https://hackerpaper.kaipfister.de/p/gr-qc_0604088/Collected HN comments and submissions linking this paper.enMon, 02 Nov 2026 11:16:22 GMThttps://news.ycombinator.com/item?id=28924344urn:hackerpapers:mention:gr-qc_0604088:28924344Tue, 19 Oct 2021 22:02:33 GMT<p>&gt; We remark that A_\mu also contains a pure vector mode perturbation which is expected to behave similarly as in the Einstein-Æther theory [90, 91]&quot; Their [91] is Jacobson &amp; Mattingly https://arxiv.org/abs/gr-qc/0007031 whose §VII (DISCUSSION) contains this, which I struggle to see as helpful for them: &quot;With the action adopted in this paper the aether vector generically develops gradient singularities even when the metric is perfectly regular. We take this as a sign that the theory is unphysical as an effective theory&quot;. (That doesn&#x27;t stop Jacobson from investigating things like…</p><p><a href="https://hackerpaper.kaipfister.de/p/gr-qc_0604088/">Paper and discussion history</a>. A mention is not an endorsement.</p>gr-qc