TheHatter

I think the whole surfaces have associated corner symmetries should lead to something at some point

Our website now includes talk recordings by group members and visitors!

For example, check out @crossproduct.bsky.social Lev's tutorial on von Neumann algebras from earlier this month, and a talk by DESY's Enrico Brehm on matrix model simulation from March.

www.physik.fu-berlin.de/en/einrichtu...

wtf

I thought about it and it is true, because local algebras are type III and they do, by definition, not contain rank I projections

You are completely right. There is a ONB of "position and time eigenstates" but it doesn't form an lorentz rep. Another thing I want to mention, which I think would anyway kill my proposal, is that I doubt that the projection phi(x)|0><0|phi(x) is an element of the local algebra of observables

yeah I confused the commutator of phi with itself with the one with the momentum when I made that statement..

you are right I was confused

I agree that it is an overcomplete basis, but since I will do a measurement at different times I do not care, because the states describing locallized excitations at a fixed time are orthogonal and thats all I care about for measurements

I think the following is more accurate: For each fixed time, they will be orthogonal because of causality but you have a different basis for each time and at each time t the basis does describe particles at location x at time t. And LT will transform the bases between times into each other.

All I want to say is that I still think there are states that are perfectly reasonable to be thought of as describing a fixed number of localized particles.

You can do it for 1-particle states because you 1-particle space (for a scalar field) is just L^2(R^d) and for n-particle states you can appropriately generalized this via (symmetrized) tensor products of the 1-particle position basis.

What operator do you call N(U)?
I think it depends on what features you want a state to have, for it to describe a "localized excitation" and I guess I am ok with just using the standard QM way of saying it describes a state with a wavefunction that is supported in the region in question.

The particle is localized the moment the state was a localized wave packet of 1-particle states no?

On Infinite Tensor Networks, Complementary Recovery and Type II Factors We initiate a study of local operator algebras at the boundary of infinite tensor networks, using the mathematical theory of inductive limits. In particular, we consider tensor networks in which each ...

Von Neumann algebras have had a recent comeback in holographic dualities: The type of a boundary (sub-)algebra reveals properties of their bulk dual.

In our new work, we show that limits of tensor network codes lead to very similar algebraic structures!
arxiv.org/abs/2504.00096

Never heard someone use "lernen" for teaching. I could imagine that maybe one could confuse "lehren" and "lernen". the former literally means "teach"

Ted Lasso is coming back for season 4 Believe.

Ted Lasso is coming back for season 4

This also works for the Church-Turing thesis and its generalizations

There is this story that Gödel found a loophole in the constitution to implement a dictatorship in the USA and I am wondering for some time now if he foresaw Trump lol

Well I think right now it is bleeding out in a nice room with the corpse to be being livestreamed around the globe

One fifth of us germans however do elect openly racist people

Its frightening really where all this is going

The American Mathematical Society has also started a page to coordinate support for professional mathematics, so far focusing on executive orders impacting the National Science Foundation: www.ams.org/government/g...

on approaching hard problems Friends, colleagues, and lovers of words, I usually use this space to talk about books, but today I want to tell you about my friend Adriana Salerno. Like...

My friend @mathyadriana.bsky.social lost her job last week, and I want you to know the story:

buttondown.com/yarntheory/a...

The amount of internet trash information that lacks any credible evidence he believes is depressing

This is a submission that is particularly close to my heart, having spent so much time with #entanglementtheory early in my career.

scirate.com/arxiv/2502.1...

If one accepts that all entanglement manipulation actually has to be #efficient, it is all different.

I'm hiring a postdoc in quantum condensed matter theory! This will be a 3 year position, with a focus on developing and using novel numerical techniques to investigate open quantum systems.

For further info and to apply, see the following: elxw.fa.em3.oraclecloud.com/hcmUI/Candid...

sounds stupid

Oh amazing, congrats! The nature surrounding Pisa is beautiful!

I think the person making the list is confused.

Do they really think that industry research is less risk averse than university research or why do they want the bulk of grants to go to industry?