1,494 research outputs found
Gravity from the entropy of light
The holographic principle, considered in a semiclassical setting, is shown to
have direct consequences on physics at a fundamental level. In particular, a
certain relation is pointed out to be the expression of holography in basic
thermodynamics. It is argued moreover that through this relation holography can
be recognized to induce gravity, and an expression for the gravitational
lensing is obtained in terms of entropy over wavelength of black-body
radiation, or, at a deeper level, in terms of maximum entropy over associated
space to the elementary bit of information.Comment: 7 pages; v2: completion of the list of references; v3: the discussion
is divided in Sections and the argument is described in more detail; v4: a
statement is added (below eq.13) on what is the supposed difference between
Jacobson's work in ref.21 and this attempt; addition of a paragraph in last
Sectio
Entropy bounds and field equations
For general metric theories of gravity, we compare the approach that
describes-derives the field equations of gravity as a thermodynamic identity
with the one which looks at them from entropy bounds. The comparison is made
through the consideration of the matter entropy flux across (Rindler) horizons,
studied by making use of the notion of a limiting thermodynamic scale of
matter, previously introduced in the context of entropy bounds.
In doing this: i) a bound for the entropy of any lump of matter with a given
energy-momentum tensor is considered, in terms of a quantity which is
independent of the theory of gravity we use; this quantity is the variation of
the Clausius entropy of a suitable horizon when the element of matter crosses
it; ii) by making use of the equations of motion of the theory, the same
quantity is then expressed as the variation of Wald's entropy of that horizon
(and this leads to a generalized form of the generalized covariant entropy
bound, applicable to general diffeomorphism-invariant theories of gravity);
iii) a notion of for horizons, and an expression for it, is given.Comment: 8 pages, 1 figure; v4: some typos corrected, one reference and some
clarifications added, some editin
IKT approach for quantum hydrodynamic equations
A striking feature of standard quantum mechanics is its analogy with
classical fluid dynamics. In particular it is well known the Schr\"{o}dinger
equation can be viewed as describing a classical compressible and non-viscous
fluid, described by two (quantum) fluid fields {\rho ,% \mathbf{V}} , to be
identified with the quantum probability density and velocity field. This
feature has suggested the construction of a phase-space hidden-variable
description based on a suitable inverse kinetic theory (IKT; Tessarotto et al.,
2007). The discovery of this approach has potentially important consequences
since it permits to identify the classical dynamical system which advances in
time the quantum fluid fields. This type of approach, however requires the
identification of additional fluid fields. These can be generally identified
with suitable directional fluid temperatures (for ), to be
related to the expectation values of momentum fluctuations appearing in the
Heisenberg inequalities. Nevertheless the definition given previously for them
(Tessarotto et al., 2007) is non-unique. In this paper we intend to propose a
criterion, based on the validity of a constant H-theorem, which provides an
unique definition for the quantum temperatures.Comment: Contributed paper at RGD26 (Kyoto, Japan, July 2008
Isolated tau leptons in events with large missing transverse momentum at HERA
A search for events containing isolated tau leptons and large missing
transverse momentum, not originating from the tau decay, has been performed
with the ZEUS detector at the electron-proton collider HERA, using 130 pb^-1 of
integrated luminosity. A search was made for isolated tracks coming from
hadronic tau decays. Observables based on the internal jet structure were
exploited to discriminate between tau decays and quark- or gluon-induced jets.
Three tau candidates were found, while 0.40 +0.12 -0.13 were expected from
Standard Model processes, such as charged current deep inelastic scattering and
single W-boson production. To search for heavy-particle decays, a more
restrictive selection was applied to isolate tau leptons produced together with
a hadronic final state with high transverse momentum. Two candidate events
survive, while 0.20 +-0.05 events are expected from Standard Model processes.Comment: 28 pages, 4 figures, 3 tables, accepted by Phys. Lett. B. Updated
with minor changes to the text requested by the journal refere
Observation of Scaling Violations in Scaled Momentum Distributions at HERA
Charged particle production has been measured in deep inelastic scattering
(DIS) events over a large range of and using the ZEUS detector. The
evolution of the scaled momentum, , with in the range 10 to 1280
, has been investigated in the current fragmentation region of the Breit
frame. The results show clear evidence, in a single experiment, for scaling
violations in scaled momenta as a function of .Comment: 21 pages including 4 figures, to be published in Physics Letters B.
Two references adde
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