Article
Thermodynamics
Serdar Ozguc, Liang Pan, Justin A. Weibel
Summary: Efficient thermal management is crucial for electronic devices with nonuniform thermal workloads. A flow-shifting design approach is proposed to fully utilize flow for multiple potential thermal workloads. By optimizing the flow path from each inlet, the flow-shifting heat sink can effectively cool the active heat map.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Physics, Multidisciplinary
Mingu Kang, Shiang Fang, Jeong-Kyu Kim, Brenden R. Ortiz, Sae Hee Ryu, Jimin Kim, Jonggyu Yoo, Giorgio Sangiovanni, Domenico Di Sante, Byeong-Gyu Park, Chris Jozwiak, Aaron Bostwick, Eli Rotenberg, Efthimios Kaxiras, Stephen D. Wilson, Jae-Hoon Park, Riccardo Comin
Summary: This study combines angle-resolved photoemission spectroscopy and density functional theory to reveal the presence of multiple kagome-derived van Hove singularities (vHS) in CsV3Sb5 and their contribution to electronic symmetry breaking. These vHS critically determine the pairing symmetry and unconventional ground states emerging in the AV(3)Sb(5) series.
Article
Mathematics, Applied
Shengtao Zhang, Jiaxi Zhou, Hu Ding, Kai Wang, Daolin Xu
Summary: A new type of nonlinear energy sink (NES) with fractional nonlinearity, called one-third-power (OTP) nonlinearity, is proposed for micro-vibration suppression. The dynamic behaviors of a linear oscillator (LO) with an OTP NES are numerically investigated, and the targeted energy transfer (TET) feature and vibration attenuation performance are evaluated. The results show that the OTP NES has a much lower TET threshold compared to the cubic or third-power (TP) NES. Parametric analysis reveals that a heavier mass or lower stiffness coefficient of the NES promotes TET in the OTP NES system. Furthermore, efficient energy dissipation accompanies significant energy transfer in the OTP NES.
APPLIED MATHEMATICS AND MECHANICS-ENGLISH EDITION
(2023)
Article
Physics, Fluids & Plasmas
Loris Di Cairano, Riccardo Capelli, Ghofrane Bel-Hadj-Aissa, Marco Pettini
Summary: This paper presents a geometrical and thermodynamical analysis of the potential energy landscape of a minimalistic model of a polypeptide. The study reveals that the global geometry and geometric signatures of the equipotential hypersurfaces can discriminate between proteins and random heteropolymers, providing valuable information in understanding the properties of amino acid sequences.
Article
Engineering, Civil
Guo-Xu Wang, Hu Ding
Summary: This paper investigates the optimal mass design of nonlinear energy sinks (NES) using the non-dominated sorting differential evolution algorithm and parameter sensitivity analysis. The study reveals the relationship between optimal mass and vibration mitigation effects under different damping and harmonic excitation strengths. The findings demonstrate the important role of mass design in achieving decent vibration reduction in engineering structures.
ENGINEERING STRUCTURES
(2022)
Article
Materials Science, Multidisciplinary
M. Stalhammar, M. Stone, Masatoshi Sato, T. H. Hansson
Summary: The study reveals that the interface between a topological superconductor and a normal superconductor does not exhibit quantum Hall effect, in contrast to the case of a topological insulator to normal insulator interface. This difference is attributed to the different theoretical models in the coupling of electromagnetic vector potential in the two systems.
Article
Chemistry, Physical
Cheng Zhao, Wei Zhou, Qi Zhou, Zhe Wang, Gaurav Sant, Lijie Guo, Mathieu Bauchy
Summary: The study reveals that Si-rich C-A-S-H gels tend to be homogeneous, while Al-rich C-A-S-H gels tend to phase-separate. This transition is correlated with a topological flexible-to-rigid transition within the atomic network. The propensity for topologically-overconstrained gels to phase-separate arises from internal stress within their atomic network.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2021)
Article
Multidisciplinary Sciences
Stefan Heusler, Paul Schlummer, Malte S. Ubben
Summary: The study proposes a topological model to explain the origin of quantum randomness, elaborates on the mathematical structures behind quantum randomness using group theory and topology, and points out that the 2:1-mapping from SL(2,C) to SO(3,1) plays a crucial role in the observable aspects of quantum physics. Additionally, entanglement leads to a change in topology that makes the distinction between A and B impossible.
Article
Engineering, Mechanical
Bendeguz Dezso Bak, Robert Rochlitz, Tamas Kalmar-Nagy
Summary: We investigated a binary tree-structured multi-degree-of-freedom nonlinear oscillator with impulsive and continuous excitations. The study focused on the response of the system to excitations applied to the largest masses. It was found that the mass of the smallest blocks influenced the system's dissipation and targeted energy transfer efficiency. Use of a simplified frequency energy plot helped analyze the system's response to impulsive excitations, while for continuous excitations, the smallest masses only became active within specific nonlinear frequency bands at high excitation amplitudes.
NONLINEAR DYNAMICS
(2023)
Article
Engineering, Multidisciplinary
Yao XiaoLe, Shi QianLei, Liu Qian, Qin Le, Ju Xing, Xu Chao
Summary: This paper compares the pros and cons of microstructure heat sinks, including microchannel, micro-pin-fin, manifold microchannel, and manifold micro-pin-fin heat sinks. The results show that manifold microchannel and manifold micro-pin-fin heat sinks are superior to microchannel and micro-pin-fin heat sinks. The manifold micro-pin-fin heat sink has lower maximum temperature and thermal resistance, while the manifold microchannel heat sink has lower pressure drop and higher coefficient of performance.
SCIENCE CHINA-TECHNOLOGICAL SCIENCES
(2022)
Article
Chemistry, Physical
Xia Cao, Jiaqing Zhu, Yang Jie, Ping Ma, Zhong Lin Wang
Summary: This paper studied the electromagnetic phenomena generated during collisions, finding that different types of collisions produce varying amounts of electrical energy, which directly affects the law of energy and momentum conservation.
Review
Physics, Multidisciplinary
O. V. Angelsky, I. I. Mokhun, A. Ya. Bekshaev, C. Yu. Zenkova, J. Zheng
Summary: The review discusses the general principles and characteristics of inhomogeneously polarized paraxial optical fields, with a focus on the polarization singularities (PSs). The main parameters of optical vector waves are discussed, along with the physical relevance and topological distinctiveness of the PSs. The review also examines the interrelations between the PSs and phase singularities of scalar fields formed by orthogonal polarization projections, and discusses practical approaches for experimental PS identification and characterization. Additionally, dynamics features of the PSs, such as internal energy flows, optical momentum, and angular momentum distributions, are studied and provide further means for characterization.
FRONTIERS IN PHYSICS
(2023)
Article
Engineering, Mechanical
Sun-Biao Li, Hu Ding
Summary: In this paper, the response characteristics of a dynamic system composed of a nonlinear energy sink (NES) and a linear oscillator under harmonic excitation are analyzed. The necessary conditions for achieving vibration reduction effect with NES are obtained and the minimum frequency and effective damping zone are provided.
NONLINEAR DYNAMICS
(2023)
Article
Mathematics, Applied
Chun-Xiao Nie
Summary: Energy, defined by the eigenvalues of an adjacency matrix, is an important network indicator that incorporates the neighbor information for each node. This article extends the definition of network energy to include higher-order information between nodes, using resistance distances and order complexes. The topological energy (T E), defined by these measures, reveals the characteristics of network structure at multiple scales and can distinguish graphs with the same spectrum.
Article
Acoustics
Guo-Xu Wang, Hu Ding, Li-Qun Chen
Summary: This paper proposes a global control strategy for the primary system and absorber using the differential evolution algorithm, achieving decent vibration mitigation and decreasing the global response.
JOURNAL OF VIBRATION AND CONTROL
(2023)
Article
Physics, Multidisciplinary
Sylvain Lannebere, David E. Fernandes, Tiago A. Morgado, Mario G. Silveirinha
Summary: Inspired by semiconductor transistors, this study introduces a novel class of bulk materials with nonreciprocal and non-Hermitian electromagnetic response. The linearized permittivity tensor lacks Hermitian and transpose symmetries due to material nonlinearities combined with a static electric bias. By using an idealized MOSFET-metamaterial, an electromagnetic isolator is designed that can potentially outperform conventional Faraday isolators due to material gain. It is also suggested that similar material responses can be engineered in natural media in nonequilibrium situations.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Sylvain Lannebere, Mario G. Silveirinha
Summary: This paper proposes a new paradigm for creating superlenses, inspired by the n-p-n junctions of graphene. By connecting an n-type region and a p-type region with a crystal dislocation, it is possible to mimic the interaction of complementary Hamiltonians and achieve subwavelength imaging. The paper introduces an effective model of the system and shows that it predicts perfect lensing for both propagating and evanescent waves.
NEW JOURNAL OF PHYSICS
(2022)
Article
Physics, Nuclear
Iver Brevik, Boris Shapiro, Mario G. Silveirinha
Summary: This paper discusses dispersion forces between neutral material bodies and introduces the concept of Casimir-Lifshitz forces. It also explores a lateral frictional force that occurs when bodies are in relative motion, known as quantum friction. The paper highlights conceptual issues with the theory and points out the problems with the dissipation-less plasma model. Additionally, it presents novel findings on quantum friction, including the possibility of non-stationary friction forces in weakly dissipative systems and an instability phenomenon where kinetic energy is transformed into exponentially growing coherent radiation.
INTERNATIONAL JOURNAL OF MODERN PHYSICS A
(2022)
Article
Physics, Applied
David E. Fernandes, Mario G. Silveirinha
Summary: This study examines the impact of time-reversal symmetry on the dynamic response of nonlinear optical systems that exhibit one-way behavior. It is discovered that nonreciprocal lossless nonlinear materials are typically time-reversal invariant, which raises a paradox since time-reversal invariant systems should be bidirectional. A solution to this conundrum is presented, explaining the compatibility of one-way behavior with time-reversal invariance. It is found that the adiabatic approximation fails to predict the bidirectional nature of nonlinear systems due to the variation in time of incident waves in the time-reversed problem.
PHYSICAL REVIEW APPLIED
(2022)
Article
Physics, Applied
Tiago A. Morgado, Guilherme L. Joao, Ricardo A. M. Pereira, David E. Fernandes, Sylvain Lannebere
Summary: We experimentally prove that a magnetic uniaxial wire medium lens composed of a racemic array of helical-shaped metallic wires can effectively transmit the normal component of the magnetic field of near-field sources with high resolution over a wide frequency range. This helical-shaped wire medium lens can be considered as the magnetic counterpart of traditional wire medium lenses formed by straight metallic wires. The experimental results are further confirmed through full-wave numerical simulations. We anticipate potential applications of this novel metamaterial lens in magnetic resonance imaging, near-field wireless power transfer, and sensing.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Multidisciplinary
Tatiana G. Rappoport, Tiago A. Morgado, Sylvain Lannebere, Mario G. Silveirinha
Summary: The study finds that low-symmetry two-dimensional metallic systems can achieve distributed transistor response and characterizes the optical conductivity. By applying strain to bilayer graphene, optical gain can be realized, leading to a distributed transistor response.
PHYSICAL REVIEW LETTERS
(2023)
Article
Optics
Mario G. Silveirinha
Summary: Topological photonics offers a valuable framework to explain complex wave phenomena in electromagnetic systems. The topological index of a physical system is a global property dependent on the operators describing wave propagation. We establish a significant geometric connection between topological physics and the topological theory of mathematical surfaces. Our findings demonstrate that topological band theory extends the surface topological theory, wherein the surface genus can be considered as a Chern number of a suitable surface operator. We also explore the implications of topology in radiation problems and the bulk-edge correspondence in physical systems.
Article
Nanoscience & Nanotechnology
Filipa R. Prudencio, Mario G. Silveirinha
Summary: In this study, it is demonstrated that isorefractive spacetime crystals with a travelling-wave modulation can rigorously mimic the response of moving material systems. Unlike generic spacetime crystals, which exhibit bi-anisotropic coupling in the co-moving frame, isorefractive crystals show an observer-independent response, resulting in isotropic constitutive relations without any bianisotropy. The researchers show how this property can be utilized in calculating the band diagrams of isorefractive spacetime crystals in the laboratory frame and studying synthetic Fresnel drag. Additionally, the impact of considering either a Galilean or a Lorentz transformation in the homogenization of spacetime crystals is discussed, revealing that the effective response is independent of the transformation considered.
Article
Physics, Applied
Filipa R. Prudencio, Mario G. Silveirinha
Summary: We demonstrate that space-time modulations can be used to achieve complex nonreciprocal couplings, particularly the elusive axion response. We develop an analytical formalism for homogenizing anisotropic space-time crystals in the long wavelength limit and find that space-time crystals with appropriate glide-rotation symmetry can exhibit a giant axion-type response, several orders of magnitude larger than in natural materials. The nonreciprocal axion response has interesting potential applications in optics, such as electromagnetic isolation, and can enable exciting forms of light-wave interactions.
PHYSICAL REVIEW APPLIED
(2023)
Editorial Material
Multidisciplinary Sciences
Mario G. Silveirinha
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)
Article
Optics
Konstantin Y. Bliokh, Ebrahim Karimi, Miles J. Padgett, Miguel A. Alonso, Mark R. Dennis, Angela Dudley, Andrew Forbes, Sina Zahedpour, Scott W. Hancock, Howard M. Milchberg, Stefan Rotter, Franco Nori, Sahin K. Ozdemir, Nicholas Bender, Hui Cao, Paul B. Corkum, Carlos Hernandez-Garcia, Haoran Ren, Yuri Kivshar, Mario G. Silveirinha, Nader Engheta, Arno Rauschenbeutel, Philipp Schneeweiss, Juergen Volz, Daniel Leykam, Daria A. Smirnova, Kexiu Rong, Bo Wang, Erez Hasman, Michela F. Picardi, Anatoly Zayats, Francisco J. Rodriguez-Fortuno, Chenwen Yang, Jie Ren, Alexander B. Khanikaev, Andrea Alu, Etienne Brasselet, Michael Shats, Jo Verbeeck, Peter Schattschneider, Dusan Sarenac, David G. Cory, Dmitry A. Pushin, Michael Birk, Alexey Gorlach, Ido Kaminer, Filippo Cardano, Lorenzo Marrucci, Mario Krenn, Florian Marquardt
Summary: Structured waves are found in all areas of wave physics, both classical and quantum, where the wavefields are inhomogeneous and cannot be approximated by a single plane wave. These complex wavefields with inhomogeneities are crucial in various fields such as nanooptics, photonics, quantum matter waves, acoustics, water waves, etc. This Roadmap surveys the role of structured waves in wave physics, providing background, current research, and anticipating future developments.
Article
Physics, Applied
Antonio Alex-Amor, Carlos Molero, Mario G. Silveirinha
Summary: This paper presents an analytical framework to study scattering and diffraction phenomena in space-time-modulated metallic gratings. By using a Lorentz transformation, it is shown that a specific class of space-time-modulated gratings acts as moving media. The authors take advantage of this property to derive a closed analytical solution for the wave scattering problem, which allows the avoidance of space-time Floquet-Bloch expansions.
PHYSICAL REVIEW APPLIED
(2023)
Article
Materials Science, Multidisciplinary
Joao C. Serra, Mario G. Silveirinha
Summary: We introduce a homogenization approach to characterize the dynamical response of a generic dispersive space-time crystal in the long-wavelength limit. The theory is applied to dispersive space-time platforms with a traveling-wave modulation, and it is shown that for long wavelengths the effective response may be described by a frequency-dependent permittivity. The article discusses the peculiar physics exhibited by dispersive space-time crystals, such as anomalous permittivity dispersion, alternate gain and loss regimes, and multiple resonances in the quasistatic regime.
Article
Materials Science, Multidisciplinary
Joao C. Serra, Mario G. Silveirinha
Summary: Topological photonics is a general framework for designing unidirectional edge waveguides and other platforms with extreme nonreciprocal wave phenomena. This study focuses on the topological classification of photonic crystals formed by inclusions subjected to spacetime rotating-wave modulation. The results show that these crystals have a bianisotropic response that breaks time-reversal symmetry and can lead to nontrivial topologies. A proposal for implementing the Haldane model in a spacetime modulated photonic crystal is also presented.
Article
Materials Science, Multidisciplinary
David E. Fernandes
Summary: In this article, we present an effective medium model for the electron wave propagation in graphene-based nanostructures with imposed electrostatic and magnetic vector potentials. We determine the effective medium parameters using a numerical algorithm and calculate the electronic band structure of the heterostructure. We demonstrate that superlattices with solely a magnetic potential exhibit a reciprocal response characterized by a decrease in charge carrier velocity, while superlattices with both potentials show a nonreciprocal response with a tilted Dirac cone dispersion. We also show the possibility of alternating between different types of Dirac cones by tuning the potentials' amplitudes.
