Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 2403.13028

Dynamical systems analysis of a cosmological model with interacting Umami Chaplygin fluid in adiabatic particle creation mechanism: Some bouncing features

Goutam Mandal·Sujay Kr. Biswas
View original source ↗Read source document ↗Export metadata ↓

Abstract

The present work aims to investigate an interacting Umami Chaplygin gas in the background dynamics of a spatially flat Friedmann-Lemaitre-Robertson-Walker (FLRW) universe when adiabatic particle creation is allowed. Here, the universe is taken to be an open thermodynamical model where the particle is created irreversibly and consequently, the creation pressure comes into the energy-momentum tensor of the material content. The particle creation rate is assumed to have a linear relationship with the Hubble parameter ($Γ\propto H$) and the created particle is dark matter (pressureless). With this creation rate a single fluid model studied and found no phase transition. Then, we studied an interacting two-fluid model where second fluid is taken as perfect fluid equation of state and late-time acceleration is obtained. Next, interacting Umami chaplygin gas is studied in context of particle creation. Dynamical stability of the model is performed. Classical stability of the model is also studied at each critical point. Some critical points exhibit the accelerated de Sitter expansion of the universe at both the early phase as well as the late phase of evolution which is characterized by completely Umami Chaplygin fluid equation of state. Scaling solutions are also described by some other critical points showing late-time accelerated attractors in phase space satisfying present observational data, and solving the coincidence problem. In a specific region of parameters, a sequence of critical points is achieved exhibiting a unified cosmic evolution of the universe starting from early inflation (source point), which is followed by a decelerated intermediate phase (saddle solution), and finally goes through the late-time dark energy dominated universe (stable point). Finally, non-singular bouncing behavior of the universe is also investigated for this model numerically.

Explore related subjects

gr-qc

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Goutam Mandal, Sujay Kr. Biswas. 2024-12-25. Dynamical systems analysis of a cosmological model with interacting Umami Chaplygin fluid in adiabatic particle creation mechanism: Some bouncing features. https://doi.org/10.1088/1361-6382%2Fad9f17

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Quantum Correlations of Neutrinos in the Kerr-Newman Space-time

Quantum phases establish a connection between gravitation and quantum information, offering a novel avenue for exploring the properties of space-time. In this paper, we investigate the quantum correlations (QCs) of neutrinos in the Kerr--Newman space-time for both zero- and nonzero-angular-momentum propagation. The results show that, for zero-angular-momentum propagation, the oscillation periods of the survival probability and QCs progressively decrease with propagation distance in the inward direction. In the outward direction, increasing $M$ lengthens the oscillation periods of $P_{ν_e\rightarrowν_e}$, entanglement, and the monogamy of nonlocality, whereas increasing the angular momentum $a$ or charge $Q$ shortens them. For nonzero-angular-momentum propagation, the metric parameters also generate local profile modulations through additional two-path interference terms, rather than merely rescaling the oscillation period. Furthermore, we find that, despite differences in their ranges of variation, entanglement and coherence exhibit highly consistent oscillatory behavior in both propagation cases. These findings provide a comprehensive understanding of neutrino-based relativistic quantum information.

gr-qc↗
arXiv2026

Dynamical tidal response of neutron stars: From effective field theory to gravitational waveforms

We investigate the fully relativistic dynamical tidal response of neutron stars up to second order in the frequency. Combining the worldline effective field theory for extended gravitating bodies with perturbation theory of relativistic stellar models, we derive the tidal deformation induced by an external time-dependent field, including a universal logarithmic running term. In the effective theory, we work in dimensional regularization and, through a consistent matching procedure, obtain for the first time the complete leading-order dynamical tidal corrections to both the conservative dynamics and the gravitational-wave signal of compact binaries, including the scheme-dependent finite terms in addition to the running. We show that, in the relativistic regime, dynamical effects cannot be fully captured by mode excitations alone. The magnitude of the additional contribution depends on the stellar compactness, the equation of state, and the running term. Dynamical Love numbers are significantly enhanced with respect to their static counterparts for relatively small compactness. As a result, although they formally enter the gravitational-wave phase at eighth post-Newtonian order, dynamical tidal effects yield a nonnegligible contribution during the late inspiral. Using a Fisher-matrix analysis, we show that third-generation detectors such as the Einstein Telescope could measure dynamical Love numbers for a range of neutron-star masses and equations of state. Conversely, neglecting these effects can lead to significant biases in the inference of static Love numbers, and hence on the nuclear equation of state. Our results highlight the importance of dynamical tidal effects for high-precision gravitational-wave modeling with future detectors.

gr-qc↗
arXiv2026

Probing quantum chaos near a wormhole throat with a circular string

We investigate whether quantum fluctuations of a circular probe string develop a quantum-chaotic response while traversing a wormhole throat. The classical circular-string embedding is periodic and radially stable, but its two physical transverse polarizations experience time-dependent tidal potentials. Expanding the world-sheet action to quadratic order, we canonically quantize these modes and construct out-of-time-ordered correlator(OTOC) amplitudes from their unequal-time commutators. For the Ellis--Bronnikov wormhole, both polarizations exhibit finite intervals of approximately exponential OTOC growth associated with the first throat passage. The corresponding dimensionless rate measured with respect to physical time is positive over the parameter range studied and generally decreases as the probe energy is increased relative to the throat scale. In the global-monopole extension, increasing the solid-angle deficit narrows the band of locally amplifiable modes and suppresses the extracted rates; a sufficiently strong defect can nearly quench the radial signal, while the angular channel retains a polarization-dependent non-monotonic structure when the energy-to-throat-scale ratio is small. These quantities characterize finite-time dynamical sensitivity in the Gaussian fluctuation sector and should not be identified with asymptotic many-body chaos or a thermodynamic phase transition. Although the numerical analysis uses two representative wormhole geometries, the construction depends only on covariant world-sheet fluctuations and real-time commutators. It therefore provides a transferable, non-holographic framework for applying quantum-chaos diagnostics directly to quantum probes in curved spacetimes.

gr-qc↗