Photonics

作者： Tuhin Dey Augustus W. Arbogast Qian Meng Shamim Reza Aaron Muhowski Joshua Cooper Rachel S. Goldman Thales Borrely Seth R. Bank Mark A. Wistey Materials Science Engineering and Commercialization Program Texas State University San Marcos Texas USA Department of Physics Texas State University San Marcos Texas USA Department of Electrical and Computer Engineering University of Texas at Austin Austin Texas USA Department of Materials Science and Engineering University of Michigan Ann Arbor MI USA Departments of MSE Physics and EECS University of Michigan Ann Arbor MI USA Department of Physics and MSEC Program Texas State University San Marcos Texas USA

Device models show GeSn lasers are limited by weak electron and photon confinement. Adding carbon offers strong conduction band offsets, freeing SiGeSn layers for separate confinement heterostructures, reducing thresh...

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Distinguishing erbium dopants in Y2O3 by site symmetry: Ab initio theory of two spin-photon interfaces

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Physical Review Materials 2023年第12期7卷 126201-126201页

作者： Churna Bhandari Cüneyt Şahin Durga Paudyal Michael E. Flatté Ames National Laboratory Iowa State University Ames Iowa 50011 USA UNAM–National Nanotechnology Research Center and Institute of Materials Science and Nanotechnology Bilkent University Ankara Turkey Department of Physics and Astronomy University of Iowa Iowa City Iowa 52242 USA Department of Electrical and Computer Engineering Iowa State University Ames Iowa 50011 USA Department of Applied Physics Eindhoven University of Technology Eindhoven The Netherlands

We present a first-principles study of the defect formation and electronic structure of erbium (Er)–doped yttria (Y2O3). This is an emerging material for spin-photon interfaces in quantum information science due to the narrow-linewidth optical emission from Er dopants at standard telecommunication wavelengths and their potential for quantum memories and transducers. We calculate formation energies of neutral and negatively and positively charged Er dopants and find the charge-neutral configuration to be the most stable, consistent with experiment. Of the two substitutional sites of Er for Y, the C2 (more relevant for quantum memories) and C3i (more relevant for quantum transduction), we identify the former as possessing the lowest formation energy. The electronic properties are calculated using the Perdew-Burke-Ernzerhof functional along with the Hubbard U parameter and spin-orbit coupling, which yields a ∼6μB orbital and a ∼3μB spin magnetic moment, and 11 electrons in the Er 4f shell, confirming the formation of charge-neutral Er3+. This standard density functional theory approach underestimates the band gap of the host and lacks a first-principles justification for U. To overcome these issues we performed screened hybrid functional calculations, including a negative U for the 4f orbitals, with mixing (α) and screening (w) parameters. These produced robust electronic features with slight modifications in the band gap and the 4f splittings depending on the choice of tuning parameters. We also computed the many-particle electronic excitation energies and compared them with experimental values from photoluminescence.

关键词： First-principles calculations

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Dynamic Analysis of a Hyperchaotic Hyperjerk Circuit, FPGA Implementation and Its Application in RNG for Medical Images Encryption

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Transactions of the Indian National Academy of engineering 2022年第3期7卷 753-773页

作者： Feudjio, E. R. Tamba, V. Kamdoum Tagne, F. Kapche Tchendjeu, A. E. Tchahou Djatche, G. P. Biamou, A. L. Mbanda Fotsin, H. B. Research Unit of Automation and Applied Computer (URAIA) Department of Electrical Engineering IUT-FV Bandjoun University of Dschang Bandjoun Cameroon Research Unit of Condensed Matter Electronics and Signal Processing (URMACETS) Department of Physics University Of Dschang Dschang Cameroon Department of Computer Engineering National Polytechnic Institute University of Bamenda Bambili Cameroon

Nonlinear systems with high dimension have received considerable attention recently due to their possibility to exhibit complex dynamics including chaos, hyperchaos, pattern formation, self-organization, and other related dynamics. In this work, a novel four dimensional autonomous hyperchaotic hyperjerk circuit with hyperbolic sine and quintic nonlinearities is proposed and its corresponding dynamics is analyzed theoretically, numerically and experimentally. Using Kirchhoff’s laws, the state equations of the proposed hyperchaotic hyperjerk circuit are described. Some fundamental properties of the model including symmetry, dissipation, equilibrium points and their stability are examined. Bifurcation diagrams, Lyapunov exponent spectrum and phase portraits are plotted to point out the complex dynamical behaviors exhibited by the system. The numerical results are validated using PSpice-based circuit simulations and Field-programmable Gate Array (FPGA) implementations. In addition, to use the proposed hyperchaotic hyperjerk circuit for medical images encryption, a random number generator (RNG) is designed. The resulting random number generator (RNG) successfully passes the National Institute of Standards and Technology (NIST-800-22) statistical tests. This confirms that the proposed hyperchaotic hyperjerk circuit is effective in showing randomness. Finally, a medical images encryption algorithm is developed based on the generated random bits. The security performances analyses are performed and the results show that the proposed algorithm can effectively encrypt and decrypt medical images with better security performances.

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Ge2Sb2Se4 Te Phase Change Material Monolithic Platform for Integrated Photonics

Ge2Sb2Se4 Te Phase Change Material Monolithic Platform for I...

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Conference on Lasers and Electro-Optics (CLEO)

作者： Niloy Acharjee Hongyi Sun Siddhartha Ghosh Carlos A. Ríos Ocampo Institute for Research in Electronics & Applied Physics University of Maryland College Park MD USA Department of Electrical & Computer Engineering University of Maryland College Park MD USA Department of Materials Science & Engineering University of Maryland College Park MD USA Space Systems - Northrop Grumman 1 Space Park Blvd Redondo Beach CA USA

We demonstrate a monolithic Ge2Sb2Se4Te platform for tunable photonic integrated circuits. We fabricated and measured various on-chip components, including waveguides with preliminary 55.7±3.65 dB/cm propagation ... 详细信息

ISBN: (纸本)9798350369311

关键词： Phase change materials Waveguide components Refractive index Photonic integrated circuits Crystallization Propagation losses System-on-chip Electro-optical waveguides Optimization Photonics

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Miniaturizing Ultrastable Electromagnetic Oscillators: Sub-10−14 Frequency Instability from a Centimeter-Scale Fabry-Perot Cavity

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Physical Review applied 2022年第5期18卷 054054-054054页

作者： Charles A. McLemore Naijun Jin Megan L. Kelleher James P. Hendrie David Mason Yizhi Luo Dahyeon Lee Peter Rakich Scott A. Diddams Franklyn Quinlan Department of Physics University of Colorado Boulder Boulder Colorado 80309 USA National Institute of Standards and Technology Boulder Colorado 80305 USA Department of Applied Physics Yale University New Haven Connecticut 06520 USA Department of Electrical Computer and Energy Engineering University of Colorado Boulder Boulder Colorado 80309 USA

The best performance from compact, portable, and repeatably manufactured electromagnetic (EM) oscillators has for decades been built upon crystalline quartz resonators operating at radio frequencies. Such a source of frequency-stable EM waves has enabled a wide range of applications of significant technical and societal benefit, such as navigation and communication systems, distributed sensing, geodesy, and fundamental physics. However, meeting demands for increased measurement sensitivity requires pushing beyond a fractional frequency stability of 10−13, typical of the best ovenized quartz. To date, such performance has been available in the microwave domain only with the use of complex cryogenic systems, or in the optical domain at the expense of larger volume and weight. In either case, the size, weight, and power of state-of-the-art EM oscillators has relegated their use to laboratory experiments. Here we demonstrate the validity of a manufacturable, compact Fabry-Perot reference that improves upon all other centimeter-scale oscillators by more than a factor of 10, including those based on solid-state optical resonators as well as quartz. In a specific implementation, we show an 8 ml bonded assembly containing three vacuum-gap Fabry-Perot optical cavities with mirrors lithographically fabricated on a single substrate, each with quality factor exceeding 10 billion. A laser stabilized to one of the cavities exhibits thermal-noise-limited phase noise for offset frequencies ranging from 1 Hz to nearly 1 kHz, and fractional frequency stability of 7×10−15 at 1 s. Our advance with lithographically defined and microfabricated mirrors is validated by rigorous models, which highlight a path to oscillators with size comparable to ovenized quartz, but with significantly improved performance. For example, we predict sub-10−14 performance is readily attainable with a Fabry-Perot cavity volume less than 2 ml.

关键词： Atomic, optical & lattice clocks Laser applications Metrology Optical microcavities Optical sources & detectors Time & frequency standards Cavity resonators RF, microwave, & terahertz sources

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Qudit Dynamical Decoupling on a Superconducting Quantum Processor

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Physical Review Letters 2025年第5期134卷 050601-050601页

作者： Vinay Tripathi Noah Goss Arian Vezvaee Long B. Nguyen Irfan Siddiqi Daniel A. Lidar Department of Physics and Astronomy University of Southern California Los Angeles California 90089 USA Center for Quantum Information Science and Technology University of Southern California Los Angeles California 90089 USA Quantum Nanoelectronics Laboratory Department of Physics University of California at Berkeley Berkeley California 94720 USA Applied Math and Computational Research Division Lawrence Berkeley National Lab Berkeley California 94720 USA Department of Electrical and Computer Engineering University of Southern California Los Angeles California 90089 USA Department of Chemistry University of Southern California Los Angeles California 90089 USA

Multilevel qudit systems are increasingly being explored as alternatives to traditional qubit systems due to their denser information storage and processing potential. However, qudits are more susceptible to decoherence than qubits due to increased loss channels, noise sensitivity, and crosstalk. To address these challenges, we develop protocols for dynamical decoupling (DD) of qudit systems based on the Heisenberg-Weyl group. We implement and experimentally verify these DD protocols on a superconducting transmon processor that supports qudit operation based on qutrits (d=3) and ququarts (d=4). Specifically, we demonstrate single-qudit DD sequences to decouple qutrits and ququarts from system-bath-induced decoherence. We also introduce two-qudit DD sequences designed to suppress the detrimental cross-Kerr couplings between coupled qudits. This allows us to demonstrate a significant improvement in the fidelity of time-evolved qutrit Bell states. Our results highlight the utility of leveraging DD to enable scalable qudit-based quantum computing.

关键词： Qubits

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Ultrastable vacuum-gap Fabry-Pérot cavities operated in air

arXiv

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arXiv 2024年

作者： Liu, Yifan Jin, Naijun Lee, Dahyeon McLemore, Charles Nakamura, Takuma Kelleher, Megan Cheng, Haotian Schima, Susan Hoghooghi, Nazanin Diddams, Scott Rakich, Peter Quinlan, Franklyn Department of Physics University of Colorado Boulder BoulderCO80309 United States Time and Frequency Division National Institute of Standards and Technology BoulderCO80305 United States Department of Applied Physics Yale University New HavenCT06520 United States Electrical Computer & Energy Engineering University of Colorado Boulder BoulderCO80309 United States

We demonstrate a vacuum-gap ultrastable optical reference cavity that does not require a vacuum enclosure. Our simple method of optical contact bonding in a vacuum environment allows for cavity operation in air while maintaining vacuum between the cavity mirrors. Vacuum is maintained long term, with no observed degradation in cavity stability for over 1 year after bonding. For a 1550 nm laser stabilized to a 9.7 mL in-vacuum bonded cavity, the measured Allan deviation is 2.4 × 10−14 at 1 s and its phase noise is thermal-noise-limited from 0.1 Hz to 10 kHz, reaching about -105 dBc/Hz at 10 kHz offset frequency. This represents the highest stability of any oscillator operated without a vacuum enclosure. Furthermore, we demonstrate a 0.5 mL in-vacuum bonded cavity created using microfabricated mirrors and cavity dicing, with phase noise reaching -95 dBc/Hz at 10 kHz offset frequency. By relieving the need for high-vacuum enclosures, we greatly enhance the portability and utility of low noise, compact cavity-stabilized lasers, with applications ranging from environmental sensing to mobile optical clocks to ultralow noise microwave generation. © 2024, CC BY.

关键词： Cavity resonators

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Quantum permutation puzzles with indistinguishable particles

arXiv

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arXiv 2024年

作者： Lordi, Noah Trank-Greene, Maedée Kyle, Akira Combes, Joshua Department of Physics University of Colorado Boulder 2000 Colorado Ave BoulderCO80309 United States Department of Applied Mathematics University of Colorado Boulder BoulderCO80309 United States Electrical Computer and Energy Engineering University of Colorado Boulder BoulderCO80309 United States Schools of Physics and Mathematics University of Melbourne VIC3010 Australia

Permutation puzzles, such as the Rubik’s cube and the 15 puzzle, are enjoyed by the general public and mathematicians alike. Here we introduce quantum versions of permutation puzzles where the pieces of the puzzles are replaced with indistinguishable quantum particles. The moves in the puzzle are achieved by swapping or permuting the particles. We show that simply permuting the particles can be mapped to a classical permutation puzzle, even though the identical particles are entangled. However, we obtain a genuine quantum puzzle by adding a quantum move—the square root of SWAP. The resulting puzzle cannot be mapped to a classical permutation puzzle. We focus predominately on the quantization of the 2 × 2 slide puzzle and briefly treat the 2 × 2 × 1 Rubik’s cube. © 2024, CC BY.

关键词： Quantum entanglement

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AI-Enabled Jammer Deception Using Decoy Packets

AI-Enabled Jammer Deception Using Decoy Packets

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GLOBECOM 2022 - 2022 IEEE Global Communications Conference

作者： Stephan Frisbie Mohamed Younis The Johns Hopkins University Applied Physics Laboratory Laurel Maryland Department of Computer Science and Electrical Engineering University of Maryland Baltimore County Baltimore Maryland United States

ISBN: (纸本)9781665435413

In this work, we present a learning algorithm for a wireless communications network to transmit decoy packets to counter an adversarial sensing-reactive jammer. As the jammer is required to search across channels for data transmissions, decoy packets can have the effect of stalling the jammer on a particular channel, preventing it from continuing its search and leaving legitimate packets unimpeded. A reinforcement learning algorithm trains a deep neural network with an exploration-exploitation algorithm and experience replay. The state- and action-space and reward function are presented as components of the reinforcement learning framework. Our algorithm is tested with software simulations, modeling ZigBee communications nodes using time-division multiple access for medium access control. A reactive jammer is modeled in the simulation, with the goal of disrupting any detected ZigBee transmissions. A means to measure and distribute the reward function and system state to enable edge-learning in this context is presented as part of the implementation. The results demonstrate the effectiveness of our algorithm in mitigating the jamming attack, outperforming a random decoy strategy by a factor of two.

关键词： Wireless communication Wireless sensor networks Software algorithms Zigbee Reinforcement learning Throughput Software

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Terahertz Landau Polaritons in Nano-slots: Ultrastrong Coupling under Extreme Spatial Confinement

Terahertz Landau Polaritons in Nano-slots: Ultrastrong Coupl...

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International Conference on Infrared and Millimeter Waves

作者： Dasom Kim Sunghwan Kim Dukhyung Lee Shuang Liang Fuyang Tay Michael J. Manfra Dai-Sik Kim Junichiro Kono Department of Electrical and Computer Engineering Rice University Houston TX USA Applied Physics Graduate Program Smalley-Curl Institute Rice University Houston TX USA Department of Physics Long-wavelength Nanotechnology Laboratory and Quantum Photonics Institute Ulsan National Institute of Science and Technology (UNIST) Ulsan South Korea Department of Physics and Astronomy Purdue University West Lafayette IN USA Birck Nanotechnology Center Purdue University West Lafayette IN USA Elmore Family School of Electrical and Computer Engineering Purdue University West Lafayette IN USA School of Materials Engineering Purdue University West Lafayette IN USA Department of Physics and Astronomy Rice University Houston TX USA Department of Material Science and NanoEngineering Rice University Houston TX USA

We report ultrastrong coupling of the cyclotron resonance of a two-dimensional electron gas in a GaAs quantum well to terahertz cavity photons under extreme confinement to the nanometer scale. This was realized by an array of nano-slots fabricated close to the quantum well layer on the GaAs substrate. Our terahertz magnetospectroscopic measurements revealed two polariton branches as a function of applied magnetic field. While the photon-like part of the two polariton branches was clearly observed, the matter-like part was generally elusive. Our electromagnetic simulations quantitatively reproduce our observation for the upper-polariton branch. However, for the lower-polariton branch, our simulations predict a pronounced resonance, which was absent in experimental spectra. This discrepancy may be a consequence of the breakdown of the dipole approximation in this extreme confinement situation.

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