#instanton — Public Fediverse posts

#paperOfTheDay is "Comparison between large-order estimates and perturbation series in a scalar field theory with Gaussian propagator" from 1978.
The perturbation series for small coupling in #quantumFieldTheory is usually divergent (because the theory with negative coupling describes different #physics and is not "smoothly" connected with the case of positive coupling). To obtain finite physical predictions for the positive coupling case, a #resummation is needed. In the 1970s and 1980s, the computational techniques were for the first time sufficient to reach, say, order 4 in perturbation series computed with #FeynmanDiagram s, and the question arose how to actually do the resummation in practice.
The present paper studies a model quantum field theory, where the propagator is exp(-p^2). This is not physically accurate, but it allows to compute perturbation series to very high order (order 8 here) because the #FeynmanIntegral s are easier. Secondly, one can carry out an #instanton calculation to determine the leading large-order growth. This allows to study whether or not the series coefficients match the expected growth rate, and how to use various different methods of resummation. In particular, the instanton analysis predicts the location and algebraic exponent for the leading singularity in the Borel plane, and this can be used as an additional input: Either, compute the Borel transform directly with a shifted-gamma function to account for the singularity, or make an ansatz of the type (known singularity)x(Pade approximant) for the Borel transformed function. The numerical data shows that this gives substantially higher accuracy for the resummation. https://journals.aps.org/prd/abstract/10.1103/PhysRevD.17.2144

2 act dramedy.

#AWS #HPE #Aruba #InstantOn

Looking back at an intense week at #IBMTechXchange2023 in Las Vegas. It was awesome to...

🗓 Meet a lot of great people, customers, partners and scientists
💡 Get inspired by new ideas to build on top of IBM tech
👨‍💻 Present and live demo #instanton and #EclipseStore
🏌‍♂️ Have fun at the evening events
🌆 Enjoy a great time in #lasvegas

THANKS to #ibm for the well-organised and valuable conference!

I am not sure why, but this new #Aruba #InstantOn switch I got will NOT stay connected to Aruba’s cloud management. If I plop it on another network it works fine, but on my primary house network? Nah. I’m running #Sophos firewalls on both networks, but there has to be something configured differently on my home network that is getting in the way.

In the end, I don’t really care and can manage the switch locally instead of via the cloud. BUT this is also a lot of hassle for a switch…shouldn’t be this hard to get it working. Also, I was wanting to compare it to #Ubiquiti but not being able to use the cloud features makes that test pointless…

Bother. ISP (SuperLoop) has enabled experimental IPv6, but router doesn’t support it. Router is bridged to a modem, so I guess I could just get another router and maintain the access points. #Aruba #InstantOn

This was a wild ride - whoa!

"Taking The Deepest Possible Breath", Gravis Again (https://cohost.org/cathoderaydude/post/1228730-taking-the-deepest-p).

On HN: https://news.ycombinator.com/item?id=35301800

#BIOS #Windows #Linux #InstantOn #Phoenix #Netbook #Hypervisor #FirstWare