Physics Asked on January 2, 2022
I’m studying the book Techniques of Differential Topology in Relativity by Roger Penrose and I’m stuck in an exercise he left to the reader. We say that the spacetime $M$ is strongly causal in $p$ if and only if there exists an event $q$ such that $q prec p$ and for all events $x,y$ with $x ll p$ and $q ll y$ we have that $x ll y$. I have to show that in such a situation if $q ll p$, then there exists a closed trip (a timelike, future-oriented curve) through $p$. If anyone could help me with an answer or my thoughts below, I would be very grateful.
Here, $a ll b$ means that there exists a piecewise future-oriented timelike geodesic from $a$ to $b$, while $a prec b$ means that there exists a piecewise future-oriented causal geodesic, where the tangent vector is always null or timelike.
I tried many times but still can’t figure out how. One thing that came to my mind is that we could extend the trip from $q$ to $p$ to a point $p’$ and then apply the condition of strong causality with the same $q$ but I’m not quite sure that it is OK to do that. If you want deeper contextualization, you can look at lemma $4.16$ and remark $4.17$ of the book, on pages $31$ and $32$.
2 Asked on March 31, 2021 by v-poghosyan
3 Asked on March 31, 2021
0 Asked on March 31, 2021
3 Asked on March 31, 2021
2 Asked on March 31, 2021
2 Asked on March 31, 2021
definition electric current electrical resistance electricity electromagnetism
1 Asked on March 31, 2021
observables path integral quantum interpretations quantum mechanics
0 Asked on March 31, 2021
diffraction double slit experiment electrons quantum mechanics
1 Asked on March 31, 2021 by uitty400
2 Asked on March 31, 2021 by user291276
2 Asked on March 31, 2021 by kingkong
classical mechanics coupled oscillators linear algebra linear systems
4 Asked on March 31, 2021 by wifo215
education quantum computer quantum information quantum mechanics resource recommendations
1 Asked on March 31, 2021
1 Asked on March 31, 2021 by mathsnovice
1 Asked on March 31, 2021 by updownstrange
1 Asked on March 31, 2021
hilbert space homework and exercises notation perturbation theory quantum mechanics
1 Asked on March 31, 2021
2 Asked on March 31, 2021 by txema
Get help from others!
Recent Questions
Recent Answers
© 2023 AnswerBun.com. All rights reserved. Sites we Love: PCI Database, UKBizDB, Menu Kuliner, Sharing RPP