Bosonization in curved spacetime maps massive Thirring model (self-interacting Dirac fermions) to a generalized Sine–Gordon model, both living in
1
+
1
-dimensional curved spacetime. Applying this ...duality we have shown that the Thirring model fermion, in non-relativistic limit, gets identified with the soliton of non-linear Scrodinger model with Kerr form of non-linearity. We discuss one particular optical soliton in the latter model and relate it with the Thirring model fermion.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We show that the Equivalence Principle is violated by Quantum Gravity (QG) effects. The predicted violations are compared to experimental observations for Gravitational Redshift, Law of Reciprocal ...Action and Universality of Free Fall. This allows us to derive explicit bounds for β-the QG scale. In our approach, there appears a deviation in the geodesic motion of a particle. This deviation is induced by a non-commutative spacetime, consistent with a Generalized Uncertainty Principle (GUP). GUP admits the presence of a minimum length scale, that is advocated by QG theories. Remarkably, the GUP induced corrections are quite robust since the bound on β obtained by us, in General Relativity scenario in an essentially classical setting of modified geodesic motion, is closely comparable to similar bounds in recent literature (Das and Vagenas 2008 Phys. Rev. Lett. 101 221301). The latter are computed in purely quantum physics domain in flat spacetime.
ABSTRACT
Unified cosmological models have received a lot of attention in astrophysics community for explaining both the dark matter and dark energy evolution. The Chaplygin cosmologies, a well-known ...name in this group have been investigated matched with observations from different sources. Obviously, Chaplygin cosmologies have to obey restrictions in order to be consistent with the observational data. As a consequence, alternative unified models, differing from Chaplygin model, are of special interest. In the present work, we consider a specific example of such a unified cosmological model, that is quantified by only a single parameter μ, that can be considered as a minimal extension of the Λ-cold dark matter cosmology. We investigate its observational boundaries together with an analysis of the universe at large scale. Our study shows that at early time the model behaves like a dust, and as time evolves, it mimics a dark energy fluid depicting a clear transition from the early decelerating phase to the late cosmic accelerating phase. Finally, the model approaches the cosmological constant boundary in an asymptotic manner. We remark that for the present unified model, the estimations of H0 are slightly higher than its local estimation and thus alleviating the H0 tension.
Surface modification techniques have been developed significantly in the last couple of decades for enhanced tribological performance of artificial hip implants. Surface modification techniques ...improve biological, chemical and mechanical properties of implant surfaces. Some of the most effective techniques, namely surface texturing, surface coating, and surface grafting, are applied to reduce the friction and wear of artificial implants. This article reviews the status of the developments of surface modification techniques and their effects on commonly used artificial joint implants. This study focused only on artificial hip joint prostheses research of the last 10 years. A total of 27 articles were critically reviewed and categorized according to surface modification technique. The literature reveals that modified surfaces exhibit reduced friction and enhanced wear resistance of the contact surfaces. However, the wear rates are still noticeable in case of surface texturing and surface coating. The associated vortex flow aids to release entrapped wear debris and thus increase the wear particles generation in case of textured surfaces. The earlier delamination of coating materials due to poor adhesion and graphitization transformation has limited the use of coating techniques. Moreover, the produced wear debris has adverse effects on biological fluid. Conversely, the surface grafting technique provides phospholipid like layer that exhibited lower friction and almost zero wear rates even after a longer period of friction and wear test. The findings suggest that further investigations are required to identify the role of surface grafting on film formation and heat resistance ability under physiological hip joint conditions for improved performance and longevity of hip implants.
The present work discusses motion of neutral and charged particles in Reissner–Nordström spacetime. The constant energy paths are derived in a variational principle framework using the Jacobi metric ...which is parameterized by conserved particle energy. Of particular interest is the case of particle charge and Reissner–Nordström black hole charge being of same sign, since this leads to a clash of opposing forces—gravitational (attractive) and Coulomb (repulsive). Our paper aims to complement the recent work of Pugliese et al. (Eur Phys J C 77:206.
arXiv:1304.2940
,
2017
; Phys Rev D 88:024042.
arXiv:1303.6250
,
2013
). The energy dependent Gaussian curvature (induced by the Jacobi metric) plays an important role in classifying the trajectories.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The paper is devoted to a detailed study of the effects of quantum corrections on the chaotic behaviour in the dynamics of a (massless) probe particle near the horizon of a generalized Schwarzschild ...black hole. Two possible origins inducing the modification of black hole metric are considered separately; the noncommutative geometry inspired metric (suggested by Nicolini, Smailagic and Spallucci) and the metric with quantum field theoretic corrections (derived by Donoghue). Our results clearly show that in both cases, the metric extensions favour chaotic behaviour, namely chaos is attained for relatively lower particle energy. This is demonstrated numerically by exhibiting the breaking of the KAM tori in Poincaré sections of particle trajectories and also via explicit computation of the (positive) Lyapunov exponents of the trajectories.
The Shapere–Wilczek model 1, or so called fgh model, enjoys the remarkable features of a Time Crystal (TC) that has a non-trivial time dependence in its lowest energy state (or the classical ground ...state). We construct a particular form of fgh model (with specified f,g,h functions) that is derived from a Mini-superspace version of a quadratic f(R,Rμν) gravity theory. Main part of the investigation deals with thermodynamic properties of such systems from classical statistical mechanics perspective. Our analysis reveals the possibility of a phase transition. Because of the higher (time) derivative nature of the model computation of the partial function is non-trivial and requires newly discovered techniques. We speculate about possible connection between our model and the Multiverse scenario.
Abstract
Animal behavior involves complex interactions between physiology and psychology. However, most AI systems neglect psychological factors in decision-making due to a limited understanding of ...the physiological-psychological connection at the neuronal level. Recent advancements in brain imaging and genetics have uncovered specific neural circuits that regulate behaviors like feeding. By developing neuro-mimetic circuits that incorporate both physiology and psychology, a new emotional-AI paradigm can be established that bridges the gap between humans and machines. This study presents a bio-inspired gustatory circuit that mimics adaptive feeding behavior in humans, considering both physiological states (hunger) and psychological states (appetite). Graphene-based chemitransistors serve as artificial gustatory taste receptors, forming an electronic tongue, while 1L-MoS
2
memtransistors construct an electronic-gustatory-cortex comprising a hunger neuron, appetite neuron, and feeding circuit. This work proposes a novel paradigm for emotional neuromorphic systems with broad implications for human health. The concept of gustatory emotional intelligence can extend to other sensory systems, benefiting future humanoid AI.
•We provide a detailed experimental autoimmune encephalomyelitis (EAE) protocol.•This protocol uses two myelin oligodendrocyte glycoprotein (MOG35-55) injections.•Ascending paralysis is consistently ...observed in 80-100% of MOG35-55 immunized mice.•Robust multiple sclerosis (MS)-like central nervous system pathology is observed.•Providing this protocol facilitates comparability between pre-clinical studies.
While many groups use experimental autoimmune encephalomyelitis (EAE) as a model to uncover therapeutic targets and understand the pathology underlying multiple sclerosis (MS), EAE protocol variability introduces discrepancies in central nervous system (CNS) pathogenesis and clinical disease, limiting the comparability between studies and slowing much-needed translational research.
Here we describe a detailed, reliable protocol for chronic EAE induction in C57BL/6 mice utilizing two injections of myelin oligodendrocyte glycoprotein (35–55) peptide mixed with complete Freund’s adjuvant and paired with pertussis toxin.
The active MOG35-55-EAE protocol presented here induces ascending paralysis in 80–100% of immunized mice. We observe: (1) consistent T cell immune activation, (2) robust CNS infiltration by peripheral immune cells, and (3) perivascular demyelinating lesions concurrent with axon damage in the spinal cord and various brain regions, including the optic nerve, cortex, hippocampus, internal capsule, and cerebellum.
Lack of detailed protocols, combined with variability between laboratories, make EAE results difficult to compare and hinder the use of this model for therapeutic development. We provide the most detailed active MOG35-55-EAE protocol to date. With this protocol, we observe high disease incidence and a consistent, reliable disease course. The resulting pathology is MS-like and includes optic neuritis, perivascular mononuclear infiltration, CNS axon demyelination, and axon damage in both infiltrating lesions and otherwise normal-appearing white matter.
By providing a detailed active MOG35-55-EAE protocol that yields consistent and robust pathology, we aim to foster comparability between pre-clinical studies and facilitate the discovery of MS therapeutics.
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