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- Thread starter Eytan Suchard
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Hi, the trace of the extrinsic tensor K(Myu,Nu) in Alcubierre metric, relative to the foliation normal vector is non zero on the rear x=rs+R (because it starts at negative rs) and front x=rs-R "walls". This is the normal volume component Tr =k(0,0)+k(1,1)+k(2,2)+k(3,3) and should affect the Ricci tensor in Lorentzian/Minkowsky 4D. How do we know that the Weyl tensor is also zero out of the walls ? In order for the middle of the bubble to experience 0 g, all elements of the Riemann tensor have to be zero, is that correct ? In other words, does gravity vanish out of the walls or only Ricci tensor vanishes our of the walls ? If it is only the Ricci tensor then gravity is not close to zero at x=rs as claimed. (Tanh((x+R)Sig)-Tanh((x-R)Sig))/Tanh(Sig R) gets a weak maximum at x = 0 for big Sig. The simple model of anti-energy at the rear wall and energy at the front, does not yield this function and does not yield 0 g at the center of the spaceship. The pilot will be sucked towards the front wall if the rear was pure negative energy and the front was pure positive energy. Can anyone describe the energy and anti-energy distribution in the rear wall and in the font wall ?

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is not fulfilled ? My intuition tells me yes and that the motion will be towards the left.

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berkeman

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is not fulfilled ? My intuition tells me yes and that the motion will be towards the left.

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You can see my original paper. In IOPScience and a more advanced paper in arXiv.

http://iopscience.iop.org/article/10.1088/1742-6596/845/1/012019

And a fix to (35) on page 22, and to appendix B, (B.1),(B.3),(B.7) in

https://arxiv.org/abs/1806.05244

Thank you, Eytan.

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