Tootfinder

Suppressing excitations in the nonlinear Landau-Zener model
Sebastian Deffner, Steve Campbell
https://arxiv.org/abs/2506.11759 https://

Suppressing excitations in the nonlinear Landau-Zener model
Many complex quantum systems can be described by effectively nonlinear dynamics. While such dynamics have many appealing characteristics, they also make the analysis significantly more involved. This is due to the fact that only a few analytical treatments exist, and that the language of quantum mechanics is built for linear operators. For instance, the very formulation of the quantum adiabatic theorem requires the underlying dynamics to be linear. In this work we show that in a generalized Lan…

Global Centers and Phase Portraits in Generalized Duffing Oscillators: A Comprehensive Study of the Center-Focus Problem
Gabriel Rond\'on, Nasrin Sadri
https://arxiv.org/abs/2506.07307

Global Centers and Phase Portraits in Generalized Duffing Oscillators: A Comprehensive Study of the Center-Focus Problem
This work presents a comprehensive study of the generalized Duffing oscillator, a fundamental model in nonlinear dynamics described by the system $$ \dot{x} = y, \quad \dot{y} = -αy - εx^m - σx, $$ where $ε\neq 0$ and $m \geq 1$. We focus on the topological classification of phase portraits, the characterization of global centers, and the absence of limit cycles for $α\neq0$. For the linear case ($m = 1$), we establish necessary and sufficient conditions for the origin to be a global cente…

Data-driven balanced truncation for second-order systems with generalized proportional damping
Sean Reiter, Steffen W. R. Werner
https://arxiv.org/abs/2506.10118

Data-driven balanced truncation for second-order systems with generalized proportional damping
Structured reduced-order modeling is a central component in the computer-aided design of control systems in which cheap-to-evaluate low-dimensional models with physically meaningful internal structures are computed. In this work, we develop a new approach for the structured data-driven surrogate modeling of linear dynamical systems described by second-order time derivatives via balanced truncation model-order reduction. The proposed method is a data-driven reformulation of position-velocity bal…

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Scalable Spatiotemporal Modeling for Bicycle Count Prediction
Rishikesh Yadav, Alexandra M. Schmidt, Aurelie Labbe, Pratheepa Jeganathan, Luis F. Miranda-Moreno
https://arxiv.org/abs/2506.07582

Scalable Spatiotemporal Modeling for Bicycle Count Prediction
We propose a novel sparse spatiotemporal dynamic generalized linear model for efficient inference and prediction of bicycle count data. Assuming Poisson distributed counts with spacetime-varying rates, we model the log-rate using spatiotemporal intercepts, dynamic temporal covariates, and site-specific effects additively. Spatiotemporal dependence is modeled using a spacetime-varying intercept that evolves smoothly over time with spatially correlated errors, and coefficients of some temporal co…

Generalized Lotka-Volterra systems with quenched random interactions and saturating functional response
Marco Zenari, Francesco Ferraro, Sandro Azaele, Amos Maritan, Samir Suweis
https://arxiv.org/abs/2506.04056

Generalized Lotka-Volterra systems with quenched random interactions and saturating functional response
The generalized Lotka-Volterra (GLV) equations with quenched random interactions have been extensively used to investigate the stability and dynamics of complex ecosystems. However, the standard linear interaction model suffers from pathological unbounded growth, especially under strong cooperation or heterogeneity. This work addresses that limitation by introducing a Monod-type saturating functional response into the GLV framework. Using Dynamical Mean Field Theory, we derive analytical expres…

Multiple-Nanowire Superconducting Quantum Interference Devices: Critical Currents, Symmetries, and Vorticity Stability Regions
Cliff Sun, Alexey Bezryadin
https://arxiv.org/abs/2505.23095

Multiple-Nanowire Superconducting Quantum Interference Devices: Critical Currents, Symmetries, and Vorticity Stability Regions
An ordinary superconducting quantum interference device (SQUID) contains two weak links connected in parallel. We model a multiple-wire SQUID (MW-SQUID), generalized in two ways. First, the number of weak links, which are provided by parallel superconducting nanowires, is larger than two. Second, the current-phase relationship of each nanowire is assumed linear, which is typical for a homogeneous superconducting thin wire. For such MW-SQUIDs, our model predicts that the critical current ($I_c$)…

Nonequilibrium transport through the Hubbard dimer
Yaroslav Pavlyukh, Riku Tuovinen
https://arxiv.org/abs/2506.02198 https://arxiv.or…

Nonequilibrium transport through the Hubbard dimer
We apply a computationally efficient approach to study the time- and energy-resolved spectral properties of a two-site Hubbard model using the nonequilibrium Green's function formalism. By employing the iterative generalized Kadanoff-Baym ansatz ($i$GKBA) within a time-linear framework, we avoid the computational cost of solving the full two-time Kadanoff-Baym equations. Spectral information is extracted by coupling the system to multiple narrow-band leads, establishing a direct analogy to phot…

A studentized permutation test for the treatment effect in individual participant data meta-analysis
Phuc Thien Tran, Long-Hao Xu, Christian R\"over, Tim Friede
https://arxiv.org/abs/2505.24774

A studentized permutation test for the treatment effect in individual participant data meta-analysis
Meta-analysis is a well-established tool used to combine data from several independent studies, each of which usually compares the effect of an experimental treatment with a control group. While meta-analyses are often performed using aggregated study summaries, they may also be conducted using individual participant data (IPD). Classical meta-analysis models may be generalized to handle continuous IPD by formulating them within a linear mixed model framework. IPD meta-analyses are commonly bas…