Zobrazeno 1 - 10
of 200
pro vyhledávání: '"Klaus, Thomsen"'
Publikováno v:
Communications in Mathematical Physics. 393:1105-1123
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::93d3263fcab74951bd8910eb84437b8e
https://doi.org/10.1007/s00220-022-04386-x
https://doi.org/10.1007/s00220-022-04386-x
Autor:
Johannes Christensen, Klaus Thomsen
Publikováno v:
Christensen, J & Thomsen, K 2021, ' Random walks on groups and KMS states ', Monatshefte fur Mathematik, vol. 196, no. 1, pp. 15-37 . https://doi.org/10.1007/s00605-021-01573-1
A classical construction associates to a transient random walk on a discrete group $$\Gamma $$ a compact $$\Gamma $$ -space $$\partial _M \Gamma $$ known as the Martin boundary. The resulting crossed product $$C^*$$ -algebra $$C(\partial _M \Gamma )
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::beb2a66497d910327b4203cf3364bf3d
https://doi.org/10.1007/s00605-021-01573-1
https://doi.org/10.1007/s00605-021-01573-1
Autor:
Klaus Thomsen
Publikováno v:
Thomsen, K 2021, ' The Possible Temperatures for Flows on a Simple AF Algebra ', Communications in Mathematical Physics, vol. 386, no. 3, pp. 1489-1518 . https://doi.org/10.1007/s00220-021-04130-x
It is shown that for any infinite dimensional simple unital AF algebra A and any closed lower bounded set K of real numbers containing zero there is a flow on A for which the set of possible inverse temperatures is K.
Comment: v6: Various minor
Comment: v6: Various minor
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::13f53938a6f6cda63271d5a8da9ddc2a
https://pure.au.dk/portal/da/publications/the-possible-temperatures-for-flows-on-a-simple-af-algebra(3c927c1b-e385-4114-995c-b8b995e2259f).html
https://pure.au.dk/portal/da/publications/the-possible-temperatures-for-flows-on-a-simple-af-algebra(3c927c1b-e385-4114-995c-b8b995e2259f).html
Autor:
Klaus Thomsen
Publikováno v:
Thomsen, K 2021, ' Ground States for Generalized Gauge Actions on UHF Algebras ', Communications in Mathematical Physics, vol. 386, no. 1, pp. 57-85 . https://doi.org/10.1007/s00220-021-04075-1
We describe the structure of ground states and ceiling states for generalized gauge actions on an UHF algebra. It is shown that both sets are affinely homeomorphic to the state space of a unital AF algebra, and that any pair of unital AF algebras can
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::f39246add22d5bf7ad20af799c48c572
https://pure.au.dk/portal/da/publications/ground-states-for-generalized-gauge-actions-on-uhf-algebras(d71ca753-ba9c-4bd5-aef6-187170970798).html
https://pure.au.dk/portal/da/publications/ground-states-for-generalized-gauge-actions-on-uhf-algebras(d71ca753-ba9c-4bd5-aef6-187170970798).html
Autor:
Johannes Christensen, Klaus Thomsen
We provide a general description of the KMS states for flows whose fixed point algebra satisfies a certain regularity condition. This is then applied to crossed products by discrete groups, and in particular to certain flows on crossed products by di
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::789b2303902f6f5b72aa078c1b7bb09d
http://arxiv.org/abs/2006.14443
http://arxiv.org/abs/2006.14443
Autor:
Klaus Thomsen
Publikováno v:
Thomsen, K 2017, ' KMS weights on graph C*-algebras ', Advances in Mathematics, vol. 309, pp. 334-391 . https://doi.org/10.1016/j.aim.2017.01.024
KMS weights for generalized gauge actions on graph C*-algebras are studied and a complete description of the structure is obtained for the gauge action when the graph is strongly connected and has at most countably many exits. The structure is surpri
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::da1f90cda39aecfe91e6ba91bb2e39ef
https://doi.org/10.1016/j.aim.2017.01.024
https://doi.org/10.1016/j.aim.2017.01.024
Autor:
Johannes Christensen, Klaus Thomsen
Publikováno v:
Christensen, J & Thomsen, K 2022, ' KMS states on the crossed product C ∗-algebra of a homeomorphism ', Ergodic Theory and Dynamical Systems, vol. 42, no. 4, pp. 1373-1414 . https://doi.org/10.1017/etds.2020.141
Let $\varphi:X\to X$ be a homeomorphism of a compact metric space $X$. For any continuous function $F:X\to \mathbb{R}$ there is a one-parameter group $\alpha^{F}$ of automorphisms on the crossed product $C^*$-algebra $C(X)\rtimes_{\varphi}\mathbb{Z}$
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::90a1039fe1df3fe4cfa7e15dcaa164a9
Autor:
Klaus Thomsen
Publikováno v:
Thomsen, K 2020, ' Phase transition in the CAR algebra ', Advances in Mathematics, vol. 372, 107312 . https://doi.org/10.1016/j.aim.2020.107312
The paper develops a method to construct one-parameter groups of automorphisms on the CAR C*-algebra with a prescribed field of KMS states.
The third version fixes some typos and improves the exposition in a few places
The third version fixes some typos and improves the exposition in a few places
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::8219c46c6b85bb2f6b6811846285e92e
http://arxiv.org/abs/1810.01828
http://arxiv.org/abs/1810.01828
Autor:
Klaus Thomsen
Publikováno v:
Thomsen, K 2020, ' The factor type of dissipative KMS weights on graph C∗-algebras ', Journal of Noncommutative Geometry, vol. 14, no. 3, pp. 1107-1128 . https://doi.org/10.4171/JNCG/388
We calculate the S-invariant of Connes for the von Neumann algebra factors arising from KMS-weights of a generalized gauge action on a simple graph C*-algebra when the associated measure on the infinite path space of the graph is dissipative under th
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::744abbdf0781bae53150a0a20d895ec3
Autor:
Klaus Thomsen, Johannes Christensen
Publikováno v:
Thomsen, K & Christensen, J 2018, ' Equilibrium and ground states from Cayley graphs ', Journal of Functional Analysis . https://doi.org/10.1016/j.jfa.2017.06.019
We study the KMS states and $KMS_{\infty}$ states of generalized gauge actions on the $C^*$-algebra of a pointed Cayley graph. Our results provide information for any finitely generated group, but they are only complete for nilpotent groups.
Com
Com
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::be5bddd1db8e8f6cd32b26cf1dfef3fe
https://pure.au.dk/portal/da/publications/equilibrium-and-ground-states-from-cayley-graphs(f202ac98-f928-4767-bc73-bd80152ba6a9).html
https://pure.au.dk/portal/da/publications/equilibrium-and-ground-states-from-cayley-graphs(f202ac98-f928-4767-bc73-bd80152ba6a9).html