7 Matching Annotations
  1. Feb 2022
    1. Based on that lived, visceral experience, I’ve tried to pay more attention to the feeling of momentum when I get it, and really lean into it.

      Not everyone has a job where they can drop what they're doing and go work on something more interesting. But being able to switch gears to lean into creative momentum can help to increase and encourage productivity with respect to creative work and endeavors. This switching can be dramatically facilitated by having a wealth of alternate interesting options to delve into.

  2. Jan 2022
    1. We might stumble across the above unanswered HQ&A note. Giving us a starting point can use it as a springboard to make the research and writing process faster. That's all part of achieving more with less by using yesterday's momentum.

      Remembering and being able to more quickly recall prior contexts allows our thinking to build momentum.

  3. Jan 2021
  4. Jan 2019
    1. Similarly, “momentum” is only meaningful as a materialarrangement involving movable parts.

      We are who/what we are in relation to others as a collective entity. I appreciate the"momentum" phrase -- suggests this constant driving force of moving forward.

  5. May 2018
    1. Nos artigos arXiv:1503.00508 e arXiv:1408.3893 os autores provam que a energia ADM e o centro de massa intrínseco podem ser redefinidos em termos do tensor de Einstein. A origem dessa expressão pra energia ADM em termos do tensor de Einstein é atribuída ao Ashtekar e a Hansen, cujo trecho do artigo que trata desse assunto destaco nessa nota. O Piotr Chruściel também menciona essa expressão nesse trecho de um dos seus artigos.

      Gostaria de esclarecer o argumento que leva o Ashtekar e a Hansen a essa expressão. Quais são as razões físicas e geométricas?

    2. there is a natural vector space preserving isomorphism between the space of functions on I< and supertranslations on Spi, and that functions on l< which thus correspond to trans-lations are of the type (f(k))(1)) = ka1)a for some vector ka in the tangent space of iO. Consider the linear mapping f(k) -~ r 2 Eab(Dbf(k)kamndSW'n . s (23a) from the space of translations to the reals, where S2 is a 2-sphere cross section of the hyperboloid. Using the definition of f(k), it follows that DaD/Jf(k) '" -f(k)hab• Thus, D'lf(k) is a conformal Killing field on l<. Since Eab is both trace and divergence free, it follows that the integral in Eq. (22) is independent of the choice of the cross section. Thus, we have obtained a conserved quantity which takes values in the dual of the vector space of translations. This is the total 4-momentum. It is not difficult to show that this conserved quantity is essentially the same as the ADM 4-momentum. 6,3 (That is, the two agree when both are defined. )
    1. the ADM pw can be written in the Ashtekar-Hansen form [lo]?: ppXp = lim (1 (-det g)l/2~wvapXpxYRnPpu dxP A dx" r+m r=constant d((-det g)'/2&,,,px"XpgaYT~p dxp) (32~)-' +2 I r=constant ) = lim (i (-det g)l/2R,,apXpx" dS"@)(16~)-'