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In the first section we provide a solution to the M. G. Krein problem about an inner description of the space $L_2(\Sigma,H).$ In the second section we introduce the multiplicity function for an operator measure. Making use of the…

Spectral Theory · Mathematics 2007-05-23 Mark M. Malamud , Semen M. Malamud

We first give a condition for a normal operator on a Hilbert space to have no nonzero periodic points, then we give a characterization of normal operators with the whole space as periodic points. We proceed to study the structure of…

Functional Analysis · Mathematics 2025-01-23 Howen Chuah

Let $\mathbb{P}$ be the complete metric space consisting of positive invertible operators on an infinite-dimensional Hilbert space with the Thompson metric. We introduce the notion of operator means of probability measures on $\mathbb{P}$,…

Functional Analysis · Mathematics 2019-01-15 Fumio Hiai , Yongdo Lim

We extend the definition of generalized coherent states to include the case of time-dependent dispersion. We introduce a suitable operator providing displacement and dynamical rescaling from an arbitrary ground state. As a consequence,…

Quantum Physics · Physics 2007-05-23 Salvatore De Martino , Silvio De Siena , Fabrizio Illuminati

Probabilistic conditioning is concerned with the identification of a distribution of a random variable $X$ given a random variable $Y$. It is a cornerstone of scientific and engineering applications where modeling uncertainty is key. This…

Machine Learning · Statistics 2026-05-13 Panos Tsimpos , Edoardo Calvello , Ayoub Belhadji , Nicholas H. Nelsen

By using the thermo entangled state representation we solve the master equation for a dissipative cavity with Kerr medium to obtain density operators' infinite operator-sum representation}$\rho (t)…

Quantum Physics · Physics 2015-05-13 Li-yun Hu , Hong-yi Fan

Time-dependent structural reliability analysis of nonlinear dynamical systems is non-trivial; subsequently, scope of most of the structural reliability analysis methods is limited to time-independent reliability analysis only. In this work,…

Machine Learning · Statistics 2024-09-21 Navaneeth N. , Souvik Chakraborty

Based on ideas of R.W. Cross, a simplified proof is presented of the density invariance of certain operational quantities associated with bounded linear operators in normed vector spaces.

Functional Analysis · Mathematics 2007-05-23 Michael K. Kinyon

The usual Laurent expansion of the analytic tensors on the complex plane is generalized to any closed and orientable Riemann surface represented as an affine algebraic curve. As an application, the operator formalism for the $b-c$ systems…

High Energy Physics - Theory · Physics 2015-06-26 F. Ferrari , J. Sobczyk

We present a general formalism for charecterizing 2-time quantum states, describing pre- and post-selected quantum systems. The most general 2-time state is characterized by a `density vector' that is independent of measurements performed…

Quantum Physics · Physics 2014-01-30 Ralph Silva , Yelena Guryanova , Nicolas Brunner , Noah Linden , Anthony J. Short , Sandu Popescu

By definition, the Kraus representation of a harmonic oscillator suffering from the environment effect, modeled as the amplitude damping or the phase damping, is directly given by a simple operator algebra solution. As examples and…

Quantum Physics · Physics 2009-08-03 Yu-xi Liu , Sahin Kaya Ozdemir , Adam Miranowicz , Nobuyuki Imoto

It is known that local operators in quantum field theory transform in representations of ordinary global symmetry groups. The purpose of this paper is to generalise this statement to extended operators such as line and surface defects. We…

High Energy Physics - Theory · Physics 2023-06-06 Thomas Bartsch , Mathew Bullimore , Andrea Grigoletto

It is shown that the mixed states of a closed dynamics support a reduplicated symmetry, which is reduced back to the subgroup of the original symmetry group when the dynamics is open. The elementary components of the open dynamics are…

Quantum Physics · Physics 2021-09-01 Janos Polonyi , Ines Rachid

Operator systems connect operator algebra, free semialgebraic geometry and quantum information theory. In this work we generalize operator systems and many of their theorems. While positive semidefinite matrices form the underlying…

Operator Algebras · Mathematics 2025-12-12 Gemma De les Coves , Mirte van der Eyden , Tim Netzer

Standard methods of the theory of permanent state reduction are shown to offer an alternative realization of Omn\`es' project. Our proposal, as simple as Omn\`es' one, possesses closed master equation for the ensemble density operator,…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Lajos Diósi

We provide several perturbation theorems regarding closable operators on a real or complex Hilbert space. In particular we extend some classical results due to Hess--Kato, Kato--Rellich and W\"ust. Our approach involves ranges of matrix…

Functional Analysis · Mathematics 2014-09-22 Dan Popovici , Zoltán Sebestyén , Zsigmond Tarcsay

The Composite Operator Method (COM) is formulated, its internals illustrated in detail and some of its most successful applications reported. COM endorses the emergence, in strongly correlated systems (SCS), of composite operators,…

Strongly Correlated Electrons · Physics 2018-04-09 Adolfo Avella , Ferdinando Mancini

Quantum conditions on the control of dynamics of a system coupled to an environment are obtained. Specifically, consider a system initially in a system subspace $H_{0}$ of dimensionality $M_{0}$, which evolves to populate system subspaces…

Quantum Physics · Physics 2009-11-13 Lian-Ao Wu , Arjun Bharioke , Paul Brumer

The dynamics of an open quantum system can be described by a quantum operation, a linear, complete positive map of operators. Here, I exhibit a compact expression for the time reversal of a quantum operation, which is closely analogous to…

Quantum Physics · Physics 2008-04-03 Gavin E. Crooks

Given the time-evolution of an electron charge density, the local potential in Kohn-Sham time-dependent density functional theory (KS-TDDFT) can be modeled as a sum of instantaneous and dynamic contributions by assuming a certain form of…

Computational Physics · Physics 2016-11-09 R. J. Magyar