Article
Automation & Control Systems
Jennifer Przybilla, Igor Pontes Duff, Peter Benner
Summary: This paper considers the problem of finding surrogate models for large-scale second-order linear time-invariant systems with inhomogeneous initial conditions. Two methodologies are proposed: reducing each component independently and extracting dominant subspaces from Gramians. The error bounds for the overall output approximation are also discussed.
SYSTEMS & CONTROL LETTERS
(2024)
Article
Mathematics, Applied
Matthias Klar, Karsten Matthies, Celia Reina, Johannes Zimmer
Summary: This study explores a class of fast-slow Hamiltonian systems describing the interaction of non-ergodic fast and slow degrees of freedom, focusing on the situation where epsilon is small but positive. It rigorously derives second-order corrections to the homogenised degrees of freedom and analyses the energy of the fast degrees expanded to second-order from a thermodynamic perspective, showing that they satisfy thermodynamic energy relations akin to the laws of thermodynamics. Additionally, a numerical analysis is conducted on the second-order asymptotic expansion of the slow degrees of freedom for a specific system, comparing their approximation quality and total computation time with the original solution.
PHYSICA D-NONLINEAR PHENOMENA
(2021)
Article
Optics
Ling-Feng Zhang, Ling-Zhi Tang, Zhi-Hao Huang, Guo-Qing Zhang, Wei Huang, Dan-Wei Zhang
Summary: This study utilizes machine learning to study the unique topological properties in non-Hermitian systems, training neural networks to predict relevant topological invariants with nearly 100% accuracy. Demonstrations in various models show the capability of neural networks to explore topological invariants and predict them successfully in untouched phase regions.
Article
Physics, Multidisciplinary
Jonas Schwab, Lukas Janssen, Kai Sun, Zi Yang Meng, Igor F. Herbut, Matthias Vojta, Fakher F. Assaad
Summary: We investigate nematic quantum phase transitions in two different Dirac fermion models, finding that both models exhibit continuous phase transitions characterized by large velocity anisotropies in the quantum critical regime.
PHYSICAL REVIEW LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Hong Wu, Bao-Qin Wang, Jun-Hong An
Summary: This study explores the role of periodic driving in creating exotic non-Hermitian SOTIs in 2D and 3D systems, proposing a scheme to retrieve the BBC and provide a complete description of SOTIs through the bulk topology of nonequilibrium systems. It is found that periodic driving can induce rich exotic non-Hermitian SOTIs with tunable numbers of 2D corner states and 3D hinge states, as well as a coexistence of first-and second-order topological insulators.
Article
Automation & Control Systems
Maojiao Ye, Jizhao Yin, Le Yin
Summary: This article investigates the design of distributed Nash equilibrium-seeking strategies for games with second-order integrator-type dynamics. In practical engineering systems, where velocity signals are usually noisy or not accessible for feedback control, this article proposes two estimators to deal with the absence of velocity measurements.
IEEE TRANSACTIONS ON AUTOMATIC CONTROL
(2022)
Article
Materials Science, Multidisciplinary
Dan Guo, Luis M. Moreno-Ramirez, Carlos Romero-Muniz, Yikun Zhang, Jia-Yan Law, Victorino Franco, Jiang Wang, Zhongming Ren
Summary: Rare-earth rich intermetallics crystallizing in an orthorhombic Ho6Co2Ga-type crystal structure exhibit peculiar magnetic properties, with outstanding magnetocaloric effect performance, making them potential for cryogenic magnetic refrigeration applications.
SCIENCE CHINA-MATERIALS
(2021)
Article
Mathematics, Applied
Vladimir Ankudinov, Ilya Starodumov, Peter K. Galenko
Summary: The PFC model is used for modeling crystal micro-structures and dynamics during fast phase transitions, suitable for both first and second order transitions. Specific analytical transformations are used to treat phase transitions of each order, with numerical simulation results showing consistency between atomic distributions and free energies in both forms.
MATHEMATICAL METHODS IN THE APPLIED SCIENCES
(2021)
Article
Physics, Multidisciplinary
Dmitry Solnyshkov, Guillaume Malpuech
Summary: This article discusses the hypothesis of the human brain operating near a critical point and suggests that love may be an example of a second-order phase transition. It analyzes examples from classical literature and common knowledge to support the hypothesis. The author predicts the square root scaling of feelings with time and a critical value of liking for the stability of relationships.
Article
Chemistry, Physical
Sehwan Song, Jiwoong Kim, Jisung Lee, Hyegyeong Kim, Noboru Miyata, Neeraj Kumar, Y. Soh, Jae Hyuck Jang, Chanyong Hwang, Brian J. Kirby, Sungkyun Park
Summary: FeRh thin films exhibit unexpected ferromagnetic characteristics at low temperatures, which is different from their bulk state. The coexistence of antiferromagnetic and residual ferromagnetic states leads to thermomagnetic irreversibility and negative magnetoresistance. Polarized neutron reflectometry reveals the presence of non-uniform ferromagnetic states at the interfaces, with the bottom region correlated to structural distortion and the top region originating from non-stoichiometry.
APPLIED SURFACE SCIENCE
(2023)
Article
Physics, Multidisciplinary
Puspa Upreti, Matthew Krogstad, Charlotte Haley, Mihai Anitescu, Vishwas Rao, Lekh Poudel, Omar Chmaissem, Stephan Rosenkranz, Raymond Osborn
Summary: The paper investigates structural correlations in the quasiskutterudites using single crystal x-ray diffraction and finds temperature-independent local atomic displacements below the transition, which persist to well above the transition, indicating order-disorder behavior.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Fluids & Plasmas
Milan Zukovic, Georgii Kalagov
Summary: We investigate the impact of competing pairwise higher-order interactions (HOI) on the critical behavior of the XY model. Our findings reveal that the critical properties of this generalized model can deviate significantly from the standard XY model, depending on whether the number of HOI terms is odd or even. Odd numbers of HOI terms lead to two consecutive phase transitions, while even numbers of HOI terms only result in two phase transitions under certain conditions.
Article
Mathematics, Applied
Peter Jan van Leeuwen, Michael DeCaria, Nachiketa Chakraborty, Manuel Pulido
Summary: The study introduces a new framework for inferring causal relationships in complex nonlinear systems, which provides complete information theoretic disentanglement and handles nonlinear causal interactions. The framework is built upon information theoretic measures that gradually increase the information available about the target process. Additionally, it can analyze systems that cannot be represented on directed acyclic graphs.
Article
Mathematics
Tamara Kucherenko, Anthony Quas, Christian Wolf
Summary: This paper investigates the regularity of the pressure function of a continuous potential associated with a symbolic dynamical system over a finite alphabet under different temperatures, showing that the existence of a phase transition is indicated by the non-differentiability of the pressure function. By constructing potentials with phase transition properties, it is proven that there may be infinitely many phase transitions within a specific interval.
ADVANCES IN MATHEMATICS
(2021)
Article
Chemistry, Analytical
Fabricio A. Chiappini, Fabiana Gutierrez, Hector C. Goicoechea, Alejandro C. Olivieri
Summary: Multi-way calibration based on second-order data is a groundbreaking advancement in analytical applications. However, most classical chemometric models may not be applicable to data that do not exhibit low rank bilinearity, leading to limitations in achieving the second-order advantage. Different techniques can generate non-bilinear data, which have the potential to be useful for novel second-order calibration methodologies, but comprehensive modeling of non-bilinear second-order data is still underexplored. The analytical performance of three well-known second-order models were evaluated systematically in this research, showing that prediction capacity is significantly influenced by data properties such as instrumental noise level, rank of response matrices, and analyte signal selectivity pattern.
ANALYTICA CHIMICA ACTA
(2021)
Article
Physics, Multidisciplinary
Julien Cornelius, Zhenyu Xu, Avadh Saxena, Aurelia Chenu, Adolfo del Campo
Summary: The study finds that balanced gain and loss in non-Hermitian evolution can enhance the manifestation of quantum chaos and provide a feasible experimental mechanism for spectral filtering.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Jing Yang, Shengshi Pang, Zekai Chen, Andrew N. Jordan, Adolfo del Campo
Summary: A variational principle was developed to optimize the quantum Fisher information for quantum controls and initial state. It was found that for time-independent Hamiltonians with restricted controls, the optimal initial state and controls may depend on probe time. However, the problem can be approximately reduced to the unconstrained case by Floquet engineering, showing that Heisenberg scaling can still be achieved even with limited controls.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Luis Pedro Garcia-Pintos, Schuyler B. Nicholson, Jason R. Green, Adolfo del Campo, Alexey Gorshkov
Summary: The presence of noise or interaction with the environment can significantly impact the dynamics of a isolated quantum system. In this study, we establish a limit on the speed at which observables of open quantum systems can evolve. We consider both the time-energy uncertainty relation and the time-information uncertainty relation, which have been previously derived for classical systems, and extend them to open quantum systems. By separating the coherent and incoherent contributions to system dynamics, we determine lower and upper bounds on the evolution speed. Our findings show that the upper bounds provide tighter limits on the speed of observables compared to known quantum speed limits. Additionally, we identify a preferred basis of speed operators that fully characterizes the observables that reach the speed limits. Furthermore, we use this framework to limit the impact of incoherent dynamics on observable evolution and identify the Hamiltonian that maximizes coherent speedup.
Article
Physics, Multidisciplinary
C. J. O. Reichhardt, A. del Campo, C. Reichhardt
Summary: This study investigates the non-equilibrium phase transitions of superconducting vortices and colloids, and demonstrates that the Kibble-Zurek mechanism is applicable to these transitions. The density of topological defects is measured, and it is found that the defect density scales according to a power law, with exponents falling in the directed percolation universality class. These results suggest that the Kibble-Zurek mechanism can be applied to a broader range of systems exhibiting absorbing phase transitions.
COMMUNICATIONS PHYSICS
(2022)
Article
Physics, Multidisciplinary
Niklas Hornedal, Nicoletta Carabba, Apollonas S. Matsoukas-Roubeas, Adolfo del Campo
Summary: This study introduces a bound on the growth of Krylov complexity in quantum isolated systems by using the uncertainty principle. The authors show the conditions for this bound to be saturated and demonstrate that quantum chaos is not strictly necessary for the saturation of the bound.
COMMUNICATIONS PHYSICS
(2022)
Article
Physics, Multidisciplinary
Jing Yang, Adolfo del Campo
Summary: The exchange operator formalism is used to describe many-body integrable systems in terms of phase-space variables. We establish an equivalence between models described by this formalism and the infinite family of parent Hamiltonians describing quantum many-body models with Jastrow form ground states. This allows us to identify the invariants of motion and establish integrability for any model in the family.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Particles & Fields
Apollonas S. Matsoukas-Roubeas, Federico Roccati, Julien Cornelius, Zhenyu Xu, Aurelia Chenu, Adolfo del Campo
Summary: This research considers a broad class of non-Hermitian Hamiltonian deformations in a nonrelativistic setting, which can describe a large class of open quantum systems, including arbitrary Markovian evolutions conditioned to the absence of quantum jumps. The time evolution operator and time-evolving density matrix in the undeformed and deformed theories are related through integral transforms with a specific kernel. Non-Hermitian Hamiltonian deformations naturally arise in the description of energy diffusion due to time-keeping errors in a real clock used for time evolution tracking. The spectral properties of the dynamical generators associated with the deformed theories are also studied.
JOURNAL OF HIGH ENERGY PHYSICS
(2023)
Article
Quantum Science & Technology
Nicoletta Carabba, Niklas Hornedal, Adolfo del Campo
Summary: This article introduces a generalized quantum speed limit for unitary operator flows, which is used to determine the fundamental time scale of physical processes. The existence of two types of quantum speed limits and their crossover point is demonstrated using a qubit and a random matrix Hamiltonian as examples. The results are further applied to the time evolution of autocorrelation functions, providing computable constraints on the linear dynamical response of out-of-equilibrium quantum systems and the precision of quantum parameter estimation governed by the quantum Fisher information.
Article
Chemistry, Physical
Ali Saffar Shamshirgar, Maria Fernandez Alvarez, Adolfo del Campo, Jose Francisco Fernandez, Rocio E. Rojas Hernandez, Roman Ivanov, Johanna Rosen, Irina Hussainova
Summary: This study incorporates graphene-augmented alumina nanofibers into epoxy resin to fabricate a tunable absorption multilayer structure for electromagnetic interference shielding and RF absorption. Highly aligned graphene augmented alumina nanofibers were produced using a hot wall one-step catalyst-free chemical vapor deposition method. The highest loss tangent of 0.4 was achieved in a composite containing 1 vol% of randomly oriented nanofibers. A superposed three-layer structure was fabricated, offering an absorption of >90% in the entire X-band and an absorption peak of -25 dB at around 11 GHz. The hybrid nanofibers with a dual loss function show potential for versatile design options in RF absorption.
Article
Physics, Multidisciplinary
Hua-Bi Zeng, Chuan-Yin Xia, Adolfo del Campo
Summary: The crossing of a continuous phase transition leads to the formation of topological defects, which is described by the Kibble-Zurek mechanism (KZM) in slow quenches. KZM predicts a universal power-law scaling for the defect density and the quench time. Deviations from KZM in rapid quenches have been experimentally observed and their universality has been established. The defect density and freeze-out time become independent of the quench rate and show a universal power-law scaling with the final value of the control parameter.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Multidisciplinary
Pablo Martinez-Azcona, Aritra Kundu, Adolfo del Campo, Aurelia Chenu
Summary: Noise is prevalent in nature and understanding its impact is crucial. In this study, we introduce a measurable quantity, the stochastic operator variance (SOV), which characterizes the spread of different stochastic trajectories in the space of operators. The dynamics of the SOV is shown to be intimately connected to that of out-of-time-order correlators, defining the quantum Lyapunov exponent. Our findings are validated analytically and numerically in a stochastic Lipkin-Meshkov-Glick Hamiltonian experiencing energy dephasing.
PHYSICAL REVIEW LETTERS
(2023)
Article
Quantum Science & Technology
Kai-Siang Chen, Gelo Noel M. Tabia, Chellasamy Jebarathinam, Shiladitya Mal, Jun-Yi Wu, Yeong-Cherng Liang
Summary: In device-independent quantum information, the correlation between local measurement outcomes observed by separate parties in a Bell test is important, but many questions remain unanswered. The problem of when the boundary of the quantum set coincides with the no-signaling set in the simplest Bell scenario is revisited, and various quantum strategies that realize these correlations are provided. Self-testing is possible in certain classes, and evidence supports the robustness of the results. The set of quantum correlations arising from maximally entangled states is also characterized.
Article
Physics, Multidisciplinary
Tangyou Huang, Yongcheng Ding, Leonce Dupays, Yue Ban, Man Hong-Yung, Adolfo del Campo, Xi Chen
Summary: The simulation of quantum dynamics on a digital quantum computer with parametrized circuits is widely used in fundamental and applied physics and chemistry. The hybrid quantum-classical algorithm, combining classical optimizers and quantum computers, is a competitive strategy for solving specific problems. We propose its use for optimal quantum control. We simulate the wave-packet expansion of a trapped quantum particle on a quantum device with a finite number of qubits, and use circuit learning based on gradient descent to find the connection between control phase transition and quantum speed limit. We discuss the robustness of our method against errors and demonstrate the absence of barren plateaus in the circuit. The combination of digital quantum simulation and hybrid circuit learning opens up new prospects for quantum optimal control.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Optics
Leonce Dupays, Jing Yang, Adolfo del Campo
Summary: In one spatial dimension, the expansion dynamics of a Tonks-Girardeau gas is characterized by dynamical fermionization (DF), which can be controlled and reversed using a generalization of delta-kick cooling (DKC). This provides a simple protocol for rescaling the initial momentum distribution and can be applied to both expansions and compressions, as well as for the microscopy of quantum correlations.
Article
Physics, Multidisciplinary
P. Chandarana, N. N. Hegade, K. Paul, F. Albarran-Arriagada, E. Solano, A. del Campo, Xi Chen
Summary: A digitized version of the QAOA enhanced via the use of counterdiabatic driving term is proposed, demonstrating better performance in Ising models, classical optimization problems, and the P-spin model compared to the standard QAOA.
PHYSICAL REVIEW RESEARCH
(2022)