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Papers by Romualdo Tabensky

Research paper thumbnail of Cylindrical self-gravitating fluids with pressure equal to energy density

Research paper thumbnail of A Geometrical Approach to Free-Field Quantization*

A geometrical approach to the quantization of free relativistic fields is given. Complex probabil... more A geometrical approach to the quantization of free relativistic fields is given. Complex probability amplitudes are assigned to the solutions of the classical evolution equation. It is assumed that the evolution is strictly classical, according to the scalar unitary representation of the Poincar group in a functional space. The theory is equivalent to canonical quantization. Apresenta -se uma abordagem geometrica da quantizacao de campos relativist icos li vres, onde ampl i tudes complexas de probabi li dade sao at ri buidas as solucoes da equacao classica de campo. Supoe-se que a evolucao seja estri tament classica, sendo dada pela representacao escalar uni taria do grupo de Poincare em um espaco funcional. A teoria e equivalente a quant i zacao canoni ca.

Research paper thumbnail of Kinetic Energy of Laser Accelerated Charged Particles in a Plasma and the Possibility of Pair Production

Laser Interaction and Related Plasma Phenomena, 1977

Research paper thumbnail of Electrodynamics and the electron equation of motion

Research paper thumbnail of Some Exact Solutions in Relativistic Hydrodynamics

Research paper thumbnail of Classical electron mass renormalization

Lettere Al Nuovo Cimento, 1975

Research paper thumbnail of Relativity, Special

digital Encyclopedia of Applied Physics, 2003

Research paper thumbnail of The square root of general relativity

Physics Letters B, 1977

We introduce spin in a natural manner into general relativity by taking the square root, i la Dir... more We introduce spin in a natural manner into general relativity by taking the square root, i la Dirac, of the Hamiltonian constraints of the theory. This approach leads naturally to local supersymmetry and provides additional understanding and attractiveness for supergravity as a physically cogent extension of Einstein's theory. Introducing spin in a natural manner into general relativity has been a long-standing problem. In this note we take the view [1] that the natural way to introduce spin into a physical system is to take the square root, g la Dirac, of the Hamiltonian constraints [2] which generate the spacetime evolution of the system without spin. This procedure leads automatically to the introduction of new dynamical variab!es obeying anticommutation rules, which are associated with spin degrees of freedom. At least two important physical systems may be regarded as examples of this method, namely the Dirac electron and the spinning string, which are respectively the square root of the Klein-Gordon particle and the spinless string [3]. In order for the square-root approach to work it is necessary that the system at hand should possess at least one constraint which is quadratic in the momenta. Generally covariant systems, among them-par excellence-the gravitational field, are in general of this type. Indeed the gravitational field may be regarded as the most complex in a series of dynamical objects* having dimension zero (particle), one (string), two (membrane) and three (gravity). After the square roots are taken the total number of constraints of the theory increases (but also new dy

Research paper thumbnail of The general solution to Einstein-Maxwell equations with plane symmetry

Journal of Mathematical Physics, 1974

Research paper thumbnail of Simplified calculations for radiation reaction forces

Journal of Mathematical Physics, 1975

The Lorentz–Dirac equation of motion for the electron is derived by a new method which makes tedi... more The Lorentz–Dirac equation of motion for the electron is derived by a new method which makes tedious power series expansions unnecessary.

Research paper thumbnail of Exact solutions to Einstein field equations

Journal of Mathematical Physics, 1975

Research paper thumbnail of Unification of gauge and gravitation theories

Journal of Mathematical Physics, 1976

Research paper thumbnail of Hard rods in the presence of a uniform external field

The Journal of Chemical Physics, 1997

We sum the canonical partition function for a system of hard rods in a box of finite length in th... more We sum the canonical partition function for a system of hard rods in a box of finite length in the presence of a linear external potential ͑gravity͒. From the canonical partition function closed expressions for the pressure at the top and bottom walls, and the chemical potential follow. The canonical number density and higher distribution functions are also determined. In particular it is shown that the number densities at the extremes of the box are proportional to the associated pressures at those points even though this is not generally true in the bulk of the system. It also is shown that the system is naturally divided in two wall zones and, if the density is low enough, a central zone as it is the case for the free field system. An expression for the local pressure is also derived and it is found that, in the thermodynamic limit and in a sufficiently weak external potential, an exact local relation between the number density and the pressure profile ͑equation of state͒ exists in the canonical ensemble within the central region. We also compute the grand canonical partition function for the system and generalize some results from other authors.

Research paper thumbnail of Brans-dicke plane symmetric vacuum

International Journal of Theoretical Physics, 1975

The general solution of the mass zero scalar field coupled to the gravitational field with the as... more The general solution of the mass zero scalar field coupled to the gravitational field with the assumption of plane symmetry is exhibited and partially interpreted. Energy transfer from a gravitational wave to test particles is studied invariantly.

Research paper thumbnail of Plane symmetric self-gravitating fluids with pressure equal to energy density

Communications in Mathematical Physics, 1973

Solutions of the Cauchy problem associated with the Einstein field equations which satisfy genera... more Solutions of the Cauchy problem associated with the Einstein field equations which satisfy general initial conditions are obtained under the assumptions that (1) the source of the gravitational field is a perfect fluid with pressure, p, equal to energy density, w, and (2) the space-time admits the three parameter group of motions of the Euclidean plane, that is, the space-time is plane symmetric. The results apply to the situation where the source of the gravitational field is a massless scalar field since such a source has the same stress-energy tensor as an irrotational fluid with p = w. The relation between characteristic coordinates and comoving ones is discussed and used to interpret a number of special solutions. A solution involving a shock wave is discussed.

Research paper thumbnail of Singularities for fluids with p=ω equation of state

Journal of Mathematical Physics, 1975

Research paper thumbnail of Exact solutions to Einstein field equations

Journal of Mathematical Physics, Apr 1, 1975

Research paper thumbnail of Cylindrical self-gravitating fluids with pressure equal to energy density

Research paper thumbnail of A Geometrical Approach to Free-Field Quantization*

A geometrical approach to the quantization of free relativistic fields is given. Complex probabil... more A geometrical approach to the quantization of free relativistic fields is given. Complex probability amplitudes are assigned to the solutions of the classical evolution equation. It is assumed that the evolution is strictly classical, according to the scalar unitary representation of the Poincar group in a functional space. The theory is equivalent to canonical quantization. Apresenta -se uma abordagem geometrica da quantizacao de campos relativist icos li vres, onde ampl i tudes complexas de probabi li dade sao at ri buidas as solucoes da equacao classica de campo. Supoe-se que a evolucao seja estri tament classica, sendo dada pela representacao escalar uni taria do grupo de Poincare em um espaco funcional. A teoria e equivalente a quant i zacao canoni ca.

Research paper thumbnail of Kinetic Energy of Laser Accelerated Charged Particles in a Plasma and the Possibility of Pair Production

Laser Interaction and Related Plasma Phenomena, 1977

Research paper thumbnail of Electrodynamics and the electron equation of motion

Research paper thumbnail of Some Exact Solutions in Relativistic Hydrodynamics

Research paper thumbnail of Classical electron mass renormalization

Lettere Al Nuovo Cimento, 1975

Research paper thumbnail of Relativity, Special

digital Encyclopedia of Applied Physics, 2003

Research paper thumbnail of The square root of general relativity

Physics Letters B, 1977

We introduce spin in a natural manner into general relativity by taking the square root, i la Dir... more We introduce spin in a natural manner into general relativity by taking the square root, i la Dirac, of the Hamiltonian constraints of the theory. This approach leads naturally to local supersymmetry and provides additional understanding and attractiveness for supergravity as a physically cogent extension of Einstein's theory. Introducing spin in a natural manner into general relativity has been a long-standing problem. In this note we take the view [1] that the natural way to introduce spin into a physical system is to take the square root, g la Dirac, of the Hamiltonian constraints [2] which generate the spacetime evolution of the system without spin. This procedure leads automatically to the introduction of new dynamical variab!es obeying anticommutation rules, which are associated with spin degrees of freedom. At least two important physical systems may be regarded as examples of this method, namely the Dirac electron and the spinning string, which are respectively the square root of the Klein-Gordon particle and the spinless string [3]. In order for the square-root approach to work it is necessary that the system at hand should possess at least one constraint which is quadratic in the momenta. Generally covariant systems, among them-par excellence-the gravitational field, are in general of this type. Indeed the gravitational field may be regarded as the most complex in a series of dynamical objects* having dimension zero (particle), one (string), two (membrane) and three (gravity). After the square roots are taken the total number of constraints of the theory increases (but also new dy

Research paper thumbnail of The general solution to Einstein-Maxwell equations with plane symmetry

Journal of Mathematical Physics, 1974

Research paper thumbnail of Simplified calculations for radiation reaction forces

Journal of Mathematical Physics, 1975

The Lorentz–Dirac equation of motion for the electron is derived by a new method which makes tedi... more The Lorentz–Dirac equation of motion for the electron is derived by a new method which makes tedious power series expansions unnecessary.

Research paper thumbnail of Exact solutions to Einstein field equations

Journal of Mathematical Physics, 1975

Research paper thumbnail of Unification of gauge and gravitation theories

Journal of Mathematical Physics, 1976

Research paper thumbnail of Hard rods in the presence of a uniform external field

The Journal of Chemical Physics, 1997

We sum the canonical partition function for a system of hard rods in a box of finite length in th... more We sum the canonical partition function for a system of hard rods in a box of finite length in the presence of a linear external potential ͑gravity͒. From the canonical partition function closed expressions for the pressure at the top and bottom walls, and the chemical potential follow. The canonical number density and higher distribution functions are also determined. In particular it is shown that the number densities at the extremes of the box are proportional to the associated pressures at those points even though this is not generally true in the bulk of the system. It also is shown that the system is naturally divided in two wall zones and, if the density is low enough, a central zone as it is the case for the free field system. An expression for the local pressure is also derived and it is found that, in the thermodynamic limit and in a sufficiently weak external potential, an exact local relation between the number density and the pressure profile ͑equation of state͒ exists in the canonical ensemble within the central region. We also compute the grand canonical partition function for the system and generalize some results from other authors.

Research paper thumbnail of Brans-dicke plane symmetric vacuum

International Journal of Theoretical Physics, 1975

The general solution of the mass zero scalar field coupled to the gravitational field with the as... more The general solution of the mass zero scalar field coupled to the gravitational field with the assumption of plane symmetry is exhibited and partially interpreted. Energy transfer from a gravitational wave to test particles is studied invariantly.

Research paper thumbnail of Plane symmetric self-gravitating fluids with pressure equal to energy density

Communications in Mathematical Physics, 1973

Solutions of the Cauchy problem associated with the Einstein field equations which satisfy genera... more Solutions of the Cauchy problem associated with the Einstein field equations which satisfy general initial conditions are obtained under the assumptions that (1) the source of the gravitational field is a perfect fluid with pressure, p, equal to energy density, w, and (2) the space-time admits the three parameter group of motions of the Euclidean plane, that is, the space-time is plane symmetric. The results apply to the situation where the source of the gravitational field is a massless scalar field since such a source has the same stress-energy tensor as an irrotational fluid with p = w. The relation between characteristic coordinates and comoving ones is discussed and used to interpret a number of special solutions. A solution involving a shock wave is discussed.

Research paper thumbnail of Singularities for fluids with p=ω equation of state

Journal of Mathematical Physics, 1975

Research paper thumbnail of Exact solutions to Einstein field equations

Journal of Mathematical Physics, Apr 1, 1975