scholarly journals QSES's and the Quantum Jump

2001 ◽  
Vol 56 (1-2) ◽  
pp. 228-229
Author(s):  
David Salgado ◽  
José Luis Sánchez-Gómez
Keyword(s):  
Hilbert Space ◽  
Markov Property ◽  
Quantum Systems ◽  
Point Of View ◽  
Stochastic Methods ◽  
Stochastic Evolution ◽  
Quantum Jumps ◽  
Practical Point ◽  
Quantum Jump ◽  
Evolution Scheme

Abstract The stochastic methods in Hilbert space have been used both from a fundamental and a practical point of view. The result reported here concerns the application of these methods to model the evolution of quantum systems and does not enter into the question of their fundamental or practical status. It can easily be stated as follows: Once a quantum stochastic evolution scheme is assumed, the incompatibility of the Markov property with the notion of quantum jumps is easily established

scholarly journals Paths of unitary access to exceptional points

2021 ◽  
Vol 2038 (1) ◽  
pp. 012026
Author(s):  
Miloslav Znojil
Keyword(s):  
Hilbert Space ◽  
Phase Transitions ◽  
Quantum Phase Transitions ◽  
Quantum Systems ◽  
Point Of View ◽  
Explicit Description ◽  
Direct Access ◽  
Exceptional Point ◽  
Exceptional Points ◽  
Innovative Idea

Abstract With an innovative idea of acceptability and usefulness of the non-Hermitian representations of Hamiltonians for the description of unitary quantum systems (dating back to the Dyson’s papers), the community of quantum physicists was offered a new and powerful tool for the building of models of quantum phase transitions. In this paper the mechanism of such transitions is discussed from the point of view of mathematics. The emergence of the direct access to the instant of transition (i.e., to the Kato’s exceptional point) is attributed to the underlying split of several roles played by the traditional single Hilbert space of states ℒ into a triplet (viz., in our notation, spaces K and ℋ besides the conventional ℒ ). Although this explains the abrupt, quantum-catastrophic nature of the change of phase (i.e., the loss of observability) caused by an infinitesimal change of parameters, the explicit description of the unitarity-preserving corridors of access to the phenomenologically relevant exceptional points remained unclear. In the paper some of the recent results in this direction are summarized and critically reviewed.

PASSIVITY OF GROUND STATES OF QUANTUM SYSTEMS

2005 ◽  
Vol 17 (01) ◽  
pp. 1-14 ◽  
Author(s):  
WALTER F. WRESZINSKI
Keyword(s):  
Hilbert Space ◽  
Quantum System ◽  
Ground State ◽  
Quantum Systems ◽  
Point Of View ◽  
Cyclic Vector ◽  
Vector State ◽  
Unitary Evolution ◽  
C Algebra ◽  
Local Perturbations

We consider a quantum system described by a concrete C*-algebra acting on a Hilbert space ℋ with a vector state ω induced by a cyclic vector Ω and a unitary evolution Ut such that UtΩ = Ω, ∀t ∈ ℝ. It is proved that this vector state is a ground state if and only if it is non-faithful and completely passive. This version of a result of Pusz and Woronowicz is reviewed, emphasizing other related aspects: passivity from the point of view of moving observers and stability with respect to local perturbations of the dynamics.

scholarly journals A geometric Hamiltonian description of composite quantum systems and quantum entanglement

2015 ◽  
Vol 12 (07) ◽  
pp. 1550069 ◽  
Author(s):  
Davide Pastorello
Keyword(s):  
Hilbert Space ◽  
Phase Space ◽  
Quantum Entanglement ◽  
Hamiltonian Formulation ◽  
Classical Mechanics ◽  
Hamiltonian Formalism ◽  
Quantum Systems ◽  
Point Of View ◽  
Entanglement Measure ◽  
Hamiltonian Description

Finite-dimensional Quantum Mechanics can be geometrically formulated as a proper classical-like Hamiltonian theory in a projective Hilbert space. The description of composite quantum systems within the geometric Hamiltonian framework is discussed in this paper. As summarized in the first part of this work, in the Hamiltonian formulation the phase space of a quantum system is the Kähler manifold given by the complex projective space P(H) of the Hilbert space H of the considered quantum theory. However the phase space of a bipartite system must be P(H1 ⊗ H2) and not simply P(H1) × P(H2) as suggested by the analogy with Classical Mechanics. A part of this paper is devoted to manage this problem. In the second part of the work, a definition of quantum entanglement and a proposal of entanglement measure are given in terms of a geometrical point of view (a rather studied topic in recent literature). Finally two known separability criteria are implemented in the Hamiltonian formalism.

Tertiary Nitrification Pilot Plants on Parisian Waste Water

1990 ◽  
Vol 22 (1-2) ◽  
pp. 347-352 ◽  
Author(s):  
C. Paffoni ◽  
B. Védry ◽  
M. Gousailles
Keyword(s):  
Waste Water ◽  
Metropolitan Area ◽  
Fixed Bed ◽  
Point Of View ◽  
Operating Conditions ◽  
Research Center ◽  
Daily Output ◽  
Practical Point ◽  
Fixed Bed Reactors

The Paris Metropolitan area, which contains over eight million inhabitants, has a daily output of about 3 M cu.meters of wastewater, the purification of which is achieved by SIAAP (Paris Metropolitan Area Sewage Service) in both Achères and Valenton plants. The carbon pollution is eliminated from over 2 M cu.m/day at Achères. In order to improve the quality of output water, its tertiary nitrification in fixed-bed reactors has been contemplated. The BIOFOR (Degremont) and BIOCARBONE (OTV) processes could be tested in semi-industrial pilot reactors at the CRITER research center of SIAAP. At a reference temperature of 13°C, the removed load is approximately 0.5 kg N NH4/m3.day. From a practical point of view, it may be asserted that in such operating conditions as should be at the Achères plant, one cubic meter of filter can handle the tertiary nitification of one cubic meter of purified water per hour at an effluent temperature of 13°C.

scholarly journals On the Design of Outdoor Leader-Follower UAV-Formation Controllers from a Practical Point of View

IEEE Access ◽  
2021 ◽  
pp. 1-1
Author(s):  
Lucas Vago Santana ◽  
Alexandre Santos Brandao ◽  
Mario Sarcinelli-Filho
Keyword(s):  
Point Of View ◽  
Practical Point

Quantitative Analysis of Microstructure and Modeling of Sintering

2009 ◽  
Vol 624 ◽  
pp. 1-18 ◽  
Author(s):  
Jean Marc Chaix
Keyword(s):  
Image Analysis ◽  
Input Data ◽  
3D Imaging ◽  
Point Of View ◽  
Size Distributions ◽  
Practical Point ◽  
The Past ◽  
Modeling Techniques ◽  
Mean Size ◽  
Sintering Mechanisms

Microstructure is the key scale to understand and describe sintering mechanisms and their consequences at the macroscopic level. As modeling techniques are continuously developing, the need for input data and comparison with more and more accurate descriptions of the evolution is expected to create a growing demand for quantitative microstructure data. Image analysis is the classic way to get these data. This paper reviews the practical use and progresses of this old technique in the sintering literature during the past and recent years. The place of basic tools and more recent ones, such as 3D imaging, are discussed from a practical point of view accounting from sintering models needs: mean size and size distributions in pores and grains, homogeneity, sintering trajectories…

Technology and the management imagination

2005 ◽  
Vol 13 (3) ◽  
pp. 533-563 ◽  
Author(s):  
Fred Phillips
Keyword(s):  
Corporate Culture ◽  
Point Of View ◽  
Local Culture ◽  
Social Consensus ◽  
Practical Point ◽  
Research Questions ◽  
Crisis Managers

This paper explores the evolution of the techno-management imagination (TMI). This is the process by which, in times of crisis, managers think not just out of the box, but out of the very reality in which the box resides. Tacit social consensus, also known as corporate culture, can lead to a shared, implicit, and incorrect view that certain actions are impossible. TMI transcends local culture, accessing technological solutions that are unknown and/or unimagined. Members of the organization tend to call such solutions “magic”. The paper looks at social, perceptual, and managerial aspects of magic from a practical point of view that is grounded in research. It examines the risks of TMI, and concludes with suggested perspectives and research questions for management scientists and cognitive scientists.

Sign in / Sign up

Export Citation Format

Share Document