标题： 与其他宇宙的碰撞：WMAP数据的最佳分析 显示英文标题

标题： Collisions with other Universes: the Optimal Analysis of the WMAP data

摘要： 一个有吸引力的理论是，我们当前的宇宙区域是从一个假真空永恒暴胀相中形成的核化气泡诞生的。 我们通过寻找当另一个气泡“宇宙”与我们的宇宙碰撞时在CMB上留下的信号来寻找该理论的证据。 我们在WMAP 7年数据中创建了一个高效且最优的信号估计器。 我们未发现可检测的信号，并限制了由碰撞产生的初始曲率扰动的幅度 a：-4.66 \times 10^{-8} < a (\sin{\thetabubble})^{4/3} < 4.73 \times 10^{-8} [Mpc^{-1}] 在 95% 置信度下，其中 \thetabubble 是气泡信号的角半径。 显示英文摘要

摘要： An appealing theory is that our current patch of universe was born as a nucleation bubble from a phase of false vacuum eternal inflation. We search for evidence for this theory by looking for the signal imprinted on the CMB that is generated when another bubble "universe" collides with our own. We create an efficient and optimal estimator for the signal in the WMAP 7-year data. We find no detectable signal, and constrain the amplitude, a, of the initial curvature perturbation that would be generated by a collision: -4.66 \times 10^{-8} < a (\sin{\thetabubble})^{4/3} < 4.73 \times 10^{-8} [Mpc^{-1}] at 95% confidence where \thetabubble is the angular radius of the bubble signal.