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Papers by Roberto Sussman Livovsky

Research paper thumbnail of Approaching the Dark Sector through a bounding curvature criterion

Monthly Notices of the Royal Astronomical Society, May 17, 2017

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Research paper thumbnail of Aerial Transmission of the SARS-CoV-2 Virus through Environmental E-Cigarette Aerosols: Implications for Public Policies

International Journal of Environmental Research and Public Health, Feb 3, 2021

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Research paper thumbnail of Spherically symmetric solutions admitting a spacelike self‐similar motion

Journal of Mathematical Physics, 1991

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Research paper thumbnail of Dark energy or apparent acceleration due to a relativistic cosmological model more complex than the Friedmann-Lemaitre-Robertson-Walker model?

Physical review, Dec 29, 2008

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Research paper thumbnail of A novel approach to the dynamics of Szekeres dust models

Classical and Quantum Gravity, Mar 1, 2012

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Research paper thumbnail of Building Non-Spherical Cosmic Structures

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Research paper thumbnail of Averaging and Back–Reaction in Spherically Symmetric Dust Models

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Research paper thumbnail of Gravitational entropy of local cosmic voids

Classical and Quantum Gravity, Jul 28, 2015

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Research paper thumbnail of Invariant characterization of the growing and decaying density modes in LTB dust models

Classical and Quantum Gravity, Oct 8, 2013

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Research paper thumbnail of Review of: "What substances are adolescents vaping? Estimating nicotine-specific and marijuana-specific vaping from US national youth surveys

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Research paper thumbnail of Local dynamics and gravitational collapse of a self-gravitating magnetized Fermi gas

General Relativity and Gravitation, Nov 30, 2007

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Research paper thumbnail of Cosmological backreaction in spherical and plane symmetric dust-filled space-times

Classical and Quantum Gravity, Sep 18, 2019

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Research paper thumbnail of Thermodynamics of the Stephani Universes

Journal of Mathematical Physics, Mar 1, 1995

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Research paper thumbnail of A general relativistic approach to the Navarro–Frenk–White galactic halos

Classical and Quantum Gravity, Oct 30, 2004

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Research paper thumbnail of Evolution of radial profiles in regular Lemaître–Tolman–Bondi dust models

Classical and Quantum Gravity, Jul 16, 2010

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Research paper thumbnail of On spherically symmetric shear‐free perfect fluid configurations (neutral and charged). I

Journal of Mathematical Physics, May 1, 1987

A class of solutions describing a wide variety of nonstatic, spherically symmetric, charged, shea... more A class of solutions describing a wide variety of nonstatic, spherically symmetric, charged, shear-free perfect fluid configurations is derived. It is presented in the form of Jacobian elliptic functions characterized by seven free parameters: five constants and two arbitrary functions of time. This class of solutions is the most general charged version of the class derived by Kustaanheimo and Qvist [Comment. Phys. Math. Helsingf. 13, 12 (1948); Exact Solutions of Einstein’s Field Equations (Cambridge U. P., Cambridge, 1980), Chap. 12, Sec. 2]. It is found that many of the charged particular solutions expressible by elementary functions are new. Particular solutions, including neutral and uniform density solutions, are classified in detail. The physical interpretation of these solutions, including the study of their singularity structure, will be presented in a subsequent paper (Part II).

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Research paper thumbnail of Scalar field “mini-MACHOs”: A new explanation for galactic dark matter

Physical review, Aug 26, 2004

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Research paper thumbnail of Conformal structure of a Schwarzschild black hole immersed in a Friedman universe

General Relativity and Gravitation, Mar 1, 1985

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Research paper thumbnail of Back-reaction and effective acceleration in generic LTB dust models

Classical and Quantum Gravity, Nov 4, 2011

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Research paper thumbnail of On spherically symmetric shear‐free perfect fluid configurations (neutral and charged). II. Equation of state and singularities

Journal of Mathematical Physics, Apr 1, 1988

Geometrical and physical properties of the solutions derived and classified in Part I [J. Math. P... more Geometrical and physical properties of the solutions derived and classified in Part I [J. Math. Phys. 28, 1118 (1987)] are examined in detail. It is shown how the imposition of zero shear restricts the possible choices of equations of state. Two types of singular boundaries arising in these solutions are examined by verifying the local behavior of causal curves approaching these boundaries. For this purpose, a criterion due to C. J. S. Clarke (private communication) is given, allowing one to test the completeness of arbitrary accelerated timelike curves in terms of their acceleration and proper time. One of these boundaries is a spacelike singularity at which causal curves terminate as pressure diverges but matter-energy and charge densities remain finite. At the other boundary, which is timelike if the expansion Θ is finite, proper volume of local fluid elements vanishes as all state variables diverge but causal curves are complete. If Θ diverges at this boundary, a null singularity arises as the end product of the collapse of a two-sphere generated by a given class of timelike curves. The gravitational collapse of bounded spheres matched to a Schwarzschild or Reissner–Nordstro/m exterior is also examined in detail. It is shown that the spacelike singularity mentioned above could be naked under certain parameter choices. Solutions presenting the other boundary produce very peculiar black holes in which the ‘‘surface’’ of the sphere collapses into the above mentioned null singularity, while the ‘‘interior’’ fluid layers avoid this singularity and evolve towards their infinite future.

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Research paper thumbnail of Approaching the Dark Sector through a bounding curvature criterion

Monthly Notices of the Royal Astronomical Society, May 17, 2017

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Research paper thumbnail of Aerial Transmission of the SARS-CoV-2 Virus through Environmental E-Cigarette Aerosols: Implications for Public Policies

International Journal of Environmental Research and Public Health, Feb 3, 2021

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Research paper thumbnail of Spherically symmetric solutions admitting a spacelike self‐similar motion

Journal of Mathematical Physics, 1991

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Research paper thumbnail of Dark energy or apparent acceleration due to a relativistic cosmological model more complex than the Friedmann-Lemaitre-Robertson-Walker model?

Physical review, Dec 29, 2008

Bookmarks Related papers MentionsView impact

Research paper thumbnail of A novel approach to the dynamics of Szekeres dust models

Classical and Quantum Gravity, Mar 1, 2012

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Research paper thumbnail of Building Non-Spherical Cosmic Structures

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Averaging and Back–Reaction in Spherically Symmetric Dust Models

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Gravitational entropy of local cosmic voids

Classical and Quantum Gravity, Jul 28, 2015

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Research paper thumbnail of Invariant characterization of the growing and decaying density modes in LTB dust models

Classical and Quantum Gravity, Oct 8, 2013

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Research paper thumbnail of Review of: "What substances are adolescents vaping? Estimating nicotine-specific and marijuana-specific vaping from US national youth surveys

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Research paper thumbnail of Local dynamics and gravitational collapse of a self-gravitating magnetized Fermi gas

General Relativity and Gravitation, Nov 30, 2007

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Research paper thumbnail of Cosmological backreaction in spherical and plane symmetric dust-filled space-times

Classical and Quantum Gravity, Sep 18, 2019

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Research paper thumbnail of Thermodynamics of the Stephani Universes

Journal of Mathematical Physics, Mar 1, 1995

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Research paper thumbnail of A general relativistic approach to the Navarro–Frenk–White galactic halos

Classical and Quantum Gravity, Oct 30, 2004

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Research paper thumbnail of Evolution of radial profiles in regular Lemaître–Tolman–Bondi dust models

Classical and Quantum Gravity, Jul 16, 2010

Bookmarks Related papers MentionsView impact

Research paper thumbnail of On spherically symmetric shear‐free perfect fluid configurations (neutral and charged). I

Journal of Mathematical Physics, May 1, 1987

A class of solutions describing a wide variety of nonstatic, spherically symmetric, charged, shea... more A class of solutions describing a wide variety of nonstatic, spherically symmetric, charged, shear-free perfect fluid configurations is derived. It is presented in the form of Jacobian elliptic functions characterized by seven free parameters: five constants and two arbitrary functions of time. This class of solutions is the most general charged version of the class derived by Kustaanheimo and Qvist [Comment. Phys. Math. Helsingf. 13, 12 (1948); Exact Solutions of Einstein’s Field Equations (Cambridge U. P., Cambridge, 1980), Chap. 12, Sec. 2]. It is found that many of the charged particular solutions expressible by elementary functions are new. Particular solutions, including neutral and uniform density solutions, are classified in detail. The physical interpretation of these solutions, including the study of their singularity structure, will be presented in a subsequent paper (Part II).

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Scalar field “mini-MACHOs”: A new explanation for galactic dark matter

Physical review, Aug 26, 2004

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Research paper thumbnail of Conformal structure of a Schwarzschild black hole immersed in a Friedman universe

General Relativity and Gravitation, Mar 1, 1985

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Research paper thumbnail of Back-reaction and effective acceleration in generic LTB dust models

Classical and Quantum Gravity, Nov 4, 2011

Bookmarks Related papers MentionsView impact

Research paper thumbnail of On spherically symmetric shear‐free perfect fluid configurations (neutral and charged). II. Equation of state and singularities

Journal of Mathematical Physics, Apr 1, 1988

Geometrical and physical properties of the solutions derived and classified in Part I [J. Math. P... more Geometrical and physical properties of the solutions derived and classified in Part I [J. Math. Phys. 28, 1118 (1987)] are examined in detail. It is shown how the imposition of zero shear restricts the possible choices of equations of state. Two types of singular boundaries arising in these solutions are examined by verifying the local behavior of causal curves approaching these boundaries. For this purpose, a criterion due to C. J. S. Clarke (private communication) is given, allowing one to test the completeness of arbitrary accelerated timelike curves in terms of their acceleration and proper time. One of these boundaries is a spacelike singularity at which causal curves terminate as pressure diverges but matter-energy and charge densities remain finite. At the other boundary, which is timelike if the expansion Θ is finite, proper volume of local fluid elements vanishes as all state variables diverge but causal curves are complete. If Θ diverges at this boundary, a null singularity arises as the end product of the collapse of a two-sphere generated by a given class of timelike curves. The gravitational collapse of bounded spheres matched to a Schwarzschild or Reissner–Nordstro/m exterior is also examined in detail. It is shown that the spacelike singularity mentioned above could be naked under certain parameter choices. Solutions presenting the other boundary produce very peculiar black holes in which the ‘‘surface’’ of the sphere collapses into the above mentioned null singularity, while the ‘‘interior’’ fluid layers avoid this singularity and evolve towards their infinite future.

Bookmarks Related papers MentionsView impact