We define a proper effective temperature for relativistic nonequilibrium steady states (NESSs). A conventional effective temperature of NESSs is defined from the ratio of the fluctuation to the dissipation. However, NESSs have relative velocities to the heat bath in general, and hence the conventional effective temperature can be frame dependent in relativistic systems. The proper effective temperature is introduced as a frame-independent (Lorentz invariant) quantity that characterizes NESSs. We find that the proper effective temperature of NESSs is higher than the proper temperature of the heat bath in a wide range of holographic models even when the conventional effective temperature is lower than the temperature of the heat bath.

中文翻译：

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非平衡稳态的适当有效温度

我们为相对论非平衡稳态 (NESS) 定义了合适的有效温度。NESS 的常规有效温度由波动与耗散的比率定义。然而，NESS 通常相对于热浴具有相对速度，因此传统的有效温度在相对论系统中可能与框架有关。适当的有效温度被引入为表征 NESS 的框架无关（洛伦兹不变）量。我们发现，即使在常规有效温度低于热浴温度时，NESS 的适当有效温度也高于各种全息模型中的热浴适当温度。