60,615 research outputs found
Radiation Pressure Supported Stars in Einstein Gravity: Eternally Collapsing Objects
Even when we consider Newtonian stars, i.e., stars with surface gravitational
redshift, z<< 1, it is well known that, theoretically, it is possible to have
stars, supported against self-gravity, almost entirely by radiation pressure.
However, such Newtonian stars must necessarily be supermassive. We point out
that this requirement for excessive large M, in Newtonian case, is a
consequence of the occurrence of low z<< 1. On the other hand, if we remove
such restrictions, and allow for possible occurrence highly general
relativistic regime, z >> 1, we show that, it is possible to have radiation
pressure supported stars at arbitrary value of M. Since radiation pressure
supported stars necessarily radiate at the Eddington limit, in Einstein
gravity, they are never in strict hydrodynamical equilibrium. Further, it is
believed that sufficiently massive or dense objects undergo continued
gravitational collapse to the Black Hole stage characterized by z =infty. Thus,
late stages of Black Hole formation, by definition, will have, z >> 1, and
hence would be examples of quasi-stable general relativistic RPSSs. This result
is also supported by with our previous finding that that trapped surfaces are
not formed in gravitational collapse and the value of the integration constant
in the vacuum Schwarzschild solution is zero. Hence the supposed observed BHs
are actually ECOs.Comment: Minor chages in proof. Discusses why the observed BHs are actually
ECOs and Chandrasekhar limit is not applicable to the
Direct Force In High Momentum Limit of QCD For Proton Physics
An explicit construction of the proton wave function is outlined in the high
momentum limit of QCD dominated by a direct force, one generated by
hooking the ends of a vertex to 3 distinct vertices, thus
making up a -shaped diagram (see fig.1). The high degree of symmetry
thus involved ensures that the wave function is a mixture of
and components, rather than the traditional and
type. Some results of this paradigm shift are offered.Comment: 6 pages, Presented at 4th International Symposium on Symmetries in
Subatomic Physics at NTU, Taipei, 200
Field-control, phase-transitions, and life's emergence
Instances of critical-like characteristics in living systems at each
organizational level as well as the spontaneous emergence of computation
(Langton), indicate the relevance of self-organized criticality (SOC). But
extrapolating complex bio-systems to life's origins, brings up a paradox: how
could simple organics--lacking the 'soft matter' response properties of today's
bio-molecules--have dissipated energy from primordial reactions in a controlled
manner for their 'ordering'? Nevertheless, a causal link of life's macroscopic
irreversible dynamics to the microscopic reversible laws of statistical
mechanics is indicated via the 'functional-takeover' of a soft magnetic
scaffold by organics (c.f. Cairns-Smith's 'crystal-scaffold'). A
field-controlled structure offers a mechanism for bootstrapping--bottom-up
assembly with top-down control: its super-paramagnetic components obey
reversible dynamics, but its dissipation of H-field energy for aggregation
breaks time-reversal symmetry. The responsive adjustments of the controlled
(host) mineral system to environmental changes would bring about mutual
coupling between random organic sets supported by it; here the generation of
long-range correlations within organic (guest) networks could include SOC-like
mechanisms. And, such cooperative adjustments enable the selection of the
functional configuration by altering the inorganic network's capacity to assist
a spontaneous process. A non-equilibrium dynamics could now drive the
kinetically-oriented system towards a series of phase-transitions with
appropriate organic replacements 'taking-over' its functions.Comment: 54 pages, pdf fil
Time-reversal and parity conservation for gravitating quarks
The complex mass term of a quark does not violate time-reversal or parity in
gravitational interactions, in spite of an axial anomaly.Comment: 4 pages, to appear in Classical and Quantum Gravit
Quantum Information Paradox: Real or Fictitious?
One of the outstanding puzzles of theoretical physics is whether quantum
information indeed gets lost in the case of Black Hole (BH) evaporation or
accretion. Let us recall that Quantum Mechanics (QM) demands an upper limit on
the acceleration of a test particle. On the other hand, it is pointed out here
that, if a Schwarzschild BH would exist, the acceleration of the test particle
would blow up at the event horizon in violation of QM. Thus the concept of an
exact BH is in contradiction of QM and quantum gravity (QG). It is also
reminded that the mass of a BH actually appears as an INTEGRATION CONSTANT of
Einstein equations. And it has been shown that the value of this integration
constant is actually zero. Thus even classically, there cannot be finite mass
BHs though zero mass BH is allowed. It has been further shown that during
continued gravitational collapse, radiation emanating from the contracting
object gets trapped within it by the runaway gravitational field. As a
consequence, the contracting body attains a quasi-static state where outward
trapped radiation pressure gets balanced by inward gravitational pull and the
ideal classical BH state is never formed in a finite proper time. In other
words, continued gravitational collapse results in an "Eternally Collapsing
Object" which is a ball of hot plasma and which is asymptotically approaching
the true BH state with M=0 after radiating away its entire mass energy. And if
we include QM, this contraction must halt at a radius suggested by highest QM
acceleration. In any case no EH is ever formed and in reality, there is no
quantum information paradox.Comment: 8 pages in Pramana Style, 6 in Revtex styl
A Dynamical Principle For 3D-4D Interlinkage In Salpeter-like Equations
The half-century old Markov-Yukawa Transversality Principle () which
provides a theoretical rationale for the covariant instantaneous approximation
() that underlies all Salpeter-like equations, is generalized to a
covariant null-plane ansatz (). A common characteristic of both
formulations is an exact 3D-4D interlinkage of BS amplitudes which facilitates
a two-tier description: the 3D form for spectroscopy, and the 4D form for
transition amplitudes as 4D loop integrals. Some basic applications of
on the covariant null plane (quark mass function, vacuum condensates, and decay
constants) are given on the lines of earlier applications to these processes
under .
PACS: 03.65.-w ; 03.65.Co ; 11.10.Qr ; 11.10.St
Keywords: Markov-Yukawa Transversality Principle (); Salpeter-like eqs;
Cov Instantaneity Ansatz (); Cov Null-Plane Ansatz (); 3D-4D
interlinkage; Vertex function; 4D loopsComment: LaTeX file, 25 pages, to be published in Nuclear Phys.
Theories with global gauge anomalies on the lattice
A global anomaly in a chiral gauge theory manifests itself in different ways
in the continuum and on the lattice. In the continuum case, functional
integration of the fermion determinant over the whole space of gauge fields
yields zero. In the case of the lattice, it is not even possible to define a
fermion measure over the whole space of gauge configurations. However, this is
not necessary, and as in the continuum, a reduced functional integral is
sufficient for the existence of the theory.Comment: Lattice 2000 (Topics in gauge theories); LaTeX with espcrc2, 4 page
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