198 research outputs found
Transverse expansion of hot magnetized Bjorken flow in heavy ion collisions
We argue that the existence of an inhomogeneous external magnetic field can
lead to radial flow in transverse plane. Our aim is to show how the
introduction of a magnetic field generalizes the Bjorken flow. We investigate
the effect of an inhomogeneous weak external magnetic field on the transverse
expansion of in-viscid fluid created in high energy nuclear collisions. In
order to simplify our calculation and compare with Gubser model, we consider
the fluid under investigation to be produced in central collisions, at small
impact parameter; azimuthal symmetry has been considered. In our model, we
assume an inhomogeneous external magnetic field following the power-law decay
in proper time and having radial inhomogeneity perpendicular to the radial
velocity of the in-viscid fluid in the transverse plane; then the space time
evolution of the transverse expansion of the fluid is obtained. We also show
how the existence of an inhomogeneous external magnetic field modifies the
energy density. Finally we use the solutions for the transverse velocity and
energy density in the presence of a weak magnetic field, to estimate the
transverse momentum spectrum of protons and pions emerging from the
Magneto-hydrodynamic solutions
Non-relativistic approximate numerical ideal-magneto hydrodynamics of (1+1) D transverse flow in Bjorken scenario
In this study, we investigate the impact of the magnetic field on the
evolution of the transverse flow of QGP matter in the magneto-hydrodynamic
(MHD) framework. We assume that the magnetic field is perpendicular to the
reaction plane and then we solve the coupled Maxwell and conservation equations
in (1+1D) transverse flow, within the Bjorken scenario. We consider a QGP with
infinite electrical conductivity. First, the magnetic effects on the QGP medium
at mid-rapidity are investigated at leading order; then the time and space
dependence of the energy density, velocity and magnetic field in the transverse
plane of the ideal magnetized hot plasma are obtained
Thermodynamics, phase transitions and Ruppeiner geometry for Einstein-dilaton Lifshitz black holes in the presence of Maxwell and Born-Infeld electrodynamics
In this paper, we first obtain the ()-dimensional dilaton-Lifshitz black
hole (BH) solutions in the presence of Born-Infeld (BI) electrodynamics. We
find that there are two different solutions for and cases
( is dynamical critical exponent). We show that the thermodynamics first law
is satisfied for both cases. Then, we turn to study different phase transitions
(PTs) for our BHs. We start with study of Hawking-Page PT for both linearly and
BI charged BHs. After that, we discuss the PTs inside the BHs. We present the
improved Davies quantities and prove that the PT points shown by them coincide
with Ruppeiner ones. We show that the zero temperature PTs are transitions on
radiance properties of BHs by using Landau-Lifshitz theory. Next, we turn to
study Ruppeiner geometry of linearly and BI charged BHs. For linearly charged
case, we show that there are no PT at finite temperature for the case . For , it is found that the number of finite temperature PT points
depends on the value of BH charge and is not more than two. When we have two
finite temperature PT points, there are no thermally stable BH between these
two points and we have discontinues small/large BH PTs. As expected, for small
BHs, we observe finite magnitude for Ruppeiner invariant which shows the finite
correlation between possible BH molecules while for large BHs, the correlation
is very small. Finally, we study the Ruppeiner geometry and thermal stability
of BI charged Lifshtiz BHs for different values of . We observe that small
BHs are thermally unstable in some situations. Also, the behavior of
correlation between possible BH molecules for large BHs is the same as linearly
charged case. In both linearly and BI charged cases, for some choices of
parameters, the BH systems behave like a Van der Waals gas near transition
point.Comment: V2: 23 pages (revtex format), 13 figures (except one, all include
subfigures), some references adde
Optical properties of Born-Infeld-dilaton-Lifshitz holographic superconductors
In this paper, we first study the Lifshitz-dilaton holographic
superconductors with nonlinear Born-Infeld (BI) gauge field and obtain the
critical temperature of the system for different values of Lifshitz dynamical
exponent, , and nonlinear parameter . We find that for fixed value of
, the critical temperature decreases with increasing . This indicates
that the increase of anisotropy between space and time prevents the phase
transition. Also, for fixed value of , the critical temperature decrease
with increasing . Then, we investigate the optical properties of () and
()-dimensional BI-Lifshitz holographic superconductors in the the presence
of dilaton field. We explore the refractive index of the system. For and
-dimensional holographic superconductor, we observe negative real part
for permittivity as frequency decreases.
Thus, in low frequency region our superconductor exhibit metamaterial property.
This behaviour is independent of the nonlinear parameter and can be seen for
either linear () and nonlinear () electrodynamics. Interestingly,
for ()-dimensional Lifshitz-dilaton holographic superconductors, we
observe metamaterial behavior neither in the presence of linear nor nonlinear
electrodynamics.Comment: 11 pages, 9 figures (including subfigures), some references added in
V
Transverse and non-boost longitudinal expansion of (2+1)dimensional relativistic ideal-hydrodynamics flow in heavy ion collisions
This study investigates the evolution of quark gluon plasma (QGP) within a
generalized Bjorken flow framework. The medium under consideration is assumed
to possess a finite transverse size and to expand both radially and along the
beam axis. However, we assume that the boost invariance of longitudinal
expansion is broken.
To be more specific, we generalize the Bjorken solution to include the
acceleration and transverse expansion of the fluid. We analytically study the
(2 + 1) dimensional longitudinal acceleration expansion of hot and dense quark
matter, applying a perturbation approach to solve the relativistic
hydrodynamics equations. This procedure enables us to obtain exact algebraic
expressions for fluid velocities and energy densities in both transverse and
longitudinal directions.
To simplify our calculations, we assume that the fluid is produced in central
collisions, and therefore, we consider azimuthal symmetry. We compare the
radial velocity and correction energy density with those obtained from the
Gubser model.
Furthermore, we determine the fluid's acceleration parameter and longitudinal
correction energy density, which exhibits a Gaussian distribution
One-dimensional backreacting holographic superconductors with exponential nonlinear electrodynamics
In this paper, we investigate the effects of nonlinear exponential
electrodynamics as well as backreaction on the properties of one-dimensional
-wave holographic superconductors. We continue our study both analytically
and numerically. In analytical study, we employ the Sturm-Liouville method
while in numerical approach we perform the shooting method. We obtain a
relation between the critical temperature and chemical potential analytically.
Our results show a good agreement between analytical and numerical methods. We
observe that the increase in the strength of both nonlinearity and backreaction
parameters causes the formation of condensation in the black hole background
harder and critical temperature lower. These results are consistent with those
obtained for two dimensional -wave holographic superconductors.Comment: 8 pages (two columns), 2 figures (each including 2 subfigures), 3
table
Minority Stress and Leukocyte Gene Expression In Sexual Minority Men Living With Treated HIV Infection
Sexual minority (i.e., non-heterosexual) individuals experience poorer mental and physical health, accounted for in part by the additional burden of sexual minority stress occurring from being situated in a culture favoring heteronormativity. Informed by previous research, the purpose of this study was to identify the relationship between sexual minority stress and leukocyte gene expression related to inflammation, cancer, immune function, and cardiovascular function. Sexual minority men living with HIV who were on anti-retroviral medication, had viral load \u3c 200 copies/mL, and had biologically confirmed, recent methamphetamine use completed minority stress measures and submitted blood samples for RNA sequencing on leukocytes. Differential gene expression and pathway analyses were conducted comparing those with clinically elevated minority stress (n = 18) and those who did not meet the clinical cutoff (n = 20), covarying reactive urine toxicology results for very recent stimulant use. In total, 90 differentially expressed genes and 138 gene set pathways evidencing 2-directional perturbation were observed at false discovery rate (FDR) \u3c 0.10. Of these, 41 of the differentially expressed genes and 35 of the 2-directionally perturbed pathways were identified as functionally related to hypothesized mechanisms of inflammation, cancer, immune function, and cardiovascular function. The neuroactive-ligand receptor pathway (implicated in cancer development) was identified using signaling pathway impact analysis. Our results suggest several potential biological pathways for future work investigating the relationship between sexual minority stress and health
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