The Unruh effect for a massless scalar field in (1 + 1)D space-time is considered. It is shown that, under some natural assumptions like finiteness of the integration volume or finiteness of the interaction (propagation of information) speed, the Unruh effect should be anisotropic. This property is not connected with a particular detector design but is fundamental like the Unruh effect itself. This consideration can be generalized to the case of massless and massive particles in (3 + 1)D space-time. The obtained result and its further development may be important for specific applications of the Hawking-Unruh effect such as the description of black hole evaporation and motion dynamics of accelerated bodies.

中文翻译：

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关于Unruh辐射的可能各向异性。第一部分：（1 + 1）D时空中的无质量标量场

考虑（1 +1）D时空中无质量标量场的Unruh效应。结果表明，在一些自然假设下，例如积分体积的有限性或相互作用（信息传播）速度的有限性，Unruh效应应该是各向异性的。此属性与特定的检测器设计无关，但与Unruh效应本身一样，是基本的。这种考虑可以推广到（3 +1）D时空中无质量和大质量粒子的情况。获得的结果及其进一步的发展对于霍金-安鲁特效应的特定应用（例如黑洞蒸发的描述和加速物体的运动动力学）可能是重要的。