tag:blogger.com,1999:blog-22973357.post7862881159829063306..comments2023-09-27T07:44:19.769-04:00Comments on Sabine Hossenfelder: Backreaction: Can we use gravitational waves to rule out extra dimensions – and string theory with it? Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.comBlogger8125tag:blogger.com,1999:blog-22973357.post-23579455955732138312017-05-23T01:44:23.999-04:002017-05-23T01:44:23.999-04:00Gustavo,
Ruling out extra-dimensions is pretty mu...Gustavo,<br /><br />Ruling out extra-dimensions is pretty much the only way to rule out string theory (at low energies). I agree with you of course that it wouldn't be as easy as my blogpost might have made it sound because many other possible explanations for the absence of a signal would have to be ruled out. Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-89158324263108034872017-05-22T04:03:16.268-04:002017-05-22T04:03:16.268-04:00As the second author of the paper in question I fu...As the second author of the paper in question I fully agree with Olivier's comment (first comment here above), particularly with his first point. Moreover, I believe the whole point of vue of your post is a little forced. Talking about falsifying string theory on the basis of our analysis is quite a stretch, to say the least, and I don't think this viewpoint conveys the message very well Anonymoushttps://www.blogger.com/profile/04054295664157929671noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-62776490182113168352017-05-20T21:22:07.823-04:002017-05-20T21:22:07.823-04:00With the exception that this is not KK but a warpe...With the exception that this is not KK but a warped compactification.<br /><br />KK ansatz is a direct product (e.g. M₄ x S¹) for the vacuum but you always get moduli in the uncompactified directions. <br /><br />To stabilize e.g. via flux compactification you have to use Warped ansatz (due to the flux you can't have a direct product anymore) where you have a warp factor in front of the line Giotishttps://www.blogger.com/profile/01538762241438887298noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-35431361265534271292017-05-19T11:30:24.287-04:002017-05-19T11:30:24.287-04:00Bill,
The number of dimensions is a parameter and...Bill,<br /><br />The number of dimensions is a parameter and a specific number is necessary to 'make it work' and I think I really don't understand the question.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-88401184710103197512017-05-19T10:51:37.651-04:002017-05-19T10:51:37.651-04:00"... extra dimensions add another way for gra..."<i>... extra dimensions add another way for gravitational waves to make space shape-shift, called a breathing mode. ...space expands and contracts as gravitational waves pass through, in addition to stretching and squishing.</i>" Expect added degrees of freedom in gravitational radiation orbital decay and elsewhere, yes?<br /><br />Pulsar binaries lack orbital decay anomalies. PSR Uncle Alhttps://www.blogger.com/profile/05056804084187606211noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-27941093941421970032017-05-19T10:42:42.385-04:002017-05-19T10:42:42.385-04:00Great post on a topic of much interest today, Dr. ...Great post on a topic of much interest today, Dr. Bee. I don't read New Scientist any more, and I am far to skeptical of string theory to buy into it (but mainly because I can't imagine Nature being so complicated). <br /><br />Question: might the extra dimensions in string theory just be a bunch of parameters needed to make it work, kind of like curve fitting data to a polynomial? Billhttps://www.blogger.com/profile/13243006930165511059noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-30622030578635495832017-05-19T08:15:20.855-04:002017-05-19T08:15:20.855-04:00Hi Olivier,
Thanks for pointing out, I have added...Hi Olivier,<br /><br />Thanks for pointing out, I have added a clarification on the first point. 2.) Interesting, I'll have a look at this!Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-2259149487744230102017-05-19T08:07:34.619-04:002017-05-19T08:07:34.619-04:00Hi Sabine,
very good post, thank you! I have two...Hi Sabine, <br /><br />very good post, thank you! I have two remarks on what you say they claim "While LIGO alone cannot do it because the measurement requires three independent detectors, soon upcoming experiments could either confirm or forever rule out extra dimensions – and kill string theory along the way."<br /><br />1/ Since one cannot predict the amplitude of the effects they Unknownhttps://www.blogger.com/profile/06031141191397448812noreply@blogger.com