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arXiv 1807.03522nucl-th
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非升压不变耗散流体动力学中的热噪声

Thermal noise in non-boost-invariant dissipative hydrodynamics

Chandrodoy Chattopadhyay, Subrata Pal

摘要:

研究了相对论性重离子碰撞中流体动力学涨落对物质非助推不变纵向膨胀的影响。我们制定了二阶粘性流体动力学内的热噪声理论,将噪声视为非升压不变流之上的扰动。建立了一个(1+1)维水动力演化的数值模拟模型。该代码进行了测试,以再现的黎曼解的真空中的物质膨胀的分析结果。对于粘性流体动力学膨胀,初始能量密度分布是通过再现RHIC能量下的带电强子快度分布得到的。我们表明,由时空相关的热噪声和由诱导的热扰动引起的纵向快度关联具有不同的结构。在一般情况下,快度关联被发现是由温度波动在小的快度分离和速度波动在大的快度。我们证明,热噪声产生脊状的两粒子快度相关,持续在适度大的rapidities。的相关性的大小和模式是相当敏感的各种二阶耗散形式主义和基本的状态方程,特别是在大rapidities。短程部分的快度相关被发现是有点增强相比,在助推不变的物质流。

英文摘要:

We study the effects of hydrodynamic fluctuations in non-boost-invariant longitudinal expansion of matter formed in relativistic heavy ion collisions. We formulate the theory of thermal noise within second-order viscous hydrodynamics treating noise as a perturbation on top of the non-boost-invariant flow. We develop a numerical simulation model to treat the (1+1)-dimension hydrodynamic evolution. The code is tested to reproduce the analytic results for the Riemann solver for expansion of matter in vacuum. For viscous hydrodynamic expansion, the initial energy density distribution are obtained by reproducing the measured charged hadron rapidity distribution at the RHIC energies. We show that the longitudinal rapidity correlations arising from space-time dependent thermal noise and from an induced thermal perturbation have distinct structures. In general, the rapidity correlations are found to be dominated by temperature fluctuations at small rapidity separation and velocity fluctuations at large rapidities. We demonstrate that thermal noise produce ridge-like two-particle rapidity correlations which persist at moderately large rapidities. The magnitude and pattern of the correlations are quite sensitive to various second-order dissipative formalisms and to the underlying equations of state, especially at large rapidities. The short-range part of the rapidity correlation is found to be somewhat enhanced as compared to that in boost-invariant flow of matter.

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