Institute for Theoretical Physics, Universität Regensburg, D-93040 Regensburg, Germany and Department of Theoretical Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India.
Institute for Theoretical Physics, Universität Regensburg, D-93040 Regensburg, Germany.
Phys Rev Lett. 2014 Jan 31;112(4):042301. doi: 10.1103/PhysRevLett.112.042301. Epub 2014 Jan 29.
We determine the magnetization of quantum chromodynamics for several temperatures around and above the transition between the hadronic and the quark-gluon phases of strongly interacting matter. We obtain a paramagnetic response that increases in strength with the temperature. We argue that due to this paramagnetism, chunks of quark-gluon plasma produced in noncentral heavy ion collisions should become squeezed perpendicular to the magnetic field. This anisotropy will then contribute to the elliptic flow v2 observed in such collisions, in addition to the pressure gradient that is usually taken into account. We present a simple estimate for the magnitude of this new effect and a rough comparison to the effect due to the initial collision geometry. We conclude that the paramagnetic effect might have a significant impact on the value of v2.
我们确定了强相互作用物质的强子和夸克-胶子相之间的相变温度附近和以上的几个温度下的量子色动力学的磁化强度。我们得到了一个随着温度增强的顺磁响应。我们认为，由于这种顺磁性，在非中心重离子碰撞中产生的夸克-胶子等离子体的块状物应该在垂直于磁场的方向上被挤压。这种各向异性除了通常考虑的压力梯度外，还将导致在这种碰撞中观察到的椭圆流 v2。我们对这种新效应的大小进行了简单的估计，并与初始碰撞几何形状引起的效应进行了粗略比较。我们得出的结论是，顺磁效应可能对 v2 的值有重大影响。
