Charged Quantum Fields Associated with Endomorphisms of CAR and CCR Algebras
英文摘要:
Quasi-free endomorphisms of the CAR and CCR algebras are studied from the point of view of the theory of superselection sectors.
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Carsten Binnenhei
Quasi-free endomorphisms of the CAR and CCR algebras are studied from the point of view of the theory of superselection sectors.
机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。
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Recently it is proved in arXiv:1906.05493v1 [math.OA] that CCR flows over convex cones are cocycle conjugate if and only if the associated isometric representations are conjugate. We provide a very short, simple and direct proof of that. Using the same idea we prove the analogous statement for CAR flows as well. Further we show that CCR flows are not cocycle conjugate to the CAR flows when the (multi-parameter) isometric representation is `proper', a condition which is satisfied by all known examples.
Entropy of Bogoliubov automorphisms of CAR and CCR algebras with respect to quasi-free states
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Based on an embedding formula of the CAR algebra into the Cuntz algebra ${\mathcal O}_{2^p}$, properties of the CAR algebra are studied in detail by restricting those of the Cuntz algebra. Various $\ast$-endomorphisms of the Cuntz algebra are explicitly constructed, and transcribed into those of the CAR algebra. In particular, a set of $\ast$-endomorphisms of the CAR algebra into its even subalgebra are constructed. According to branching formulae, which are obtained by composing representations and $\ast$-endomorphisms, it is shown that a KMS state of the CAR algebra is obtained through the a…
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Previously, we have shown that the CAR algebra for fermions is embedded in the Cuntz algebra ${\cal O}_{2}$ in such a way that the generators are expressed in terms of polynomials in the canonical generators of the latter, and it coincides with the U(1)-fixed point subalgebra ${\cal A}\equiv {\cal O}_{2}^{U(1)}$ of ${\cal O}_{2}$ for the canonical gauge action. Based on this embedding formula, some properties of ${\cal A}$ are studied in detail by restricting those of ${\cal O}_{2}$. Various endomorphisms of ${\cal O}_{2}$, which are defined by polynomials in the canonical generators, are expl…
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We establish a generalisation of the fundamental state convertibility theorem in quantum information to the context of bipartite quantum systems modelled by commuting semi-finite von Neumann algebras. Namely, we establish a generalisation to this setting of Nielsen's theorem on the convertibility of quantum states under local operations and classical communication (LOCC) schemes. Along the way, we introduce an appropriate generalisation of LOCC operations and connect the resulting notion of approximate convertibility to the theory of singular numbers and majorisation in von Neumann algebras. A…
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