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The existence of incompatibility is one of the most fundamental features of quantum theory, and can be found at the core of many of the theory's distinguishing features, such as Bell inequality violations and the no-broadcasting theorem. A…

Quantum Physics · Physics 2018-06-27 Sergey N. Filippov , Teiko Heinosaari , Leevi Leppäjärvi

Based on ideas of quantum theory of open systems we propose the consistent approach to the formulation of logic of plausible propositions. To this end we associate with every plausible proposition diagonal matrix of its likelihood and…

Quantum Physics · Physics 2015-06-05 E. D. Vol

Given a vector space of microscopic quantum observables, density functional theory is formulated on its dual space. A generalized Hohenberg-Kohn theorem and the existence of the universal energy functional in the dual space are proven. In…

Nuclear Theory · Physics 2009-09-25 G. Rosensteel , Ts. Dankova

An observable on a quantum structure is any $\sigma$-homomorphism of quantum structures from the Borel $\sigma$-algebra of the real line into the quantum structure which is in our case a monotone $\sigma$-complete effect algebras with the…

Mathematical Physics · Physics 2015-06-04 Anatolij Dvurečenskij

Accurate characterization of the noise influencing a quantum system of interest has far-reaching implications across quantum science, ranging from microscopic modeling of decoherence dynamics to noise-optimized quantum control. While the…

We propose observable bounds for Gaussian illumination to maximize the signal-to-noise ratio, which minimizes the discrimination error between the presence and absence of a low-reflectivity target using Gaussian states. The observable…

The Glauber-Sudarshan diagonal `weight' function provides a natural divide between the quantum-optical notion of classical and nonclassical states of continuous variables systems. Based on this demarcation, a channel is said to be…

Quantum Physics · Physics 2016-04-28 Krishna Kumar Sabapathy

Quantum Gaussian channels are fundamental models for communication and information processing in continuous-variable quantum systems. This work addresses both foundational aspects and physical implementation pathways for these channels.…

Quantum Physics · Physics 2025-05-08 Repana Devendra , Tiju Cherian John , K. Sumesh

We introduce open-loop quantum control protocols for characterizing the spectral properties of non-Gaussian noise, applicable to both classical and quantum dephasing environments. The basic idea is to engineer a multi-dimensional frequency…

Quantum Physics · Physics 2016-04-20 Leigh M. Norris , Gerardo A. Paz-Silva , Lorenza Viola

The notion coexistence of quantum observables was introduced to describe the possibility of measuring two or more observables together. Here we survey the various different formalisations of this notion and their connections. We review…

Quantum Physics · Physics 2011-01-04 P. Busch , J. Kiukas , P. Lahti

A linear open quantum system consisting of a harmonic oscillator linearly coupled to an infinite set of independent harmonic oscillators is considered; these oscillators have a general spectral density function and are initially in a…

Quantum Physics · Physics 2009-11-06 Esteban Calzetta , Albert Roura , Enric Verdaguer

We give necessary and sufficient conditions for a Gaussian quantum channel to have a dilation involving a passive, i.e., number-preserving unitary. We then establish a normal form of such channels: any passively dilatable channel is the…

Quantum Physics · Physics 2017-04-27 Martin Idel , Robert Koenig

We study the non-Gaussian character of quantum optomechanical systems evolving under the fully nonlinear optomechanical Hamiltonian. By using a measure of non-Gaussianity based on the relative entropy of an initially Gaussian state, we…

Quantum Physics · Physics 2020-03-26 Sofia Qvarfort , Alessio Serafini , André Xuereb , Dennis Rätzel , David Edward Bruschi

We consider several observers who monitor different parts of the environment of a single quantum system and use their data to deduce its state. We derive a set of conditional stochastic master equations that describe the evolution of the…

Quantum Physics · Physics 2009-11-07 Jacek Dziarmaga , Diego A. R. Dalvit , Wojciech H. Zurek

Quantum theory has the intriguing feature that is inconsistent with noncontextual hidden variable models, for which the outcome of a measurement does not depend on which other compatible measurements are being performed concurrently. While…

Quantum Physics · Physics 2015-08-20 Hong-Yi Su , Jing-Ling Chen , Yeong-Cherng Liang

The Schr\"odinger wavefunction is ubiquitous in quantum mechanics, quantum chemistry, and bosonic quantum information theory. Its zero-set for fermionic systems is well-studied and central for determining chemical properties, yet for…

Quantum Physics · Physics 2025-08-04 Sacha Cerf , Clara Wassner , Jack Davis , Francesco Arzani , Ulysse Chabaud

We prove that under the Gaussian measure, half-spaces are uniquely the most noise stable sets. We also prove a quantitative version of uniqueness, showing that a set which is almost optimally noise stable must be close to a half-space. This…

Probability · Mathematics 2013-02-25 Elchanan Mossel , Joe Neeman

We address the dynamics of a bosonic system coupled to either a bosonic or a magnetic environment, and derive a set of sufficient conditions that allow one to describe the dynamics in terms of the effective interaction with a classical…

Coherence is a cornerstone of quantum theory and a prerequisite for the advantage of quantum technologies. In recent work, the notion of coherence with respect to a general quantum measurement (POVM) was introduced and embedded into a…

Quantum Physics · Physics 2021-03-31 Felix Bischof , Hermann Kampermann , Dagmar Bruß

In the space of quantum channels, we establish the geometry that allows us to make statistical predictions about relative volumes of entanglement breaking channels among all the Gaussian quantum channels. The underlying metric is…

Quantum Physics · Physics 2019-12-11 Katarzyna Siudzińska , Kimmo Luoma , Walter T. Strunz