Holography of the QGP Reynolds number
The viscosity of the Quark–Gluon Plasma (QGP) is usually described holographically by the entropy-normalized dynamic viscosity η/s. However, other measures of viscosity, such as the kinematic viscosity ν and the Reynolds number Re, are often useful, and they too should be investigated from a hologra...
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| Format: | Article |
| Language: | English |
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Elsevier
2017-08-01
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| Series: | Nuclear Physics B |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0550321317301682 |
| Summary: | The viscosity of the Quark–Gluon Plasma (QGP) is usually described holographically by the entropy-normalized dynamic viscosity η/s. However, other measures of viscosity, such as the kinematic viscosity ν and the Reynolds number Re, are often useful, and they too should be investigated from a holographic point of view. We show that a simple model of this kind puts an upper bound on Re for nearly central collisions at a given temperature; this upper bound is in very good agreement with the observational lower bound (from the RHIC facility). Furthermore, in a holographic approach using only Einstein gravity, η/s does not respond to variations of other physical parameters, while ν and Re can do so. In particular, it is known that the magnetic fields arising in peripheral heavy-ion collisions vary strongly with the impact parameter b, and we find that the holographic model predicts that ν and Re can also be expected to vary substantially with the magnetic field and therefore with b. |
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| ISSN: | 0550-3213 1873-1562 |