Brown measure support and the free multiplicative Brownian motion
Brown measure support and the free multiplicative Brownian motion
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DOI:
10.1016/j.aim.2019.106771
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发表时间:
2018-09
影响因子:
1.7
通讯作者:
B. Hall;Todd Kemp
中科院分区:
文献类型:
--
作者:
B. Hall;Todd Kemp
The free multiplicative Brownian motion b t is the large-N limit of Brownian motion B t N on the general linear group GL (N; C). We prove that the Brown measure for b t—which is an analog of the empirical eigenvalue distribution for matrices—is supported on the closure of a certain domain Σ t in the plane. The domain Σ t was introduced by Biane in the context of the large-N limit of the Segal–Bargmann transform associated to GL (N; C). We also consider a two-parameter version, b s, t: the large-N limit of a related family of diffusion processes on GL (N; C) introduced by the second author. We show that the Brown measure of b s, t is supported on the closure of a certain planar domain Σ s, t, generalizing Σ t, introduced by Ho. In the process, we introduce a new family of spectral domains related to any operator in a tracial von Neumann algebra: the L p n-spectrum for n∈ N and p≥ 1, a subset of the ordinary spectrum defined relative to potentially-unbounded inverses. We show that, in general, the support of the Brown measure of an operator is contained in its L 2 2-spectrum.