arXiv subjects

Vladan Pankovic

Publications and source records attributed to Vladan Pankovic.

52 records · Page 3Linked to original sources

arXiv2008

A Simple Determination of the Thermodynamical Characteristics of a Very Thin Black Ring

In this work we suggest a very simple, approximate formalism for description of some basic (especially thermodynamical) characteristics of a rotating, very thin black ring. (In fact, our formalism is not theoretically dubious, since, at it is not hard to see, it can correspond to an extreme simplification of a more accurate, Copeland-Lahiri string formalism for the black hole description.) Even if suggested formalism is, generally speaking, phenomenological and rough, obtained final results, unexpectedly, are non-trivial. Concretely, given formalism reproduces exactly Bekenstein-Hawking entropy, Bekenstein quantization of the entropy or horizon area and Hawking temperature of a rotating, very thin black ring obtained earlier using more accurate analysis by Reall, Emparan, Elvang, Virmani etc. (Conceptually it is similar to situation in Bohr's atomic model where energy levels are determined practically exactly even if electron motion is described roughly.) Our formalism, according to suggestions in our previous works, is physically based on the assumption that circumference of the horizon tube holds the natural (integer) number of corresponding reduced Compton's wave length. (It is conceptually similar to Bohr's quantization postulate in Bohr's atomic model interpreted by de Broglie relation.) Also, we use, mathematically, practically only simple algebraic equations (by determination of Hawking temperature we use additionally only simple differentiation of Smarr relation).

gr-qc↗

arXiv2008

The Simplest Determination of the Thermodynamical Characteristics of Kerr-Newman Black Hole

In this work, generalizing our previous results, we determine in an original and the simplest way three most important thermodynamical characteristics (Bekenstein-Hawking entropy, Bekenstein quantization of the entropy or (outer) horizon surface area and Hawking temperature) of Kerr-Newman black hole. We start physically by assumption that circumference of Kerr-Newman black hole (outer) horizon holds the natural (integer) number of corresponding reduced Compton's wave length and use mathematically, practically, only simple algebraic equations. (It is conceptually similar to Bohr's quantization postulate in Bohr's atomic model interpreted by de Broglie relation.)

gr-qc↗

arXiv2008

Can Cosmological Constant be a Forbidden Zone (GAP) in Quantum Vacuum

In this work we suggest, without detailed mathematical analysis, a hypothesis on the physical meaning of cosmological constant. It is primarily based on a conceptual analogy with energy characteristics of the crystal lattice structure, i.e. energy zones theory in solid state physics. Namely, according to some theories (holographic principle, emergent gravity etc.) it is supposed that empty space, i.e. quantum vacuum holds a structure like to crystal lattice. It implies a possibility of the existence of totally occupied zones consisting of many levels of the negative energies as well as at least one negative energy forbidden zone, i.e. negative energy gap without any (occupied or empty) level of the negative energy. We suppose that given negative energy forbidden zone in the quantum vacuum represents effectively a positive energy zone without quantum particles that corresponds to cosmological constant. Also we suggest some other (less extravagant) model of the cosmological constant. Here cosmological constant is usually considered as the effect of the quantum vacuum fluctuations where problem of the cut-off can be solved quite simply since here integration over unlimited domain of the quasi-momentums must be changed by integration over one, finite "Brillouin zone".

astro-ph↗

arXiv2008

The Simplest Determination of the Thermodynamical Characteristics of Schwarzschild, Kerr Andreissner-Nordstrom Black Hole

In this work, generalizing our previous results, we determine in an original and the simplest way three most important thermodynamical characteristics (Bekenstein-Hawking entropy, Bekenstein quantization of the entropy or (outer) horizon surface area and Hawking temperature) of Schwarzschild, Kerr and Reissner-Nordstrom black hole. We start physically by assumption that circumference of black hole (outer) horizon holds the natural (integer) number of corresponding reduced Compton's wave length and use mathematically only simple algebraic equations. (It is conceptually similar to Bohr's quantization postulate in Bohr's atomic model interpreted by de Broglie relation.)

gr-qc↗

arXiv2007

A Simple Theoretical Prediction of the Data Corresponding to Observationally Estimated Value of Cosmological Constant

In this work a satisfactory, simple theoretical prediction of the data corresponding to observationally (by fine tuning condition) estimated value of the cosmological constant is given. It is supposed (in conceptually analogy with holographic principle) that cosmological constant, like classical surface tension coefficient by a liquid drop, does not correspond to a volume (bulk) vacuum mass (energy) density distribution but that it corresponds to a surface vacuum mass (energy) density distribution. Then form of given surface mass distribution and fine tuning condition imply observed growing (for $\sim$ 61 magnitude order) of the scale factor (from initial, corresponding to Planck length, to recent, at the beginning of the cosmic acceleration, corresponding to 10 Glyr length).

astro-ph↗

arXiv2007

C^{1/2}P^{1/2}T^{1/2} Symmetry of the Chaotic Inflation Dynamics

In this work is shown that standard dynamical equations of the chaotic inflation for a massive real scalar field hold an especial local gauge symmetry. Given symmetry admits that inflation field mass can be considered as an especial "charge". Also, it is shown that given equations except expected $CPT$ symmetry, hold surprisingly, $C^{1/2}P^{1/2}T^{1/2}$ symmetry too.

gr-qc↗

arXiv2007

Population Dynamics of Children and Adolescents without Problematic Behavior

In this work we suggest a simple mathematical model for the dynamics of the population of children and adolescents without problematic behavior (criminal activities etc.). This model represents a typical population growth equation but with time dependent (linearly decreasing) population growth coefficient. Given equation admits definition of the half-life time of the non-problematic children behavior as well as a criterion for estimation of the social regulation of the children behavior.

q-bio.PE↗

arXiv2007

Spontaneous Breaking of the Quantum Superposition

In this work spontaneous (non-dynamical) breaking (effective hiding) of the unitary quantum mechanical dynamical symmetry (superposition) is considered. It represents an especial but very interesting case of the general formalism of the spontaneous symmetry breaking (effective hiding). Conceptual analogies with spontaneous breaking of the gauge symmetry in Weinberg-Sallam's electro-weak interaction are pointed out. Also, consequences of the spontaneous superposition breaking in the measurement process are discussed. Measurement can be considered as a typical Landau's continuous phase transition with spontaneous superposition breaking (effective hiding) effectively corresponding to collapse. Here critical values of the order parameters are determined by Heisenberg's uncertainty relations.

quant-ph↗

arXiv2006

A Simple Solution of the Lotka-Volterra Equations

In this work we consider a simple, approximate, tending toward exact, solution of the system of two usual Lotka-Volterra differential equations. Given solution is obtained by an iterative method. In any finite approximation order of this solution, exponents of the corresponding Lotka-Volterra variables have simple, time polynomial form. When approximation order tends to infinity obtained approximate solution converges toward exact solution in some finite time interval.

q-bio.QM↗

arXiv2006

A "Quasi-Rapid" Extinction Population Dynamics and Mammoths Overkill

In this work we suggest and consider an original, simple mathematical model of a "quasi-rapid" extinction population dynamics. It describes a decrease and final extinction of the population of one prey species by a "quasi-rapid" interaction with one predator species with increasing population. This "quasi-rapid" interaction means ecologically that prey species behaves practically quite passively (since there is no time for any reaction, i.e. defense), like an appropriate environment, in respect to "quasi-rapid" activity of the predator species that can have different "quasi-rapid" hunting abilities. Mathematically, our model is based on a non-Lotka-Volterraian system of two differential equations of the first order, first of which is linear while second, depending of a parameter that characterizes hunting ability is nonlinear. We compare suggested "quasi-rapid" extinction population dynamics and the global model of the overkill of the prehistoric megafauna (mammoths). We demonstrate that our "quasi-rapid" extinction population dynamics is able to restitute successfully correlations between empirical (archeological) data and overkill theory in North America as well as Australia. For this reason, we conclude that global overkill theory, completely mathematically modelable by "quasi-rapid" extinction population dynamics can consistently explain the Pleistocene extinctions of the megafauna.

q-bio.PE↗

arXiv2006

A Quantum Gate as a Physical Model of an Universal Arithmetical Algorithm without Church's Undecidability and Godel's Incompleteness

In this work we define an universal arithmetical algorithm, by means of the standard quantum mechanical formalism, called universal qm-arithmetical algorithm. By universal qm-arithmetical algorithm any decidable arithmetical formula (operation) can be decided (realized, calculated. Arithmetic defined by universal qm-arithmetical algorithm called qm-arithmetic one-to-one corresponds to decidable part of the usual arithmetic. We prove that in the qm-arithmetic the undecidable arithmetical formulas (operations) cannot exist (cannot be consistently defined). Or, we prove that qm-arithmetic has no undecidable parts. In this way we show that qm-arithmetic, that holds neither Church's undecidability nor Godel's incompleteness, is decidable and complete. Finally, we suggest that problems of the foundation of the arithmetic, can be solved by qm-arithmetic.

quant-ph↗

arXiv2005

$C_{E}PT$ Symmetry of the Simple Ecological Dynamical Equations

It is shown that all simple ecological, i.e. population dynamical equations (unlimited exponential population growth (or decrease) dynamics, logistic or Verhulst equation, usual and generalized Lotka-Volterra equations) hold a symmetry, called $C_{E}PT$ symmetry. Namely, all simple ecological dynamical equations are invariant (symmetric) in respect to successive application of the time reversal transformation - $T$, space coordinates reversal or parity transformation - $P$, and predator-prey reversal transformation - $C_{E}$ that changes preys in the predators or pure (healthy) in the impure (fatal) environment, and vice versa. It is deeply conceptually analogous to remarkable $CPT$ symmetry of the fundamental physical dynamical equations. Further, it is shown that by more accurate, "microscopic" analysis, given $C_{E}PT$ symmetry becomes explicitly broken.

q-bio.PE↗

arXiv2005

Time Reversal of the Increasing Geometrical Progression of the Population of a Simple Biological Specie

In this work we consider time reversal of the increasing geometrical progression of the population of a simple biological species without any enemies (predators) in the appropriate environment with unlimited resources (food, territory, etc.). It is shown that such time reversal corresponds to appearance of the cannibalism, i.e. self-predaciousness or self-damping phenomena which can be described by a type of difference Verhulst equation.

q-bio.PE↗

arXiv2005

A General Relativistic Generalization of Bell Inequality

In this work a general relativistic generalization of Bell inequality is suggested. Namely,it is proved that practically in any general relativistic metric there is a generalization of Bell inequality.It can be satisfied within theories of local (subluminal) hidden variables, but it cannot be satisfied in the general case within standard quantum mechanical formalism or within theories of nonlocal (superluminal) hidden variables. It is shown too that within theories of nonlocal hidden variables but not in the standard quantum mechanical formalism a paradox appears in the situation when one of the correlated subsystems arrives at a Schwarzschild black hole. Namely, there is no way that black hole horizon obstructs superluminal influences between spin of the subsystem without horizon and spin of the subsystem within horizon,or simply speaking,there is none black hole horizon nor "no hair" theorem for subsystems with correlated spins. It implies that standard quantum mechanical formalism yields unique consistent and complete description of the quantum mechanical phenomenons.

quant-ph↗

arXiv2005

There is Neither Classical Bug with a Superluminal Shadow Nor Quantum Absolute Collapse Nor (Subquantum) Superluminal Hidden Variable

In this work we analyse critically Griffiths's example of the classical superluminal motion of a bug shadow. Griffiths considers that this example is conceptually very close to quantum nonlocality or superluminality,i.e. quantum breaking of the famous Bell inequality. Or, generally, he suggests implicitly an absolute asymmetric duality (subluminality vs. superluminality) principle in any fundamental physical theory.It, he hopes, can be used for a natural interpretation of the quantum mechanics too. But we explain that such Griffiths's interpretation retires implicitly but significantly from usual, Copenhagen interpretation of the standard quantum mechanical formalism. Within Copenhagen interpretation basic complementarity principle represents, in fact, a dynamical symmetry principle (including its spontaneous breaking, i.e. effective hiding by measurement). Similarly, in other fundamental physical theories instead of Griffiths's absolute asymmetric duality principle there is a dynamical symmetry (including its spontaneous breaking, i.e. effective hiding in some of these theories) principle. Finally, we show that Griffiths's example of the bug shadow superluminal motion is definitely incorrect (it sharply contradicts the remarkable Roemer's determination of the speed of light by coming late of Jupiter's first moon shadow).

quant-ph↗

arXiv2004

From Quantum To Classical Dynamics: A Landau Continuous Phase Transition With Spontaneous Superposition Breaking

Developing an earlier proposal (Ne'eman, Damnjanovic, etc), we show herein that there is a Landau continuous phase transition from the exact quantum dynamics to the effectively classical one, occurring via spontaneous superposition breaking (effective hiding), as a special case of the corresponding general formalism (Bernstein). Critical values of the order parameters for this transition are determined by Heisenberg's indeterminacy relations, change continuously, and are in excellent agreement with the recent and remarkable experiments with Bose condensation. It is also shown that such a phase transition can sucessfully model self-collapse (self-decoherence), as an effective classical phenomenon, on the measurement device. This then induces a relative collapse (relative decoherence) as an effective quantum phenomenon on the measured quantum object by measurement. We demonstrate this (including the case of Bose-Einstein condensation) in the well-known cases of the Stern-Gerlach spin measurement, Bell's inequality and the recently discussed quantum superposition on a mirror a la Marshall et al. These results provide for a proof that quantum mechanics, in distinction to all absolute collapse and hidden-variable theories, is local and objective. There now appear no insuperable obstacles to solving the open problems in quantum theory of measurement and foundation of quantum mechanics, and strictly within the standard quantum-mechanical formalism. Simply put, quantum mechanics is a field theory over the Hilbert space, the classical mechanics characteristics of which emerge through spontaneous superposition breaking.

quant-ph↗