Wednesday, December 23, 2009

Classical and Quantum Gravity 2009

The most read articles of 2009 in the journal Classical and Quantum Gravity -- see under JULY :-)

What is a particle?
D Colosi and C Rovelli

Arithmetical chaos and quantum cosmology
L A Forte

Local Hawking temperature for dynamical black holes
S A Hayward, R Di Criscienzo, M Nadalini, L Vanzo and S Zerbini

The double pulsar system: a unique laboratory for gravity
M Kramer and N Wex

LISA Pathfinder: the experiment and the route to LISA
M Armano et al.

Status of NINJA: the Numerical INJection Analysis project
L Cadonati et al.

What is the entropy of the universe?
P H Frampton, S D H Hsu, T W Kephart and D Reeb

Testing gravitational-wave searches with numerical relativity waveforms: results from the first Numerical INJection Analysis (NINJA) project
B Aylott et al.

Polarized spots in anisotropic open universes
R Sung and P Coles

Present status of the Penrose inequality
M Mars

The information paradox: a pedagogical introduction
S D Mathur

Casimir energy and gravitomagnetism
F Sorge

What is the entropy of the universe?

P H Frampton, S D H Hsu, T W Kephart and D Reeb

Abstract. Standard calculations suggest that the entropy of our universe is dominated by black holes, whose entropy is of order their area in Planck units, although they comprise only a tiny fraction of its total energy. Statistical entropy is the logarithm of the number of microstates consistent with the observed macroscopic properties of a system, hence a measure of uncertainty about its precise state. Therefore, assuming unitarity in black hole evaporation, the standard results suggest that the largest uncertainty in the future quantum state of the universe is due to the Hawking radiation from evaporating black holes. However, the entropy of the matter precursors to astrophysical black holes is enormously less than that given by area entropy. If unitarity relates the future radiation states to the black hole precursor states, then the standard results are highly misleading, at least for an observer that can differentiate the individual states of the Hawking radiation.

1 comment:

Sabine Hossenfelder said...

Congratulations and Merry Christmas!


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