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Mode-locked laser in nanophotonic lithium niobate

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arXiv 2023年

作者： Guo, Qiushi Sekine, Ryoto Williams, James A. Gutierrez, Benjamin K. Gray, Robert M. Ledezma, Luis Costa, Luis Roy, Arkadev Zhou, Selina Liu, Mingchen Marandi, Alireza Department of Electrical Engineering California Institute of Technology PasadenaCA United States Photonics Initiative Advanced Science Research Center City University of New York NY United States Physics Program Graduate Center City University of New York New YorkNY United States Department of Applied Physics California Institute of Technology PasadenaCA United States Jet Propulsion Laboratory PasadenaCA United States

Mode-locked lasers (MLLs) have enabled ultrafast sciences and technologies by generating ultrashort pulses with peak powers substantially exceeding their average powers. Recently, tremendous efforts have been focused on realizing integrated MLLs not only to address the challenges associated with their size and power demand, but also to enable transforming the ultrafast technologies into nanophotonic chips, and ultimately to unlock their potential for a plethora of applications. However, till now the prospect of integrated MLLs driving ultrafast nanophotonic circuits has remained elusive because of their typically low peak powers, lack of controllability, and challenges with integration with appropriate nanophotonic platforms. Here, we overcome these limitations by demonstrating an electrically-pumped actively MLL in nanophotonic lithium niobate based on its hybrid integration with a III-V semiconductor optical amplifier. Our MLL generates ∼4.8 ps optical pulses around 1065 nm at a repetition rate of ∼10 GHz, with pulse energy exceeding 2.6 pJ and a high peak power beyond 0.5 W. We show that both the repetition rate and the carrier-envelope-offset of the resulting frequency comb can be flexibly controlled in a wide range using the RF driving frequency and the pump current, paving the way for fully-stabilized on-chip frequency combs in nanophotonics. Our work marks an important step toward fully-integrated nonlinear and ultrafast photonic systems in nanophotonic lithium niobate. Copyright © 2023, The Authors. All rights reserved.

关键词： Niobium compounds

Calibration of nuclear charge density distribution by back-propagation neural networks

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arXiv 2022年

作者： Yang, Zu-Xing Fan, Xiao-Hua Naito, Tomoya Niu, Zhong-Ming Li, Zhi-Pan Liang, Haozhao RIKEN Nishina Center Wako351-0198 Japan School of Physical Science and Technology Southwest University Chongqing400715 China RIKEN Interdisciplinary Theoretical and Mathematical Sciences Program Wako351-0198 Japan Department of Physics Graduate School of Science The University of Tokyo Tokyo113-0033 Japan School of Physics and Optoelectronic Engineering Anhui University Hefei230601 China

Based on the back-propagation neural networks and density functional theory, a supervised learning is performed firstly to generate the nuclear charge density distributions. The charge density is further calibrated to the experimental charge radii by a composite loss function. It is found that, when the parity, pairing, and shell effects are taken into account, about 96% of the nuclei in the validation set fall within two standard deviations of the predicted charge radii. The calibrated charge density is then mapped to the matter density, and further mapped to the binding energies according to the Hohenberg-Kohn theorem. It provides an improved description of some nuclei in both binding energies and charge radii. Moreover, the anomalous overbinding in 48Ca implies the existence of an indispensable beyond-mean-field effect. Copyright © 2022, The Authors. All rights reserved.

关键词： Charge density

Interplay and competition between disorder and flat band in an interacting Creutz ladder

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arXiv 2021年

作者： Orito, Takahiro Kuno, Yoshihito Ichinose, Ikuo Quantum Matter Program Graduate School of Advanced Science and Engineering Hiroshima University Higashi-Hiroshima739-8530 Japan Department of Physics Graduate School of Science Tsukuba University Ibaraki Tsukuba305-8571 Japan Department of Applied Physics Nagoya Institute of Technology Nagoya466-8555 Japan

We clarify the interplay and competition between disorder and flat band in the Creutz ladder with inter-particle interactions focusing on the system's dynamics. Without disorder, the Creutz ladder exhibits flat-band many-body localization (FMBL). In this work, we find that disorder generates drastic effects on the system, i.e., addition of it induces a thermal phase first and further increase of it leads the system to the conventional many-body-localized (MBL) phase. The competition gives novel localization properties and unconventional quench dynamics to the system. We first draw the global sketch of the localization phase diagram by focusing on the two-particle system. The thermal phase intrudes between the FMBL and MBL phases, the regime of which depends on the strength of disorder and interactions. Based on the two-particle phase diagram and the properties of the quench dynamics, we further investigate finite-filling cases in detail. At finite-filling fractions, we again find that the interplay/competition between the interactions and disorder in the original flat-band Creutz ladder induces thermal phase, which separate the FMBL and MBL phases. We also verify that the time evolution of the system coincides with the static phase diagrams. For suitable fillings, the conservation of the initial-state information and low-growth entanglement dynamics are also observed. These properties depend on the strength of disorder and interactions. © 2021, CC BY.

关键词： Phase diagrams

Higher-Order Photonic Topological States in Split-Ring Resonators-Based Kagome Lattice

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Higher-Order Photonic Topological States in Split-Ring Reson...

Conference on Lasers and Electro-Optics (CLEO)

作者： D. Zhirihin D. Bobylev D. Tihonenko A. Vakulenko D. Smirnova A. Khanikaev M. Gorlach School of Physics and Engineering ITMO University Saint Petersburg Russia Grove School of Engineering City College of the City University of New York New York NY USA Physics Program Graduate Center of the City University of New York New York NY USA Nonlinear Physics Centre Australian National University Canberra ACT Australia Institute of Applied Physics Russian Academy of Science Nizhny Novgorod Russia

We demonstrate experimentally the emergence of higher-order topological states induced by bianisotropy in a photonic metasurface formed by split-ring resonators (SRR) arranged into a kagome lattice.

ISBN: (数字)9781957171050

ISBN: (纸本)9781665466660

We demonstrate experimentally the emergence of higher-order topological states induced by bianisotropy in a photonic metasurface formed by split-ring resonators (SRR) arranged into a kagome lattice.

关键词： Lattices Metasurfaces Topology Resonators Electrooptical waveguides Photonics

Flat-band full localization and symmetry-protected topological phase on bilayer lattice systems

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arXiv 2021年

作者： Ichinose, Ikuo Orito, Takahiro Kuno, Yoshihito Department of Applied Physics Nagoya Institute of Technology Nagoya466-8555 Japan Quantum Matter program Graduate School of Advanced Science and Engineering Hiroshima University Higashi-Hiroshima739-8530 Japan Department of Physics Graduate School of Science Tsukuba University Ibaraki Tsukuba305-8571 Japan

In this work, we present bilayer flat-band Hamiltonians, in which all bulk states are localized and specified by extensive local integrals of motion (LIOMs). The present systems are bilayer extension of Creutz ladder, which is studied previously. In order to construct models, we employ building blocks, cube operators, which are linear combinations of fermions defined in each cube of the bilayer lattice. There are eight cubic operators, and the Hamiltonians are composed of the number operators of them, the LIOMs. A suitable arrangement of locations of the cube operators is needed to have exact projective Hamiltonians. The projective Hamiltonians belong to a topological classification class, BDI class. With the open boundary condition, the constructed Hamiltonians have gapless edge modes, which commute with each other as well as the Hamiltonian. This result comes from a symmetry analogous to the one-dimensional chiral symmetry of the BDI class. These results indicate that the projective Hamiltonians describe a kind of symmetry protected topological phase matter. Careful investigation of topological indexes, such as Berry phase, string operator, is given. We also show that by using the gapless edge modes, a generalized Sachdev-Ye-Kitaev (SYK) model is constructed. © 2021, CC BY.

关键词： Hamiltonians

Bridging technology and community: Local perceptions of earthquake sensors in Aceh's seismic zones, Indonesia

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International Journal of Disaster Risk Reduction 2025年 126卷

作者： Cut Isna Rina Suryani Oktari Agussabti Agussabti M. Dirhamsyah Muksin Umar Graduate Program in Disaster Science Universitas Syiah Kuala Banda Aceh 23111 Indonesia Tsunami and Disaster Mitigation Research Center (TDMRC) Graduate Program in Disaster Science and Department of Family Medicine Faculty of Medicine Universitas Syiah Kuala Banda Aceh 23111 Indonesia Graduate Program in Disaster Science Department of Agribusiness Faculty of Agriculture and Center for Rural Development & Sustainable Agriculture Studies Universitas Syiah Kuala Banda Aceh 23111 Indonesia Graduate Program in Disaster Science and Department of Mechanical Engineering Faculty of Engineering Universitas Syiah Kuala Banda Aceh 23111 Indonesia Tsunami and Disaster Mitigation Research Center (TDMRC) Graduate Program in Disaster Science and Department of Physics Faculty of Mathematics and Natural Sciences Universitas Syiah Kuala Banda Aceh 23111 Indonesia

The 2004 Aceh tsunami triggered by a major earthquake taught us the importance of disaster mitigation efforts, one of which is monitoring seismic activity using earthquake sensors. However, the success of these sensors is highly dependent on community involvement, awareness, and active maintenance of the technology. This study aims to examine the perceptions of the Acehnese community regarding earthquake sensors and to identify factors that influence their perceptions of this disaster mitigation technology. The study was conducted in six districts in Aceh Province: Aceh Besar, Aceh Selatan, Aceh Singkil, Aceh Utara, Lhokseumawe, and Aceh Tengah, which were selected due to their high seismic activity and the installation of existing earthquake sensors. The study involved 112 respondents who completed a questionnaire to assess their knowledge, perceptions, and attitudes toward sensors. A One Sample T-Test was used to assess each factor influenced perceptions. The study showed that experience was the most influential factor in shaping perceptions, indicating that individuals directly involved in installing the sensors were more likely to appreciate their benefits. This study emphasizes the importance of more targeted educational campaign efforts that emphasize the role and importance of earthquake sensors in reducing earthquake risk and bridging the gap in public understanding of earthquake sensors. By directly involving the community in installing or maintaining earthquake sensors, it can improve their perception and increase the effectiveness of disaster preparedness strategies.

关键词： Community preparedness Disaster education Earthquake mitigation Participatory approach

Noncontextual ontological models of operational probabilistic theories

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arXiv 2025年

作者： Soltani, Sina Erba, Marco Schmid, David Selby, John H. International Centre for Theory of Quantum Technologies Uniwersytet Gdański ul. Jana Bażyńskiego 1A Gdańsk80-309 Poland Perimeter Institute for Theoretical Physics 31 Caroline Street North WaterlooONN2L 2Y5 Canada Theoretical Sciences Visiting Program Okinawa Institute of Science and Technology Graduate University Onna904-0495 Japan

An experiment or theory is classically explainable if it can be reproduced by some noncontextual ontological model. In this work, we adapt the notion of ontological models and generalized noncontextuality so it applies to the framework of operational probabilistic theories (OPTs). A defining feature of quotiented OPTs, which sets them apart from the closely related framework of generalized probabilistic theories (GPTs), is their explicit specification of the structure of instruments, these being generalizations of quantum instruments (including nondestructive measurements);in particular, one needs to explicitly declare which collections of transformations constitute a valid instrument. We are particularly interested in strongly causal OPTs, in which the choice of a future instrument can be conditioned on a past measurement outcome. This instrument structure might seem to permit the possibility of a contextual kind of ontological representation, where the representation of a given transformation depends on which instrument it is considered a part of. However, we prove that this is not possible by showing that for strongly causal quotiented OPTs the structure of instruments does not allow for such a contextual ontological representation. It follows that ontological representations of strongly causal quotiented OPTs are entirely determined by their action on individual transformations, with no dependence on the structure of instruments. Copyright © 2025, The Authors. All rights reserved.

关键词： Quantum theory

A Lattice Boltzmann Method to Quantify the Rare Event Driven Far-Field Impact of Ocean Oil Spills

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SSRN

SSRN 2023年

作者： Zhang, Zhanyang Schäfer, Tobias Kress, Michael E. Computer Science Department College of Staten Island City University of New York 2800 Victory Boulevard Staten IslandNY10314 United States Doctoral Program in Computer Science The Graduate Center City University of New York 365 5th Avenue New YorkNY10016 United States Mathematics Department College of Staten Island City University of New York 2800 Victory Boulevard Staten IslandNY10314 United States Doctoral Program in Physics The Graduate Center City University of New York 365 5th Avenue New YorkNY10016 United States

When oil is released in ocean waters, some regions, e.g. shrimp farms, are susceptible to oil contamination, even at large distances from the spilling source. In this work, we focus on situations where the majority of the oil is expected to not reach these areas. Due to the interplay of advection and diffusion, still small amounts of oil endanger the region. Then, the effect of the pollution is governed by rare events of oil particles reaching the area under consideration posing a modeling *** compare predictions obtained (1) by GNOME (General NOAA Operational Modeling Environment), a tool developed and used by NOAA, and (2) simulation results from our adaptation of the Lattice Boltzmann Method (LBM) focusing on such areas at larger distances from the oil release. We illustrate the performance of both methods by considering a subarea of the Gulf of Mexico and obtaining the surface velocity field from the Unified Wave Interface-Coupled Model (UWIN-CM). Our initial findings are that the Lattice-Boltzmann approach, due to its algorithmic efficiency, shows advantages over GNOME and should be considered as a possible choice when using simulations in order to predict the likelihood of oil reaching regions far from the main oil spill. © 2023, The Authors. All rights reserved.

关键词： Oil spills

Deformed Fredkin model for the ν=5/2 Moore-Read state on thin cylinders

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arXiv 2023年

作者： Voinea, Cristian Pu, Songyang Kirmani, Ammar Ghaemi, Pouyan Rahmani, Armin Papić, Zlatko School of Physics and Astronomy University of Leeds LeedsLS2 9JT United Kingdom Theoretical Division T-4 Los Alamos National Laboratory Los AlamosNM87545 United States Physics Department City College of the City University of New York NY10031 United States Physics Program Graduate Center of City University of New York NY10031 United States Department of Physics and Astronomy Advanced Materials Science and Engineering Center Western Washington University BellinghamWA98225 United States

We propose a frustration-free model for the Moore-Read quantum Hall state on sufficiently thin cylinders with circumferences 7 magnetic lengths. While the Moore-Read Hamiltonian involves complicated long-range interactions between triplets of electrons in a Landau level, our effective model is a simpler one-dimensional chain of qubits with deformed Fredkin gates. We show that the ground state of the Fredkin model has high overlap with the Moore-Read wave function and accurately reproduces the latter’s entanglement properties. Moreover, we demonstrate that the model captures the dynamical response of the Moore-Read state to a geometric quench, induced by suddenly changing the anisotropy of the system. We elucidate the underlying mechanism of the quench dynamics and show that it coincides with the linearized bimetric field theory. The minimal model introduced here can be directly implemented as a first step towards quantum simulation of the Moore-Read state, as we demonstrate by deriving an efficient circuit approximation to the ground state and implementing it on IBM quantum processor. © 2023, CC BY.

关键词： Ground state