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Bahman Khanpour

Publications and source records attributed to Bahman Khanpour.

2 recordsLinked to original sources

Holographic real and imaginary potentials of heavy quarkonium in Yang-Mills-dilaton black holes

Within the methods of the real and the imaginary potential for investigating the melting of a heavy quarkonium in the AdS/CFT correspondence, we study the effects of the dynamical exponent, the hyperscaling violation parameter, and the Yang-Mills charge on both methods in the hyperscaling violated Yang-Mills-dilaton metric background. In the real part of the potential, we find out that the dynamical exponent, the hyperscaling violation parameter, and the Yang-Mills charge increase the real potential and decrease the dissociation length, and hence the quarkonium dissociates easily. In the imaginary part of the potential, we show that the dynamical exponent, the hyperscaling violation parameter, and the Yang-Mills charge tend to decrease the thermal width, thus strengthening the suppression of the heavy quarkonium, and making the melting process easier. Also, we show that the obtained results from the real and imaginary potential methods are compatible and complementary.

hep-th

Gravitational Merging as a Possible Source for the Cosmological Accelerating

Gravitational merging (or clustering) of cosmic objects is regarded as a possible source of the extra-acceleration of the universe at large scale. The merging/clustering of cosmic objects introduces a correction term in the equation of state for the effective present cosmic fluid in the form of $P=wρ+bρ^2$. As a result, an alternative relation for the energy density includes over and under-dense regions is obtained that coincide with the conventional relation in the standard limit. By analogy with bubbles, the under-dense regions (voids) in the cosmic fluid is shown to provide the needed negative pressure. Invoking the observational constraint for the dark energy equation of state $w$, we show that the merging of voids will act as a possible source of extra-accelerating at large scale in comparison with non-merging cosmic gas.

astro-ph.CO