7:06 p.m.
Dear all,
I enjoyed last week's discussion session after the talk and thought some of you might
be interested in the following papers about magnetism and spontaneous symmetry breaking:
David Wallace (2018) Spontaneous Symmetry Breaking in Finite Quantum
Systems https://arxiv.org/abs/1808.09547
Jasper van Wezel (2019) An Introduction to Spontaneous Symmetry
Breaking https://arxiv.org/abs/1909.01820
Baptiste Savoie (2014) A rigorous proof of the Bohr-van Leeuwen theorem in the
semiclassical limit https://arxiv.org/abs/1403.2834v3
J.H. van Vleck (1977) Quantum Mechanics: the Key to Understanding
Magnetism https://www.nobelprize.org/uploads/2018/06/vleck-lecture.pdf
Also, during the discussion, the question arose of whether I consider spontaneous symmetry
breaking an experimental test of Everett. I don’t, but that being said, I think that
spontaneous symmetry breaking should be incorporated into decoherence theory, and that
decoherence theory aligns much more naturally with Everettian quantum theory than with
other frameworks.
–Sam
On 19 May 2023 at 14:29:56, William Schober (william.schober(a)usi.ch) wrote:
Hi everyone,
Next Wednesday, 24 May, at 14:30 in D5.01 we're happy to have Sam Kuypers from our
group give a talk at the CQI seminar. Sam will talk about the history of scientific models
of magnetism, and why decoherence plays an important role in their modern understanding.
Title and abstract below.
As always you can join us online at https://meet.jit.si/cqi-demon-M6QW9V7YY.
Looking forward to seeing you there,
Will
Speaker: Sam Kuypers
Title: On Magnets and the Multiverse
Abstract: Imagine a world where refrigerator magnets, compasses, and magnetic storage
devices don't exist. Surprisingly, this is precisely the universe implied by classical
physics: as Bohr and van-Leeuwen demonstrated, a classical system's magnetisation
invariably vanishes to zero in thermodynamic equilibrium.
Hence, quantum models, such as the Heisenberg spin-chain model, were invented to explain
the phenomenon of magnetism. In this talk, I shall explore those models' history and
intricacies. And I shall clarify why those quantum models require decoherence to explain
the structure of magnetic materials.