Economics from a Physicist's point of view: Stochastic Dynamics of Supply and Demand in a Single Market. Part I

Proceeding from the concept of rational expectations, a new dynamic model of supply and demand in a single market with one supplier, one buyer, and one kind of commodity is developed. Unlike the cob-web dynamic theories with adaptive expectations that are made up of deterministic difference equations, the new model is cast in the form of stochastic differential equations. The stochasticity is due to random disturbances ("input") to endogenous variables. The disturbances are assumed to be stationary to the second order with zero means and given covariance functions. Two particular versions of the model with different endogenous variables are considered. The first version involves supply, demand, and price. In the second version the stock of commodity is added. Covariance functions and variances of the endogenous variables ("output") are obtained in terms of the spectral theory of stochastic stationary processes. The impact of both deterministic parameters of the model and the random input on the stochastic output is analyzed and new conditions of chaotic instability are found. If these conditions are met, the endogenous variables undergo unbounded chaotic oscillations. As a result, the market that would be stable if undisturbed loses stability and collapses. This phenomenon cannot be discovered even in principle in terms of any cobweb deterministic model.Comment: 10 pages, LaTe

Derivation and New Interpretation of the Lorentz Transformations and Einstein's Theorem of Velocity Addition

It is traditionally believed that the Lorentz transformations (LT) and Einstein's theorem of velocity addition (ETVA), underlying special relativity, cannot be obtained from non-relativistic (classical) mechanics. In the present paper it is shown, however, that both the LT and the ETVA are derivable within the framework of classical kinematics if the speeds of material points are bounded above by a certain universal limit $c_+$ which can coincide with the speed of light $c$ in a vacuum.Comment: 8 page

On an Elementary Derivation of the Hamilton-Jacobi Equation from the Second Law of Newton

It is shown that for a relativistic particle moving in an electromagnetic field its equations of motion written in a form of the second law of Newton can be reduced with the help of elementary operations to the Hamilton-Jacobi equation. The derivation is based on a possibility of transforming the equation of motion to a completely antisymmetric form. Moreover, by perturbing the Hamilton-Jacobi equation we obtain the principle of least action.\ The analogous procedure is easily extended to a general relativistic motion of a charged relativistic particle in an electromagnetic field. It sis also shown that the special-relativistic Hamilton-Jacobi equation for a free particle allows one to easily demonstrate the wave-particle duality inherent to this equation and, in addition, to obtain the operators of the four-momentum whose eigenvalues are the classical four-momentumComment: 12 pages,1 figure Abstract is modified, and a few substantial points missed in the first version are adde

Maguejo-Smolin Transformation as a Consequence of a Specific Definition of Mass, Velocity, and the Upper limit on Energy

We consider an alternative approach to non-linear special-relativistic theories. The point of departure is not $\kappa$-deformed algebra (or even group-theoretical considerations) but rather 3 physical postulates defining particle's velocity, mass, and the upper bound on its energy in terms of the respective classical quantities. For a specific definition of particle's velocity we obtain Magueijo-Smolin (MS) version of the double special-relativistic theory. It is shown that this version follows from the $\kappa$-Poincare algebra by the appropriate choice of on the shell mass, such that it is always less or equal Planck's mass. The $\kappa$-deformed Hamiltonian is found which invalidates some arguments about unphysical predictions of the MS transformation.Comment: 12 pages,1 figure, adding some detailed calculation

Generalized (s-Parameterized) Weyl Transformation

A general canonical transformation of mechanical operators of position and momentum is considered. It is shown that it automatically generates a parameter s which leads to a generalized (or s-parameterized) Wigner function. This allows one to derive a generalized (s-parameterized) Moyal brackets for any dimensions. In the classical limit the s-parameterized Wigner averages of the momentum and its square yield the respective classical values. Interestingly enough,in the latter case the classical Hamilton-Jacobi equation emerges as a consequence of such a transition only if there is a non-zero parameter s.Comment: LaTeX (amsmath, amsextra) 16 pages, appendix (fixing LaTex idiosincrasies); fixing some minor typo

On Some Physical Aspects of Planck-Scale Relativity:A Simplified Approach

The kinematics of the two-scale relativity theory (new relativity) is revisited using a simplified approach. This approach allows us not only to derive the dispersion equation introduced earlier by Kowalski-Glikman, but to find an additional dispersion relation, and, even more important, to provide a physical basis for such relations. They are explained by the fact that in the observer invariant two-scale relativity (new relativity) the Planck constant does nor remain constant anymore, but depends on the universal length scale. This leads to the correct relation between energy and frequency at any scale.Comment: 16 pages,1 figure,LaTe

Schroedinger revisited:How the time-dependent wave equation follows from the Hamilton-Jacobi equation

It is shown how using the classical Hamilton-Jacobi equation one can arrive at the time-dependent wave equation. Although the former equation was originally used by E.Schroedinger to get the wave equation, we propose a different approach. In the first place, we do not use the principle of least action and, in addition, we arrive at the time-dependent equation, while Schroedinger (in his first seminal paper) used the least action principle and obtained the stationary wave equation. The proposed approach works for any classical Hamilton-Jacobi equation. In addition, by introducing information loss into the Hamilton-Jacobi equation we derive in an elementary fashion the wave equations (ranging from the Shroedinger to Klein-Gordon, to Dirac equations). We also apply this technique to a relativistic particle in the gravitational field and obtain the respective wave equation. All this supports 't Hooft's proposal about a possibility of arriving at quantum description from a classical continuum in the presence of information loss.Comment: 19 pages; Some corrections to Introduction and Conclusio

One-Dimensional Motion of Bethe-Johnson Gas

A one dimensional motion of the Bethe-Johnson gas is studied in a context of Landau's hydrodynamical model of a nucleus-nucleon collision. The expressions for the entropy change, representing a generalization of the previously known results, are found. It is shown that these expressions strongly depend on an equation of state for the baryonic matter.Comment: 24 pages, 5 figure

Special relativity as classical kinematics of a particle with the upper bound on its speed. Part II. The general Lorentz transforrmation and the generalized velocity composition theorem

The kinematics of a particle with the upper bound on the particle's speed (a modification of classical kinematics where such a restriction is absent) has been developed in [arXiv:1204.5740]. It was based solely on classical mechanics without employing any concepts , associated with the time dilatation or/and length contraction. It yielded the 1-D Lorentz transformation (LT), free of inconsistencies (inherent in the canonical derivation and interpretations of the LT). Here we apply the same approach to derive the LT for the 3-dimensional motion of a particle and the attendant law of velocity composition. As a result, the infinite set of four-parameter transformations is obtained. The requirement of linearity of these transformations selects out of this set the two-parameter subset . The values of the remaining two parameters ,dictated by physics of the motion, is explicitly determined , yielding the canonical form of the 3-dimensional LT. The generalized law of velocity composition and the attendant invariant ( not postulated apriori) of the motion are derived, As in the one-dimensional case, present derivation, as a whole, does not have any need in introducing the concepts of the time dilatation and length contraction, and is based on the classical concepts of time and space.Comment: 10 page

A comment on the paper "Deformed Boost Transformations that saturate at the Planck Scale" by N.B.Bruno,G.Amelino-Camelia, and J.Kowalski-Glikman

An alternative (simplified) derivation of the dispersion relation and the expressions for the momentum-energy 4-vector $p_i,p_0$ given initially in [1] is provided. It has turned out that in a rather "pedestrian" manner one can obtain in one stroke not only the above relations but also the correct dispersion relation in $\omega-k_i$ space, consistent with the value of a velocity of a massless particle. This is achieved by considering the standard Lorentz algebra for $\omega-k_i$-space. A non-uniqueness of the choice of the time-derivative in the presence of the finite length scale is discussed. It is shown that such non-uniqueness does not affect the dispersion relation in $\omega-k_i$-space. albeit results in different dispersion relations in $p-p_0$-space depending on the choice of the definition of the time derivative.Comment: 9 pages, LaTe