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We prove the existence of a complex valued $C^2$-function on the unit circle, a unitary operator U and a self-adjoint operator Z in the Hilbert-Schmidt class $S^2$, such that the perturbated operator $$ f(e^{iZ}U)-f(U)…

Functional Analysis · Mathematics 2015-09-03 Clément Coine , Christian Le Merdy , Denis Potapov , Fedor Sukochev , Anna Tomskova

Let $A$ be a selfadjoint operator in a separable Hilbert space, $K$ a selfadjoint Hilbert-Schmidt operator, and $f\in C^n(\mathbb{R})$. We establish that $\varphi(t)=f(A+tK)-f(A)$ is $n$-times continuously differentiable on $\mathbb{R}$ in…

Functional Analysis · Mathematics 2018-09-18 Clément Coine , Christian Le Merdy , Anna Skripka , Fedor Sukochev

Koplienko \cite{Ko} found a trace formula for perturbations of self-adjoint operators by operators of Hilbert-Schmidt class $\mathcal{B}_2(\mathcal{H})$. Later, Neidhardt introduced a similar formula in the case of pair of unitaries…

Functional Analysis · Mathematics 2024-04-04 Arup Chattopadhyay , Soma Das , Chandan Pradhan

In this paper, we extend the class of admissible functions for the trace formula of the second order in the self-adjoint, unitary, and contraction cases for a perturbation in the Hilbert-Schmidt class $\mathcal{S}^2(\mathcal{H})$ by…

Functional Analysis · Mathematics 2024-12-03 Arup Chattopadhyay , Clément Coine , Saikat Giri , Chandan Pradhan

Koplienko [Ko] found a trace formula for perturbations of self-adjoint operators by operators of Hilbert Schmidt class $\bS_2$. A similar formula in the case of unitary operators was obtained by Neidhardt [N]. In this paper we improve their…

Functional Analysis · Mathematics 2007-05-23 Vladimir Peller

Koplienko gave a trace formula for perturbations of self-adjoint operators by operators of Hilbert-Schmidt class $\mathcal{B}_2(\mathcal{H})$. Recently Gesztesy, Pushnitski and Simon gave an alternative proof of the trace formula when the…

Functional Analysis · Mathematics 2012-04-03 Arup Chattopadhyay , Kalyan B. Sinha

Koplienko \cite{Ko} found a trace formula for perturbations of self-adjoint operators by operators of Hilbert-Schmidt class $\mathcal{B}_2(\mathcal{H})$. Later in 1988, a similar formula was obtained by Neidhardt \cite{NH} in the case of…

Functional Analysis · Mathematics 2020-10-09 Arup Chattopadhyay , Soma Das , Chandan Pradhan

The paper establishes the Krein and Koplienko trace formulas for multivariable operator functions on symmetrically normed ideals of bounded operators. Results are proved for self-adjoint and maximal dissipative operators. They cover both…

Functional Analysis · Mathematics 2026-05-18 Arup Chattopadhyay , Saikat Giri , Chandan Pradhan , Alexandr Usachev

We give a new proof of the boundedness of bilinear Schur multipliers of second order divided difference functions, as obtained earlier by Potapov, Skripka and Sukochev in their proof of Koplienko's conjecture on the existence of higher…

Classical Analysis and ODEs · Mathematics 2025-01-29 Martijn Caspers , Jesse Reimann

Let $\mathcal{M}$ be a semifinite von Neumann algebra equipped with a normal faithful semifinite trace $\tau$, and let $L_p(\mathcal{M})$ denote the associated noncommutative $L_p$-space for $1<p<\infty$. Let $n\in\mathbb{N}$ and let $a, b$…

Operator Algebras · Mathematics 2026-02-18 Arup Chattopadhyay , Clément Coine , Saikat Giri , Chandan Pradhan

Let $G$ be a locally compact unimodular group, and let $\phi$ be some function of $n$ variables on $G$. To such a $\phi$, one can associate a multilinear Fourier multiplier, which acts on some $n$-fold product of the non-commutative…

Functional Analysis · Mathematics 2022-11-09 Martijn Caspers , Amudhan Krishnaswamy-Usha , Gerrit Vos

Given Hilbert spaces $H_1,H_2,H_3$, we consider bilinear maps defined on the cartesian product $S^2(H_2,H_3)\times S^2(H_1,H_2)$ of spaces of Hilbert-Schmidt operators and valued in either the space $B(H_1,H_3)$ of bounded operators, or in…

Operator Algebras · Mathematics 2020-07-09 Christian Le Merdy , Ivan G. Todorov , Lyudmila Turowska

Let $\Sigma\subset\mathbb{R}^d$ be a $C^\infty$-smooth closed compact hypersurface, which splits the Euclidean space $\mathbb{R}^d$ into two domains $\Omega_\pm$. In this note self-adjoint Schr\"odinger operators with $\delta$ and…

Spectral Theory · Mathematics 2024-06-17 Jussi Behrndt , Matthias Langer , Vladimir Lotoreichik

In this paper, we solve a spectral problem about positive semi-definite trace-class pseudodifferential operators on modulation spaces which was posed by H. Feichtinger. Later, C. Heil and D. Larson rephrased the problem in the broader…

Classical Analysis and ODEs · Mathematics 2018-12-11 Radu Balan , Kasso A. Okoudjou , Anirudha Poria

A natural generalization of Krein's theorem to a pair of commuting tuples $\left(H_1^0,H_2^0\right)$ and $\left(H_1,H_2\right)$ of bounded self-adjoint operators in a separable Hilbert space $\mathcal{H}$ with $H_j-H_j^0 = V_j\in…

Functional Analysis · Mathematics 2014-05-07 Arup Chattopadhyay , Kalyan B. Sinha

Let $M$ be a von Neumann algebra equipped with a normal semi-finite faithful trace (nsf trace in short) and let $T\colon M\to M$ be a contraction. We say that $T$ is absolutely dilatable if there exist another von Neumann algebra $M'$…

Operator Algebras · Mathematics 2025-02-05 Charles Duquet , Christian Le Merdy

The main result of the paper is that the Lifshits--Krein trace formula cannot be generalized to the case of functions of noncommuting self-adjoint operators. To prove this, we show that for pairs $(A_1,B_1)$ and $(A_2,B_2)$ of bounded…

Functional Analysis · Mathematics 2019-01-29 A. B. Aleksandrov , V. V. Peller , D. S. Potapov

We consider the difference $f(-\Delta +V)-f(-\Delta)$ of functions of Schr\"odinger operators in $L^2(\mathbb R^d)$ and provide conditions under which this difference is trace class. We are particularly interested in non-smooth functions…

Spectral Theory · Mathematics 2014-02-05 Rupert L. Frank , Alexander Pushnitski

We obtain general trace formulae in the case of perturbation of self-adjoint operators by self-adjoint operators of class $\bS_m$, where $m$ is a positive integer. In \cite{PSS} a trace formula for operator Taylor polynomials was obtained.…

Functional Analysis · Mathematics 2010-08-11 Alexei Aleksandrov , Vladimir Peller

We prove existence and multiplicity results for the fractional Schroedinger--Poisson--Slater equation $(-\Delta)^s u + (I_\alpha * u^2)u = f(|x|,u)$ in $\mathbb{R}^N$, where $0<s<1$ and $\alpha \in (1,N)$. We seek solutions in a fractional…

Analysis of PDEs · Mathematics 2025-11-10 Elisandra Gloss , Carlo Mercuri , Kanishka Perera , Bruno Ribeiro
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