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marcus

Science Advisor

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## Main Question or Discussion Point

By my judgment as a bystander watching from the sidelines, this is a fantastically high quality paper.

Unless someone finds an error---which I don't think they will.

It just came out.

http://arxiv.org/abs/hep-th/0702016

Sabine Hossenfelder

"We investigate the properties of multi-particle states in Deformed Special Relativity (DSR). Starting from the Lagrangian formalism with an energy dependent metric, the conserved Noether current is derived and is found to be additive in the usual way. This quantity had previously been discarded because it was correctly realized that it does no longer obey the DSR transformations. We identify the reason for this mismatch in the fact that DSR depends only on the extensive quantity of total four-momentum instead of the energy-momentum densities as would be appropriate for a field theory. We argue that the reason for the failure of DSR to reproduce the standard transformation behavior in the well established limits is due to the missing sensitivity to the volume inside which energy is accumulated. We show that the soccer-ball problem is absent if one formulates DSR instead for the field densities. As a consequence, estimates for predicted effects have to be corrected by many orders of magnitude. Further, we derive that the modified quantum field theory implies a locality bound."

We knew Bee (as "Hossi") even before she started her blog and moved from SantaBar to Perimeter and got married etc. She used to post here at PF, and seemed to like to argue a lot. We can rightly be proud of this.

The new paper shows you what Perimeter got away from KITP or UCSB, someone who can do actually useful research. This paper (if someone doesnt find an error) actually FURTHERS things. It advances the parade.

Unless someone finds an error---which I don't think they will.

It just came out.

http://arxiv.org/abs/hep-th/0702016

**Multi-Particle States in Deformed Special Relativity**Sabine Hossenfelder

"We investigate the properties of multi-particle states in Deformed Special Relativity (DSR). Starting from the Lagrangian formalism with an energy dependent metric, the conserved Noether current is derived and is found to be additive in the usual way. This quantity had previously been discarded because it was correctly realized that it does no longer obey the DSR transformations. We identify the reason for this mismatch in the fact that DSR depends only on the extensive quantity of total four-momentum instead of the energy-momentum densities as would be appropriate for a field theory. We argue that the reason for the failure of DSR to reproduce the standard transformation behavior in the well established limits is due to the missing sensitivity to the volume inside which energy is accumulated. We show that the soccer-ball problem is absent if one formulates DSR instead for the field densities. As a consequence, estimates for predicted effects have to be corrected by many orders of magnitude. Further, we derive that the modified quantum field theory implies a locality bound."

We knew Bee (as "Hossi") even before she started her blog and moved from SantaBar to Perimeter and got married etc. She used to post here at PF, and seemed to like to argue a lot. We can rightly be proud of this.

The new paper shows you what Perimeter got away from KITP or UCSB, someone who can do actually useful research. This paper (if someone doesnt find an error) actually FURTHERS things. It advances the parade.