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Related papers: Local Spherical Collapsing Box in Athena++: Numeri…

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We analyze the complexity of classically simulating continuous-time dynamics of locally interacting quantum spin systems with a constant rate of entanglement breaking noise. We prove that a polynomial time classical algorithm can be used to…

Quantum Physics · Physics 2022-11-11 Rahul Trivedi , J. Ignacio Cirac

We describe the implementation of multigrid solvers in the Athena++ adaptive mesh refinement (AMR) framework and their application to the solution of the Poisson equation for self-gravity. The new solvers are built on top of the AMR…

Instrumentation and Methods for Astrophysics · Physics 2023-05-03 Kengo Tomida , James M. Stone

In this paper, we discuss gravitational collapse of spherically symmetric spacetimes. We derive a general formalism by taking two arbitrary spherically symmetric spacetimes with $g_{00}=1$. Israel's junction conditions are used to develop…

General Relativity and Quantum Cosmology · Physics 2009-07-22 M. Sharif , Khadija Iqbal

We present the exact solutions for the collapse of a spherically-symmetric, cold (i.e., pressureless) cloud under its own self-gravity, valid for arbitrary initial density profiles and not restricted to the realm of self-similarity. These…

Astrophysics of Galaxies · Physics 2018-01-08 Eric R. Coughlin

The influence of continuous measurements of energy with a finite accuracy is studied in various quantum systems through a restriction of the Feynman path-integrals around the measurement result. The method, which is equivalent to consider…

Condensed Matter · Physics 2009-10-22 Ubaldo Tambini , Roberto Onofrio , Carlo Presilla

(Abridged) We present local 2D and 3D hybrid numerical simulations of particles and gas in the midplane of protoplanetary disks (PPDs) using the Athena code. The particles are coupled to gas aerodynamically, with particle-to-gas feedback…

Earth and Planetary Astrophysics · Physics 2015-05-19 Xue-Ning Bai , James M. Stone

A method for following fragmentation simulations further in time using smoothed particle hydrodynamics (SPH) is presented. In a normal SPH simulation of the collapse and fragmentation of a molecular cloud, high-density regions of gas that…

Astrophysics · Physics 2015-06-24 M. R. Bate , I. A. Bonnell , N. M. Price

The hydrodynamic vortex, an effective spacetime geometry for propagating sound waves, is studied analytically. In contrast with the familiar Kerr black-hole spacetime, the hydrodynamic vortex model is described by an effective acoustic…

General Relativity and Quantum Cosmology · Physics 2015-06-19 Shahar Hod

This study evaluates colorectal risk factors and compares classical models against Quantum Neural Networks (QNNs) for anastomotic leak prediction. Analyzing clinical data with 14\% leak prevalence, we tested ZZFeatureMap encodings with…

Machine Learning · Computer Science 2026-04-16 Vojtěch Novák , Ivan Zelinka , Lenka Přibylová , Lubomír Martínek , Vladimír Benčurík , Martin Beseda

This article presents an original methodology for the prediction of steady turbulent aerodynamic fields. Due to the important computational cost of high-fidelity aerodynamic simulations, a surrogate model is employed to cope with the…

Fluid Dynamics · Physics 2019-12-05 Romain Dupuis , Jean-Christophe Jouhaud , Pierre Sagaut

This manuscript is devoted to study the combined effect of a viable model, f(R) = R + \alpha R^n, and electromagnetic field on the instability range of gravitational collapse. We assume charged anisotropic fluid that dissipate energy via…

General Relativity and Quantum Cosmology · Physics 2014-02-03 H. Rizwana Kausar , Ifra Noureen

The Gravitational Poissonian Spontaneous Localization (GPSL) model is a hybrid classical-quantum framework in which Newtonian gravity emerges from stochastic collapses of a smeared mass-density operator. Consistency of the hybrid dynamics…

Quantum Physics · Physics 2026-02-24 Nicolò Piccione

Global non-hydrostatic atmospheric models are becoming increasingly important for studying the climates of planets and exoplanets. However, such models suffer from computational difficulties due to the large aspect ratio between the…

Earth and Planetary Astrophysics · Physics 2020-08-12 Huazhi Ge , Cheng Li , Xi Zhang , Dongwook Lee

A time-fractional Allen-Cahn equation with volume constraint is first proposed by introducing a nonlocal time-dependent Lagrange multiplier. Adaptive linear second-order energy stable schemes are developed for the proposed model by…

Numerical Analysis · Mathematics 2020-12-23 Bingquan Ji , Hong-lin Liao , Yuezheng Gong , Luming Zhang

The present work introduces a simple, yet effective particle coalescing procedure for two-dimensional SPH simulations with spatially varying resolution. In addition to the regular conservation properties of former algorithms concerning the…

Computational Physics · Physics 2019-09-24 Balázs Havasi-Tóth

This paper examines the temporal evolution of a two-stage stochastic model for spherical random fields. The model uses a time-fractional stochastic hyperbolic diffusion equation, which describes the evolution of spherical random fields on…

Spectral Theory · Mathematics 2024-12-10 Tareq Alodat , Quoc T. Le Gia

The efficient simulation of quantum dynamics and ground states is a central challenge in physics and a key frontier for quantum advantage. While short-time evolution in one-dimensional systems can often be simulated classically, extending…

Quantum Physics · Physics 2025-09-22 Yusen Wu , Yukun Zhang , Chuan Wang , Xiao Yuan

This paper describes the first steps of development of a new multidimensional time implicit code devoted to the study of hydrodynamical processes in stellar interiors. The code solves the hydrodynamical equations in spherical geometry and…

Instrumentation and Methods for Astrophysics · Physics 2015-05-27 M. Viallet , I. Baraffe , R. Walder

We have developed and implemented an implicit electrolyte model in the Vienna Ab initio Simulation Package (VASP) that includes nonlinear dielectric and ionic responses as well as a nonlocal definition of the cavities defining the spatial…

Chemical Physics · Physics 2023-09-15 S M Rezwanul Islam , Foroogh Khezeli , Stefan Ringe , Craig Plaisance

We study the directional-ordering transition in the two-dimensional classical and quantum compass models on the square lattice by means of Monte Carlo simulations. An improved algorithm is presented which builds on the Wolff cluster…

Statistical Mechanics · Physics 2010-06-23 Sandro Wenzel , Wolfhard Janke , Andreas M. Laeuchli