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Nuclear Toeplitz operators between Fock spaces

Tengfei Ma, Yufeng Lu, Chao Zu

Abstract

We study Toeplitz operators with measure-valued symbols acting between Fock spaces. Given $1\le p,q\le\infty$ and a Borel measure $μ$ on $\mathbb C$, we investigate when the associated Toeplitz operator \[ T_μ: F^p_α\to F^q_α\] belongs to the nuclear class. For positive measures $μ$ and in the range $1\le q\le p\le\infty$, we obtain necessary and sufficient conditions for the nuclearity of $T_μ$ in terms of the Berezin transform of $μ$. As a consequence, nuclearity in this setting exhibits a rigidity property: if $T_μ$ is nuclear from $F^p_α$ to $F^q_α$ for some $q\le p$, then it is nuclear for all such $q$. In the case $p<q$, we show that the situation is more delicate. We provide separate necessary and sufficient conditions for nuclearity, indicating that the Berezin transform alone does not yield a complete characterization. The proofs rely on tools from Banach space operator theory combined with kernel estimates on Fock spaces. Our results extend naturally to Fock spaces on $\mathbb C^n$.

Nuclear Toeplitz operators between Fock spaces

Abstract

We study Toeplitz operators with measure-valued symbols acting between Fock spaces. Given and a Borel measure on , we investigate when the associated Toeplitz operator belongs to the nuclear class. For positive measures and in the range , we obtain necessary and sufficient conditions for the nuclearity of in terms of the Berezin transform of . As a consequence, nuclearity in this setting exhibits a rigidity property: if is nuclear from to for some , then it is nuclear for all such . In the case , we show that the situation is more delicate. We provide separate necessary and sufficient conditions for nuclearity, indicating that the Berezin transform alone does not yield a complete characterization. The proofs rely on tools from Banach space operator theory combined with kernel estimates on Fock spaces. Our results extend naturally to Fock spaces on .
Paper Structure (8 sections, 19 theorems, 107 equations)

This paper contains 8 sections, 19 theorems, 107 equations.

Key Result

Proposition 2.2

For $1<p<\infty$, the Fock space $F_\alpha^p$ is a Banach space that enjoys both the approximation property and the Radon--Nikodým property.

Theorems & Definitions (24)

  • Definition 2.1
  • Proposition 2.2
  • Theorem 2.3
  • Proposition 2.4
  • Proposition 2.5
  • Definition 3.1
  • Theorem 3.2
  • Lemma 3.3
  • Lemma 3.4
  • Theorem 3.5
  • ...and 14 more