arXiv subjects
Publications and source records attributed to Akihiro Nakamura.
The phase structure of hadrons and quark-gluon plasma is investigated by two types of equation of hadron state, namely ideal hadron gas model and the compressible bag model. It is pointed out that, while the ideal gas model produces unrealistic extra hadron phase, the compressible bag model gives an expected and reasonable phase diagram even if rich hadron spectrum is taken into account.
We propose a mechanism to trap massive vector fields as a photon on the Randall-Sundrum brane embedded in the five dimensional AdS space. This localization-mechanism of the photon is realized by considering a brane action, to which a quadratic potential of the bulk-vector fields is added. We also point out that this potential gives several constraints on the fluctuations of the vector fields in the bulk space.
We address the behaviour of the scalar field with negative mass squared in the five dimensional AdS space where the Randall-Sundrum brane-world is embedded. We point out that the tachyonic scalar allowed in the bulk space destabilizes the embedded brane-world where the cosmological constant is zero. The resolution of this instability is discussed from the viewpoint of AdS/CFT correspondence.
The evolution of matter produced in nucleus collisions is investigated in the frame work of the simplified fluid equation, where the compressible bag model is used as the equation of state for hadrons. It is shown that the quark-gluon phase is easily achieved in RHIC experiments, and that the typical structure of the phase transition, however, may be difficult to observe in simple analyses of $ $ data.