2d QUANTUM DOTS IN POLYCHROMATIC RADIATION FIELDS: EFFECTS OF FREQUENCY MIXING, PHASE AND ANHARMONICITY ON THE FREEZING OF DYNAMICS

2010 ◽  
Vol 09 (01) ◽  
pp. 293-314
Author(s):  
SUBHASREE GHOSH ◽  
PARIKSHIT MANDAL ◽  
MANAS GHOSH
Keyword(s):  
Radiation Field ◽  
Time Dynamics ◽  
Radiation Fields ◽  
Single Carrier ◽  
Long Time ◽  
Oscillation Frequencies ◽  
Quartic Anharmonicity ◽  
External Time ◽  
Polychromatic Radiation ◽  
Insight Into

We explore the pattern of time evolution of a harmonically confined single carrier 2-d quantum dot when an external time varying polychromatic radiation field is switched on. The radiation field is composed of four mutually prime "nonresonant" frequencies. For given strengths of the confining field, cyclotron frequency, intensities, and oscillation frequencies of the external field, the system reveals a counter-intuitive long-time dynamics leading to a kind of localization in the unperturbed state space. The presence of cubic and quartic anharmonicity in the confining fields, and phase shifts in the external radiation fields, bring in new features in the dynamics. Time dependent Hellman–Feynmann theorem is invoked to gain insight into the frequency resolved absorption spectrum.

scholarly journals Infrared Problem vs Gauge Choice: Scattering of Classical Dirac Field

2021 ◽  
Author(s):  
Andrzej Herdegen
Keyword(s):  
Free Field ◽  
Asymptotic Completeness ◽  
Dirac Field ◽  
Free Evolution ◽  
Wave Operators ◽  
Radiation Fields ◽  
Scattering Wave ◽  
Long Time ◽  
Free Fields ◽  
External Time

AbstractWe consider the Dirac equation for the classical spinor field placed in an external, time-dependent electromagnetic field of the form typical for scattering settings: $$F=F^\mathrm{ret}+F^\mathrm{in}=F^\mathrm{adv}+F^\mathrm{out}$$ F = F ret + F in = F adv + F out , where the current producing $$F^{\mathrm{ret}/\mathrm{adv}}$$ F ret / adv has past and future asymptotes homogeneous of degree $$-3$$ - 3 , and the free fields $$F^{\mathrm{in}/\mathrm{out}}$$ F in / out are radiation fields produced by currents with similar asymptotic behavior. We show the existence of the electromagnetic gauges in which the particle has ‘in’ and ‘out’ asymptotic states approaching free field states, with no long-time corrections of the free dynamics. Using a special Cauchy foliation of the spacetime, we show in this context the existence and asymptotic completeness of the wave operators. Moreover, we define a special ‘evolution picture’ in which the free evolution operator has well-defined limits for $$t\rightarrow \pm \infty $$ t → ± ∞ ; thus the scattering wave operators do not need the free evolution counteraction.

Long-time dynamics of a class of nonlocal extensible beams with time delay

2021 ◽  
pp. 108128652110194
Author(s):  
Fengjuan Meng ◽  
Cuncai Liu ◽  
Chang Zhang
Keyword(s):  
Time Delay ◽  
Stability Property ◽  
Beam Equation ◽  
Exponential Attractors ◽  
Time Dynamics ◽  
Bounded Smooth Domain ◽  
Finite Dimensional ◽  
Long Time ◽  
Bounded Smooth ◽  
Long Time Dynamics

This work is devoted to the following nonlocal extensible beam equation with time delay: [Formula: see text] on a bounded smooth domain [Formula: see text]. The main purpose of this paper is to consider the long-time dynamics of the system. Under suitable assumptions, the quasi-stability property of the system is established, based on which the existence and regularity of a finite-dimensional compact global attractor are obtained. Moreover, the existence of exponential attractors is proved.

scholarly journals Singular Limit and Long-Time Dynamics of Bresse Systems

2017 ◽  
Vol 49 (4) ◽  
pp. 2468-2495 ◽  
Author(s):  
To Fu Ma ◽  
Rodrigo Nunes Monteiro
Keyword(s):  
Singular Limit ◽  
Time Dynamics ◽  
Long Time ◽  
Long Time Dynamics

Long-time dynamics via direct summation of infinite continued fractions

1992 ◽  
Vol 68 (11) ◽  
pp. 1637-1640 ◽  
Author(s):  
Zhi-Xiong Cai ◽  
Surajit Sen ◽  
S. D. Mahanti
Keyword(s):  
Continued Fractions ◽  
Time Dynamics ◽  
Long Time ◽  
Long Time Dynamics ◽  
Direct Summation

Bulinga izpausmes skolā: kriminoloģiskās problēmas

2021 ◽  
pp. 258-268
Author(s):  
Aldona Kipāne
Keyword(s):  
Theoretical Analysis ◽  
Research Methods ◽  
Complex Analysis ◽  
Health And Safety ◽  
Document Analysis ◽  
Violent Behaviour ◽  
Long Time ◽  
Empirical Research Methods ◽  
Insight Into

The article gives an insight into criminological problems of bullying in school phenomena. Although the term “bullying” is a modern word, such behaviour has been known for a long time. Bullying is a manifestation of violent behaviour, which threatens the victim's health and safety. The aim of this article is to describe and analyse bullying as a form of expression of violence, showing the criminological aspects of this phenomenon. To achieve the aim of the article the following tasks are defined: to provide the theoretical and practical framework of the research phenomenon, to study and evaluate certain elements of the criminological characterization of the bullying: the description of a victim and a perpetrator, the evaluation of factors and directions of prevention. Theoretical analysis methods such as deconstruction, descriptive and complex analysis, and empirical research methods – document analysis, comparison and compilation were employed in this study.

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