scholarly journals COHERENT STATES AND THE CLASSICAL-QUANTUM LIMIT CONSIDERED FROM THE POINT OF VIEW OF ENTANGLEMENT

2012 ◽  
Vol 27 (01n03) ◽  
pp. 1345014 ◽  
Author(s):  
THOMAS DURT ◽  
VINCENT DEBIERRE
Keyword(s):  
Quantum System ◽  
Test Particle ◽  
Coherent States ◽  
Quantum Physics ◽  
Material Point ◽  
Point Of View ◽  
Quantum Limit ◽  
Droplet Model ◽  
Pointer States ◽  
Classical Quantum

We consider the quasi-classical situation in which a quantum system interacts with another quantum system or with a quantum environment without getting entangled with it. We show how this regime is intimately linked to three paradigms commonly used in classical, pre-quantum physics to describe particles (that is, the material point, the test particle and the diluted particle (droplet model)). This entanglement-free regime also provides a simplified insight on what is called in the decoherence approach "islands of classicality", that is, preferred bases that would be selected through evolution by a Darwinist mechanism which aims at optimizing information. We show how, under very general conditions, coherent states are natural candidates for classical pointer states. This occurs essentially because, when a (supposedly bosonic) system coherently exchanges only one quantum at a time with its (supposedly bosonic) environment, coherent states of the system do not get entangled with the environment, due to the bosonic symmetry.

scholarly journals Semi-Classical Localisation Properties of Quantum Oscillators on a Noncommutative Configuration Space

2015 ◽  
Vol 22 (04) ◽  
pp. 1550021 ◽  
Author(s):  
Fabio Benatti ◽  
Laure Gouba
Keyword(s):  
Phase Space ◽  
Configuration Space ◽  
Classical Limit ◽  
Coherent States ◽  
Point Of View ◽  
Quantum Mechanical ◽  
Wigner Functions ◽  
Quantum Mechanical Oscillators ◽  
Mechanical Oscillators ◽  
Space Noncommutativity

When dealing with the classical limit of two quantum mechanical oscillators on a noncommutative configuration space, the limits corresponding to the removal of configuration-space noncommutativity and position-momentum noncommutativity do not commute. We address this behaviour from the point of view of the phase-space localisation properties of the Wigner functions of coherent states under the two limits.

SUSY coherent states and enhanced canonical quantizations for Pauli model

2021 ◽  
pp. 2150105
Author(s):  
Jean Vignon Hounguevou ◽  
Daniel Sabi Takou ◽  
Gabriel Y. H. Avossevou
Keyword(s):  
Quantum Mechanics ◽  
Quantum Theory ◽  
Coherent States ◽  
Differential Operators ◽  
Canonical Quantization ◽  
Point Of View ◽  
Supersymmetric Quantum Mechanics ◽  
Geometric Properties

In this paper, we study coherent states for a quantum Pauli model through supersymmetric quantum mechanics (SUSYQM) method. From the point of view of canonical quantization, the construction of these coherent states is based on the very important differential operators in SUSYQM call factorization operators. The connection between classical and quantum theory is given by using the geometric properties of these states.

Build Time Analysis of Additive Manufacturing for Next Generation SLS Systems

2020 ◽  
Author(s):  
Michael Machado ◽  
Raul Fangueiro ◽  
Daniel Barros ◽  
Luís Nobre ◽  
João Bessa ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Selective Laser Sintering ◽  
Material Point ◽  
Point Of View ◽  
Efficient Production ◽  
Robust Solution ◽  
Functional Product ◽  
Build Time ◽  
Consistent Solution ◽  
Production Solutions

Abstract With the recent advances in the additive manufacturing (AM) production technologies, AM is becoming more common in today’s industry, nowadays is a normal practice to use this solution either to test a new prototype or to manufacture a functional product. The increase application is mainly due to significant developments in the production solutions of the AM. These recent developments are resulting in an increase search for new and more efficient production solutions. This search is always focused in producing more efficiently, with a greater variety of materials and produce part with better quality and proprieties. From an industrial point of view, one of the types of additive manufacturing that is increasing the percentage of use is the selective laser sintering (SLS) technologies. Although this process was first used in the mid-80’s, it has shown great developments in the recent years. This evolution of the process allowed it to become a solid solution even if it is highly time consuming, especially when compared with other types of addictive manufacturing. From the several aspects that make the SLS a robust solution is the fact that it offers a consistent solution to produce high complex part with good mechanical properties, and also the ability to use many core materials, from polymers, metal alloy, ceramics or even composites materials. Due to the fact that the production of part using SLS technologies takes a long time, shows the relevance to study the entire process in order to quantify the time spent in each stage a very important step. This study can be conducted with two major goals, in one hand to be able to predict the build time needed to complete a predetermined task, and in other hand, to improve the overall efficiency of the process based on the knowledge acquired in the previous analysis. These two aspects are important because they allow the machine operator to choose the production plan more carefully and also to know all the parameters of the process to make it more efficient. In this paper will be presented a survey of the major stages of a SLS process in order to quantify the time consumed in each one of the stages, and if possible, determine solution to reduce the time spent. To better understand the topic the paper will be divided according to the proprieties and time consumed in each of the elements of the process. In other words, it will be divided accordingly to a machine, laser and material point of view. Furthermore, this paper will be focused in the SLS process and the productions based in a polymeric powder, therefore also containing aspects related to the power source used.

scholarly journals Quantum Filtering Equations for a System Driven by Nonclassical Fields

2018 ◽  
Vol 25 (02) ◽  
pp. 1850007 ◽  
Author(s):  
Anita Da̧browska
Keyword(s):  
Quantum System ◽  
Coherent States ◽  
Single Photon ◽  
Photon Counting ◽  
Stochastic Evolution ◽  
Input Output ◽  
Nonclassical States ◽  
Cascade System ◽  
Unitary Evolution ◽  
Photon States

Using Gardiner and Collet’s input-output model and the concept of cascade system, we determine the filtering equation for a quantum system driven by light in some specific nonclassical states. The quantum system and electromagnetic field are described by making use of quantum stochastic unitary evolution. We consider two examples of the nonclassical states of field: a combination of vacuum and single photon states and a mixture of two coherent states. The stochastic evolution conditioned on the results of the photon counting and quadrature measurements is described.

Image Representation, Filtering, and Natural Computing in a Multivalued Quantum System

2016 ◽  
pp. 28-56 ◽  
Author(s):  
Sanjay Chakraborty ◽  
Lopamudra Dey
Keyword(s):  
Image Processing ◽  
Quantum System ◽  
Quantum Physics ◽  
Image Representation ◽  
Quantum Image Processing ◽  
Natural Computing ◽  
Quantum Image ◽  
Image Pixels ◽  
Classical Image ◽  
And Storage

Image processing on quantum platform is a hot topic for researchers now a day. Inspired from the idea of quantum physics, researchers are trying to shift their focus from classical image processing towards quantum image processing. Storing and representation of images in a binary and ternary quantum system is always one of the major issues in quantum image processing. This chapter mainly deals with several issues regarding various types of image representation and storage techniques in a binary as well as ternary quantum system. How image pixels can be organized and retrieved based on their positions and intensity values in 2-states and 3-states quantum systems is explained here in detail. Beside that it also deals with the topic that focuses on the clear filteration of images in quantum system to remove unwanted noises. This chapter also deals with those important applications (like Quantum image compression, Quantum edge detection, Quantum Histogram etc.) where quantum image processing associated with some of the natural computing techniques (like AI, ANN, ACO, etc.).

MAGNETIC GROUP ON THE PSEUDOSPHERE

1992 ◽  
Vol 06 (21) ◽  
pp. 3525-3537 ◽  
Author(s):  
V. BARONE ◽  
V. PENNA ◽  
P. SODANO
Keyword(s):  
Magnetic Field ◽  
Hilbert Space ◽  
Quantum Mechanics ◽  
Constant Magnetic Field ◽  
Coherent States ◽  
Compact Operators ◽  
Point Of View ◽  
Algebraic Point ◽  
Planar Limit ◽  
Discrete Part

The quantum mechanics of a particle moving on a pseudosphere under the action of a constant magnetic field is studied from an algebraic point of view. The magnetic group on the pseudosphere is SU(1, 1). The Hilbert space for the discrete part of the spectrum is investigated. The eigenstates of the non-compact operators (the hyperbolic magnetic translators) are constructed and shown to be expressible as continuous superpositions of coherent states. The planar limit of both the algebra and the eigenstates is analyzed. Some possible applications are briefly outlined.

scholarly journals Get Rid of Nonlocality from Quantum Physics

Entropy ◽  
2019 ◽  
Vol 21 (8) ◽  
pp. 806 ◽  
Author(s):  
Andrei Khrennikov
Keyword(s):  
Quantum Theory ◽  
Quantum System ◽  
Quantum Physics ◽  
Single Photon ◽  
Statistical Tests ◽  
Hidden Variables ◽  
Single Electron ◽  
Quantum Nonlocality ◽  
Single Quantum ◽  
Complementarity Principle

This paper is aimed to dissociate nonlocality from quantum theory. We demonstrate that the tests on violation of the Bell type inequalities are simply statistical tests of local incompatibility of observables. In fact, these are tests on violation of the Bohr complementarity principle. Thus, the attempts to couple experimental violations of the Bell type inequalities with “quantum nonlocality” is really misleading. These violations are explained in the quantum theory as exhibitions of incompatibility of observables for a single quantum system, e.g., the spin projections for a single electron or the polarization projections for a single photon. Of course, one can go beyond quantum theory with the hidden variables models (as was suggested by Bell) and then discuss their possible nonlocal features. However, conventional quantum theory is local.

scholarly journals Fresh and Hardened Properties of Extrusion-Based 3D-Printed Cementitious Materials: A Review

2020 ◽  
Vol 12 (14) ◽  
pp. 5628
Author(s):  
Zhanzhao Li ◽  
Maryam Hojati ◽  
Zhengyu Wu ◽  
Jonathon Piasente ◽  
Negar Ashrafi ◽  
...  
Keyword(s):  
3D Printing ◽  
Experimental Testing ◽  
Design Procedure ◽  
Cementitious Materials ◽  
Material Point ◽  
Point Of View ◽  
Open Time ◽  
Potential Benefits ◽  
3D Printed ◽  
Hardened Properties

3D-printing of cementitious materials is an innovative construction approach with which building elements can be constructed without the use of formwork. Despite potential benefits in the construction industry, it introduces various engineering challenges from the material point of view. This paper reviews the properties of extrusion-based 3D-printed cementitious materials in both fresh and hardened states. Four main properties of fresh-state printing materials are addressed: flowability, extrudability, buildability, and open time, along with hardened properties, including density, compressive strength, flexural strength, tensile bond strength, shrinkage, and cracking. Experimental testing and effective factors of each property are covered, and a mix design procedure is proposed. The main objective of this paper is to provide an overview of the recent development in 3D-printing of cementitious materials and to identify the research gaps that need further investigation.

scholarly journals Probing quantum gravity effects with quantum mechanical oscillators

2020 ◽  
Vol 74 (9) ◽  
Author(s):  
Michele Bonaldi ◽  
Antonio Borrielli ◽  
Avishek Chowdhury ◽  
Gianni Di Giuseppe ◽  
Wenlin Li ◽  
...  
Keyword(s):  
Quantum Gravity ◽  
Quantum Physics ◽  
Deformation Parameter ◽  
Thermal State ◽  
Classical Trajectory ◽  
Point Of View ◽  
Gravity Models ◽  
Gravity Effects ◽  
The Status ◽  
Mechanical Oscillators

Abstract Phenomenological models aiming to join gravity and quantum mechanics often predict effects that are potentially measurable in refined low-energy experiments. For instance, modified commutation relations between position and momentum, that account for a minimal scale length, yield a dynamics that can be codified in additional Hamiltonian terms. When applied to the paradigmatic case of a mechanical oscillator, such terms, at the lowest order in the deformation parameter, introduce a weak intrinsic nonlinearity and, consequently, deviations from the classical trajectory. This point of view has stimulated several experimental proposals and realizations, leading to meaningful upper limits to the deformation parameter. All such experiments are based on classical mechanical oscillators, i.e., excited from a thermal state. We remark indeed that decoherence, that plays a major role in distinguishing the classical from the quantum behavior of (macroscopic) systems, is not usually included in phenomenological quantum gravity models. However, it would not be surprising if peculiar features that are predicted by considering the joined roles of gravity and quantum physics should manifest themselves just on purely quantum objects. On the basis of this consideration, we propose experiments aiming to observe possible quantum gravity effects on macroscopic mechanical oscillators that are preliminary prepared in a high purity state, and we report on the status of their realization. Graphical abstract

scholarly journals ROBERTSON–SCHRÖDINGER INTELLIGENT STATES FOR TWO-BODY CALOGERO MODEL

2002 ◽  
Vol 17 (27) ◽  
pp. 1805-1812 ◽  
Author(s):  
M. DAOUD
Keyword(s):  
Quantum System ◽  
Coherent States ◽  
Calogero Model

Using the Gazeau–Klauder and Klauder–Perelomov coherent states, we derive the Robertson–Schrödinger intelligent states for two-body Calogero quantum system.

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