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We obtain a number of explicit estimates for quasi-norms of pseudo-differential operators in the Schatten-von Neumann classes $S_q$ with $0<q\le 1$. The estimates are applied to derive semi-classical bounds for operators with smooth or…

Spectral Theory · Mathematics 2022-01-27 Alexander V. Sobolev

This paper demonstrates the power of the calculus developed in the two previous parts of the series for all real forms of the almost Hermitian symmetric structures on smooth manifolds, including e.g. conformal Riemannian and almost…

Differential Geometry · Mathematics 2007-05-23 Andreas Cap , Jan Slovak , Vladimir Soucek

We prove almost Strichartz estimates found after adding regularity in the spherical coordinates for Schr\"odinger-like equations. The estimates are sharp up to endpoints. The proof relies on estimates involving spherical averages. Sharpness…

Analysis of PDEs · Mathematics 2019-12-03 Robert Schippa

The $J$-matrix method is extended to difference and $q$-difference operators and is applied to several explicit differential, difference, $q$-difference and second order Askey-Wilson type operators. The spectrum and the spectral measures…

Classical Analysis and ODEs · Mathematics 2014-04-17 Mourad E. H. Ismail , Erik Koelink

We establish lower bounds for the operator norms of the Fourier restriction/extension operators associated to monomial curves with affine arclength measure. Furthermore, we prove that the set of all extremizing sequences of such an operator…

Classical Analysis and ODEs · Mathematics 2024-11-19 Chandan Biswas , Betsy Stovall

We introduce a new framework that yields spectral bounds on norms of functions of transition maps for finite, homogeneous Markov chains. The techniques employed work for bounded semigroups, in particular for classical as well as for quantum…

Mathematical Physics · Physics 2015-03-16 Oleg Szehr , David Reeb , Michael M. Wolf

This paper deals with general structural properties of one-dimensional Schr"odinger operators with some absolutely continuous spectrum. The basic result says that the omega limit points of the potential under the shift map are…

Spectral Theory · Mathematics 2010-08-12 Christian Remling

We prove weighted estimates for the maximal regularity operator. Such estimates were motivated by boundary value problems. We take this opportunity to study a class of weak solutions to the abstract Cauchy problem. We also give a new proof…

Classical Analysis and ODEs · Mathematics 2009-12-23 Pascal Auscher , Andreas Axelsson

We study the spectrum of a periodic non-self-adjoint Dirac operator, and its dependence on a semiclassical parameter is also considered. Several bounds on the spectrum are obtained which provide sharp spectral enclosure estimates.…

Spectral Theory · Mathematics 2025-11-25 Jeffrey Oregero

Estimation of parameters is a pivotal task throughout science and technology. Quantum Cram\'{e}r-Rao bound provides a fundamental limit of precision allowed to achieve under quantum theory. For closed quantum systems, it has been shown how…

Quantum Physics · Physics 2014-04-01 S. Alipour , M. Mehboudi , A. T. Rezakhani

We investigate Wiener's Tauberian theorem from the perspective of limit functions, which results in several new versions of the Tauberian theorem. Based on this, we formulate and prove analogous Tauberian theorems for operators in the sense…

Functional Analysis · Mathematics 2025-09-16 Robert Fulsche , Franz Luef , Reinhard F. Werner

Given a complex Banach space $X$ and a joint spectrum for complex solvable finite dimensional Lie algebras of operators defined on $X$, we extend this joint spectrum to quasi-solvable Lie algebras of operators, and we prove the main…

Functional Analysis · Mathematics 2016-03-29 Enrico Boasso

Quasiperiodic Jacobi operators arise as mathematical models of quasicrystals and in more general studies of structures exhibiting aperiodic order. The spectra of these self-adjoint operators can be quite exotic, such as Cantor sets, and…

Spectral Theory · Mathematics 2014-12-30 Charles Puelz , Mark Embree , Jake Fillman

We prove a new upper bound for the smallest eigenvalues of the Dirac operator on a compact hypersurface of the hyperbolic space.

Differential Geometry · Mathematics 2007-05-23 Nicolas Ginoux

We derive several formulae for the spectra of the second quantization operators in abstract fermionic Fock spaces.

Functional Analysis · Mathematics 2015-06-16 Shinichiro Futakuchi , Kouta Usui

While many bounds have been proved for partial trace inequalities over the last decades for a large variety of quantities, recent problems in quantum information theory demand sharper bounds. In this work, we study optimal bounds for…

Quantum Physics · Physics 2026-01-21 Pablo Costa Rico , Pavel Shteyner

We consider Witten Laplacians associated to some non-Morse potentials. We prove Eyring-Kramers formulas for the bottom of the spectrum of these operators in the semiclassical regime and quantify the spectral gap separating these eigenvalues…

Analysis of PDEs · Mathematics 2026-01-09 Loïs Delande

We construct 1-dim difference Schr\"odinger operators with a class of Gevrey potentials such that Cantor spectrum occurs together with the estimations of open spectral gaps . The proof is based on KAM and Moser-P\"oschel argument .

Dynamical Systems · Mathematics 2025-02-12 Xuanji Hou , Li Zhang

We study the spectra of operators on periodic graphs using methods from combinatorial algebraic geometry. Our main result is a bound on the number of complex critical points of the Bloch variety, together with an effective criterion for…

Mathematical Physics · Physics 2024-02-06 Matthew Faust , Frank Sottile

In order to provide a guaranteed precision and a more accurate judgement about the true value of the Cram\'{e}r-Rao bound and its scaling behavior, an upper bound (equivalently a lower bound on the quantum Fisher information) for precision…

Quantum Physics · Physics 2017-05-04 R. Yousefjani , S. Salimi , A. S. Khorashad