Article
Astronomy & Astrophysics
Xin Guo, Kimball A. Milton, Gerard Kennedy, William P. McNulty, Nima Pourtolami, Yang Li
Summary: This study investigates the impact of quantum fluctuations-induced friction on the energy of particles, focusing on the energetics of a particle moving uniformly in vacuum. The quantum frictional power and force on the particle are calculated in the rest frame of blackbody radiation and the particle, demonstrating the equivalence of two approaches. The quantum vacuum frictional force is shown to be a true drag in the nonequilibrium steady state, independent of the particle's polarizability model and polarization state.
Article
Astronomy & Astrophysics
G. Vernardos
Summary: We present a self-consistent and versatile forward modelling software package for time-varying strongly lensed systems. It addresses the missing time dimension in existing approaches and demonstrates the importance of observation cadence and combining information from different wavelengths in correctly measuring time delays.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Physics, Multidisciplinary
L. Galleani, L. Cohen
Summary: This paper investigates the response of a finite string to white noise and obtains the exact time-dependent spectrum. The time-varying spectrum is defined by ensemble averaging the Wigner distribution. The exact solution is obtained by transforming the string's differential equation into the phase space differential equation of time and frequency and solving it directly. The paper also obtains the time-dependent variance of the process at each position and analyzes the limiting cases for small and large times. Additionally, it validates the results obtained by van Lear Jr, Uhlenbeck, and Lyon through a numerical example and plotted results.
Article
Computer Science, Artificial Intelligence
Roy Cerqueti, Raffaele Mattera
Summary: Little attention has been paid to the long memory in clustering time series using different data features. This study measures the long memory using the estimated Hurst exponent and proposes a time-varying Hurst exponent to account for unrealistic constant values. Applying this approach to stock prices demonstrates the importance of long memory in finance.
INTERNATIONAL JOURNAL OF APPROXIMATE REASONING
(2023)
Article
Astronomy & Astrophysics
Iarley P. Lobo, Joao Paulo Morais Graca, Eduardo Folco Capossoli, Henrique Boschi-Filho
Summary: We propose a sequence of steps and a generic transformation for connecting thermodynamic quantities in the bulk and the boundary. This is achieved by constructing a varying-G map and its usefulness is demonstrated through various examples.
Article
Astronomy & Astrophysics
Bing Sun, Jiachen An, Zhoujian Cao
Summary: This paper investigates the effect of gravitational constant variation on the propagation of gravitational waves. By employing two analytical methods, the study finds that variations in the gravitational constant result in amplitude and phase corrections for gravitational waves, and the time variation of the gravitational constant can be constrained through the propagation of gravitational waves.
Article
Physics, Condensed Matter
Tibebe Birhanu, Yigermal Bassie, Yoseph Abebe
Summary: This paper investigates the effects of external parabolic potential, spatially varying temperature, spatially varying trap potential, and time-varying weak signal on the movement of impurities between lattice sites. The temperature and trap potential induce a phase transition from a single well potential to a triple well effective potential. Additionally, the time-varying signal causes the triple well potential to rock, facilitating the impurities in overcoming the potential barrier. Consequently, the characterization of stochastic resonance is examined analytically and numerically.
EUROPEAN PHYSICAL JOURNAL B
(2023)
Article
Multidisciplinary Sciences
Sarfraz Ali, Maryam Saif, Khuram Ali Khan, Nehad Ali Shah, Wajaree Weera
Summary: The holographic dark energy and modified holographic Ricci dark energy models are investigated in the context of Chern-Simons modified gravity theory to analyze the time-dependent gravitational constant G(t) and cosmological constant Lambda(t). The FRW metric is used to examine the physical and kinematical properties of these models, which predict the accelerated expansion phase of the universe. The results show that Lambda(t) increases while G(t) decreases in both cases. Finally, a mathematical estimation is made for the range of G/G, which is similar to the observational data.
Article
Mechanics
G. Kishore, Anupam Kundu
Summary: In this paper, we study the local time of an Ornstein-Uhlenbeck particle using quantum perturbation theory to find eigenvalues and eigenfunctions, compute cumulants, and analyze large deviations and stationary distributions. Our results provide explicit expressions for mean, variance, and covariance of local times with and without absorbing boundaries. We also examine the approach to a stationary state for local time distributions not conditioned on survival.
JOURNAL OF STATISTICAL MECHANICS-THEORY AND EXPERIMENT
(2021)
Article
Mathematics
Guofeng Tang, Guangyan Jia
Summary: The paper establishes the related backward stochastic dynamic equations on time scales, specifically concerning backward difference-integral. It presents a martingale decomposition theorem and proves the existence and uniqueness of solutions for BS backward difference Es. This work unifies and generalizes similar results in backward stochastic difference equations and backward stochastic differential equations.
JOURNAL OF MATHEMATICS
(2022)
Article
Physics, Applied
Norio Inui
Summary: Strong diamagnetic interactions allow carbon materials to levitate in the atmosphere, with factors such as Brownian motion and attractive surface forces affecting stability. The size of the nanomaterial affects stability, with the Casimir interactions potentially disrupting levitation.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Physics, Particles & Fields
N. A. Lemos, D. Mueller, M. J. Reboucas
Summary: This paper discusses the assumption of orientability in spacetime and proposes a method to explore the orientability of spacetime using quantum vacuum electromagnetic fluctuations.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Multidisciplinary Sciences
Lin Cong, Zi Yuan, Zaiqiao Bai, Xinhe Wang, Wei Zhao, Xinyu Gao, Xiaopeng Hu, Peng Liu, Wanlin Guo, Qunqing Li, Shoushan Fan, Kaili Jiang
Summary: The torsion balance, an ancient scientific instrument, remains a very sensitive force sensor today. A torsional balance array on a chip with the highest sensitivity level, utilizing nanomaterials, is capable of measuring femtonewton forces, potentially serving as an ideal platform for exploring fundamental interactions up to zeptonewton accuracy in the future.
Article
Mathematics, Interdisciplinary Applications
Ezzedine Mliki
Summary: In this paper, the long-time behavior of the generalized mixed fractional Brownian motion (gmfBm) after being time-changed by a tempered stable subordinator or a gamma process is investigated. The results show that the time-changed gmfBm exhibits long-range dependence and can be used to model natural phenomena with long-range dependence, even when the underlying process is not itself long-range dependent.
FRACTAL AND FRACTIONAL
(2023)
Article
Astronomy & Astrophysics
Ahmet Mecit Oztas, Emre Dil
Summary: The study explores the entropic force on the holographic Hubble horizon of the universe, leading to entropic force cosmology which attributes the increase of entropy and accelerated expansion to this force as a source of cosmological constant. By investigating density parameters and distance measures, the model is extended to higher dimensional universes to study early period accelerations and density values of universe contents. The model shows a faster acceleration in early periods and larger luminosity distances for higher redshift values, consistent with inflationary paradigm, as well as indicating larger acceleration in higher dimensions for higher redshifts.
PHYSICS OF THE DARK UNIVERSE
(2021)
