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arXiv 2006.00494gr-qchep-th
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半经典爱因斯坦方程:降到基态

Semi-classical Einstein equations:descend to the ground state

Zbigniew Haba

摘要:

依赖于时间的宇宙学项来自于在不同于基态的状态下计算的能量-动量张量。本文讨论了在各种近似纯态和混合态下爱因斯坦方程的能量动量张量的期望值。我们应用经典的慢滚场演化以及Starobinsky和暖膨胀随机方程来计算期望值。我们表明,在一个国家集中在当地的最大值的双阱势的期望值呈指数下降。在随机通货膨胀模型中,我们证明了期望值的下降。我们计算了宇宙学常数$Λ$在大时间作为期望值的能量密度相对于平稳的概率分布。我们证明了$Λ\simeq γ^{\frac{4}{3}} where $ γ$是热耗散率。

英文摘要:

The time-dependent cosmological term arises from the energy-momentum tensor calculated in a state different from the ground state. We discuss the expectation value of the energy-momentum tensor on the rhs of Einstein equations in various (approximate)pure as well as mixed states. We apply the classical slow-roll field evolution as well as the Starobinsky and warm inflation stochastic equations in order to calculate the expectation value. We show that in a state concentrated at the local maximum of the double-well potential the expectation value is decreasing exponentially. We confirm the descend of the expectation value in the stochastic inflation model. We calculate the cosmological constant $Λ$ at large time as the expectation value of the energy density with respect to the stationary probability distribution. We show that $Λ\simeq γ^{\frac{4}{3}} where $γ$ is the thermal dissipation rate.

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