46,760 research outputs found
Hydrodynamical evolution near the QCD critical end point
Hydrodynamical calculations have been successful in describing global
observables in ultrarelativistic heavy ion collisions, which aim to observe the
production of the quark-gluon plasma. On the other hand, recently, a lot of
evidence that there exists a critical end point (CEP) in the QCD phase diagram
has been accumulating. Nevertheless, so far, no equation of state with the CEP
has been employed in hydrodynamical calculations. In this paper, we construct
the equation of state with the CEP on the basis of the universality hypothesis
and show that the CEP acts as an attractor of isentropic trajectories. We also
consider the time evolution in the case with the CEP and discuss how the CEP
affects the final state observables, such as the correlation length,
fluctuation, chemical freezeout, kinetic freezeout, and so on. Finally, we
argue that the anomalously low kinetic freezeout temperature at the BNL
Relativistic Heavy Ion Collider suggests the possibility of the existence of
the CEP.Comment: 13 pages, 12 figures, accepted for publication in Physical Review
Focusing and the Holographic Hypothesis
The ``screen mapping" introduced by Susskind to implement 't Hooft's
holographic hypothesis is studied. For a single screen time, there are an
infinite number of images of a black hole event horizon, almost all of which
have smaller area on the screen than the horizon area. This is consistent with
the focusing equation because of the existence of focal points. However, the
{\it boundary} of the past (or future) of the screen obeys the area theorem,
and so always gives an expanding map to the screen, as required by the
holographic hypothesis. These considerations are illustrated with several
axisymmetric static black hole spacetimes.Comment: 8 pages, plain latex, 5 figures included using psfi
Information Geometry of Entanglement Renormalization for free Quantum Fields
We provide an explicit connection between the differential generation of
entanglement entropy in a tensor network representation of the ground states of
two field theories, and a geometric description of these states based on the
Fisher information metric. We show how the geometrical description remains
invariant despite there is an irreducible gauge freedom in the definition of
the tensor network. The results might help to understand how spacetimes may
emerge from distributions of quantum states, or more concretely, from the
structure of the quantum entanglement concomitant to those distributions.Comment: 18 pages. 1 eps figure. References added. Some comments adde
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