Scattering matrix and functions of self-adjoint operators

نویسندگان

چکیده

منابع مشابه

Scattering Matrix and Functions of Self-adjoint Operators

In the scattering theory framework, we consider a pair of operators H0, H. For a continuous function φ vanishing at infinity, we set φδ(·) = φ(·/δ) and study the spectrum of the difference φδ(H − λ)− φδ(H0 − λ) for δ → 0. We prove that if λ is in the absolutely continuous spectrum of H0 and H, then the spectrum of this difference converges to a set that can be explicitly described in terms of (...

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Functions of Perturbed Noncommuting Self-adjoint Operators

Abstract. We consider functions f(A,B) of noncommuting self-adjoint operators A and B that can be defined in terms of double operator integrals. We prove that if f belongs to the Besov class B ∞,1 (R), then we have the following Lipschitz type estimate in the trace norm: ‖f(A1, B1)− f(A2, B2)‖S1 ≤ const(‖A1 −A2‖S1 + ‖B1 −B2‖S1). However, the condition f ∈ B ∞,1 (R) does not imply the Lipschitz ...

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Functions of self-adjoint operators in ideals of compact operators

For self-adjoint operators A,B, a bounded operator J , and a function f : R → C, we obtain bounds in quasi-normed ideals of compact operators for the difference f(A)J − Jf(B) in terms of the operator AJ − JB. The focus is on functions f that are smooth everywhere except for finitely many points. A typical example is the function f(t) = |t|γ with γ ∈ (0, 1). The obtained results are applied to d...

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Functions of Perturbed Tuples of Self-adjoint Operators

Abstract. We generalize earlier results of [2], [3], [6], [13], [14] to the case of functions of n-tuples of commuting self-adjoint operators. In particular, we prove that if a function f belongs to the Besov space B ∞,1(R ), then f is operator Lipschitz and we show that if f satisfies a Hölder condition of order α, then ‖f(A1 · · · , An)− f(B1, · · · , Bn)‖ ≤ constmax1≤j≤n ‖Aj −Bj‖ α for all n...

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Adjoints and Self-Adjoint Operators

Let V and W be real or complex finite dimensional vector spaces with inner products 〈·, ·〉V and 〈·, ·〉W , respectively. Let L : V → W be linear. If there is a transformation L∗ : W → V for which 〈Lv,w〉W = 〈v, Lw〉V (1) holds for every pair of vectors v ∈ V and w in W , then L∗ is said to be the adjoint of L. Some of the properties of L∗ are listed below. Proposition 1.1. Let L : V →W be linear. ...

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ژورنال

عنوان ژورنال: Journal of Spectral Theory

سال: 2011

ISSN: 1664-039X

DOI: 10.4171/jst/10