226,715 research outputs found
Origin of synchronized traffic flow on highways and its dynamic phase transitions
We study the traffic flow on a highway with ramps through numerical
simulations of a hydrodynamic traffic flow model. It is found that the presence
of the external vehicle flux through ramps generates a new state of recurring
humps (RH). This novel dynamic state is characterized by temporal oscillations
of the vehicle density and velocity which are localized near ramps, and found
to be the origin of the synchronized traffic flow reported recently [PRL 79,
4030 (1997)]. We also argue that the dynamic phase transitions between the free
flow and the RH state can be interpreted as a subcritical Hopf bifurcation.Comment: 4 pages, source TeX file and 4 figures are tarred and compressed via
uufile
Gauge bosons and the AdS_3/LCFT_2 correspondence
We study the relationship between the gauge boson coupled to spin 2 operator
and the singleton in three-dimensional anti-de Sitter space(AdS). The
singleton can be expressed in terms of a pair of dipole ghost fields and
which couple to and operators on the boundary of AdS. These
operators form the logarithmic conformal field theory(LCFT). Using the
correlation function for logarithmic pair, we calculate the greybody factor for
the singleton. In the low temperature limit of , this is
compared with the result of the bulk AdS calculation of the gauge boson. We
find that the gauge boson cannot be realized as a model of the AdS/LCFT
correspondence.Comment: 9 pages, no figures, previous version should be replaced with this,
the result was reverse
- β¦