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I. V. Vancea

Publications and source records attributed to I. V. Vancea.

At least 19 recordsLinked to original sources
arXiv2025

Non-Null Torus Knotted Gravitational Waves from Gravitoelectromagnetism

In this paper, we construct a non-null torus-knotted gravitational monochromatic wave solution of the linearized Einstein equations in vacuum, employing the gravitoelectromagnetic (GEM) framework by analogy with classical electrodynamics. We derive the geometric objects, including the line element, the Riemann tensor, the Ricci tensor, the Ricci scalar, and the geodesic equation for this background. Also, we investigate two properties inherent to this solution due to its GEM origin: the dual GEM potential and GEM helicity.

gr-qc↗
arXiv2024

Fractional Particle with Fractional First Derivatives

In this paper, we introduce a new classical fractional particle model incorporating fractional first derivatives. This model represents a natural extension of the standard classical particle with kinetic energy being quadratic in fractional first derivatives and fractional linear momenta, similarly to classical mechanics. We derive the corresponding equations of motion and explore the symmetries of the model. Also, we present the formulation in terms of fractional potentials. Two important examples are analytically solved: the free particle and the particle subjected to generalized forces characterized by fractional first derivatives.

physics.gen-ph↗
arXiv2022

Fractional Mimetic Dark Matter Model in Fractional Action-like Variational Approach

In this paper, we propose a new model of fractional mimetic dark matter based on the fractional action-like variational approach FALVA implementation of fractionality. The model is non-local at classical level and its equations of motion are highly non-linear. We discuss two particular cases of non-fractional and fractional mimetic dark fields and solve completely the equations of motion of these models. In particular, we obtain the metric of the fractional physical space-time. Also, we obtain the basic geometrical objects in the two cases.

gr-qc↗
arXiv2016

Flat Directions and Leptogenesis in a "New" $μν$SSM

In this paper, we give a brief review of the Minimal Supersymmetric Standard Model (MSSM) and "$μ$ from $ν$" Supersymmetric Standard Model ($μν$SSM). Then we propose a generalization of $μν$SSM in order to explain the recent ATLAS, CMS and LHCb results. This "new" $μν$SSM generalizes the superpotential $W_{suppot}$ of $μν$SSM by including two terms that generate a mixing among leptons, gauginos and higgsinos while keeping the charginos and neutralinos masses unchanged. Also, it is potentially interesting for cosmological applications as it displays flat directions of the superpotential and a viable leptogenesis mechanism.

hep-ph↗
arXiv2013

Plane waves in noncommutative fluids

We study the dynamics of the noncommutative fuid in the Snyder space perturbatively at the first order in powers of the noncommutative parameter. The linearized noncommutative fluid dynamics is described by a system of coupled linear partial differential equations in which the variables are the fluid density and the fluid potentials. We show that these equations admit a set of solutions that are monocromatic plane waves for the fluid density and two of the potentials and a linear function for the third potential. The energy-momentum tensor of the plane waves is calculated.

hep-th↗
arXiv2012

Noncommutative fluid dynamics in the Snyder space-time

In this paper, we construct for the first time the non-commutative fluid with the deformed Poincare invariance. To this end, the realization formalism of the noncommutative spaces is employed and the results are particularized to the Snyder space. The non-commutative fluid generalizes the fluid model in the action functional formulation to the noncommutative space. The fluid equations of motion and the conserved energy-momentum tensor are obtained.

hep-th↗
arXiv2012

Quantum fluids in the Kaehler parametrization

In this paper we address the problem of the quantization of the perfect relativistic fluids formulated in terms of the Kähler parametrization. This fluid model describes a large set of interesting systems such as the power law energy density fluids, Chaplygin gas, etc. In order to maintain the generality of the model, we apply the BRST method in the reduced phase space in which the fluid degrees of freedom are just the fluid potentials and the fluid current is classically resolved in terms of them. We determine the physical states in this setting, the time evolution and the path integral formulation.

hep-th↗
arXiv2011

Nonequilibrium dynamics of strings in time-dependent plane wave backgrounds

We formulate and study the nonequilibrium dynamics of strings near the singularity of the time-dependent plane wave background in the framework of the Nonequilibrium Thermo Field Dynamics (NETFD). In particular, we construct the Hilbert space of the thermal string oscillators at nonequilibrium and generalize the NETFD to describe the coordinates of the center of mass of the thermal string. The equations of motion of the thermal fields and the Hamiltonian are derived. Due to the time-dependence of the oscillator frequencies, a counterterm is present in the Hamiltonian. This counterterm determines the correlation functions in a perturbative fashion. We compute the two point correlation function of the thermal string at zero order in the power expansion.

hep-th↗
arXiv2011

Entropic Law of Force, Emergent Gravity and the Uncertainty Principle

The entropic formulation of the inertia and the gravity relies on quantum, geometrical and informational arguments. The fact that the results are completly classical is missleading. In this paper we argue that the entropic formulation provides new insights into the quantum nature of the inertia and the gravity. We use the entropic postulate to determine the quantum uncertainty in the law of inertia and in the law of gravity in the Newtonian Mechanics, the Special Relativity and in the General Relativity. These results are obtained by considering the most general quantum property of the matter represented by the Uncertainty Principle and by postulating an expression for the uncertainty of the entropy such that: i) it is the simplest quantum generalization of the postulate of the variation of the entropy and ii) it reduces to the variation of the entropy in the absence of the uncertainty.

hep-th↗
arXiv2011

Noncommutative fluid dynamics in the Kähler parametrization

In this paper, we propose a first order action functional for a large class of systems that generalize the relativistic perfect fluids in the Kähler parametrization to noncommutative spacetimes. We calculate the equations of motion for the fluid potentials and the energy-momentum tensor in the first order in the noncommutative parameter. The density current does not receive any noncommutative corrections and it is conserved under the action of the commutative generators $P_μ$ but the energy-momentum tensor is not. Therefore, we determine the set of constraints under which the energy-momentum tensor is divergenceless. Another set of constraints on the fluid potentials is obtained from the requirement of the invariance of the action under the generalization of the volume preserving transformations of the noncommutative spacetime. We show that the proposed action describes noncommutative fluid models by casting the energy-momentum tensor in the familiar fluid form and identifying the corresponding energy and momentum densities. In the commutative limit, they are identical to the corresponding quantities of the relativistic perfect fluids. The energy-momentum tensor contains a dissipative term that is due to the noncommutative spacetime and vanishes in the commutative limit. Finally, we particularize the theory to the case when the complex fluid potentials are characterized by a function $K(z,\bar{z})$ that is a deformation of the complex plane and show that this model has important common features with the commutative fluid such as infinitely many conserved currents and a conserved axial current that in the commutative case is associated to the topologically conserved linking number.

hep-th↗
arXiv2011

Thermal magnetized D-branes on $R^{1,p}\times T^{d-p-1}$ in the generalized Thermo Field Dynamics approach

We construct the D-brane states at finite temperature in thermal equilibrium in the $\mathbb{R}^{1,p}\times{\mathbb{T}}^{d-p-1}$ spacetime in the presence of cold (unthermalized) Kalb-Ramond (KR) and U(1) gauge potential background. To this end, we first generalize the Thermo Field Dynamics (TFD) to wrapped closed strings. This generalization is consistent with the spatial translation invariance on the string world-sheet. Next, we determine the thermal string vacuum and define the entropy operator. From these data we calculate the entropy of the closed string and the free energy. Finally, we define the thermal D-brane states in $\mathbb{R}^{1,p}\times{\mathbb{T}}^{d-p-1}$ in the presence of cold constant KR field and U(1) gauge potential as the boundary states of the thermal closed string and compute their entropy.

hep-th↗
arXiv2008

New Two Dimensional Massless Field Theory from Bagger-Lambert-Gustavsson Model

By compactifying the Bagger-Lambert-Gustavsson model on $\mathbb{R}^{1,1} \times S^1$, we obtain a new two dimensional massless field theory with dynamical fields valued in the Lie 3-algebra $\mathcal{A}$ coupled with an SO(1,1) scalar and vector field which are valued in the set $End(\mathcal{A})$ of the endomorphisms of the Lie 3-algebra. In the limit $g_{BLG} \to \infty$ the theory reduces to a supersymmetric Lie 3-valued generalization of the Green-Schwarz superstring in the light-cone gauge.

hep-th↗
arXiv2007

First Order Semiclassical Thermal String in the AdS Spacetime

We formulate the finite temperature theory for the free thermal excitations of the bosonic string in the anti-de Sitter (AdS) spacetime in the Thermo Field Dynamics (TFD) approach. The spacetime metric is treated exactly while the string and the thermal reservoir are semiclassically quantized at the first order perturbation theory with respect to the dimensionless parameter $ε= \a ' H^{-2}$. In the conformal $D=2+1$ black-hole AdS background the quantization is exact. The method can be extended to the arbitrary AdS spacetime only in the first order perturbation. This approximation is taken in the center of mass reference frame and it is justified by the fact that at the first order the string dynamics is determined only by the interaction between the {\em free} string oscillation modes and the {\em exact} background. The first order thermal string is obtained by thermalization of the $T = 0$ system carried on by the TFD Bogoliubov operator. We determine the free thermal string states and compute the local entropy and free energy in the center of mass reference frame.

hep-th↗
arXiv2005

Thermal String Vacuum in Black-Hole AdS Spacetime

In this letter we propose a new ansatz for the thermal string in the TFD formulation. From it, we derive the thermal vacuum for the closed bosonic string and calculate the thermal partition function in the blackhole $AdS$ background in the first order of the perturbative quantization.

hep-th↗
arXiv2003

D-Branes at Finite Temperature in TFD

We review the construction of the $D$-branes at finite temperature as boundary states in the Fock space of thermal perturbative closed string. This is a talk presented by I. V. V. at Common Trends in Cosmology and Particle Physics June 2003, Balatonfured, Hungary.

hep-th↗