48 research outputs found
Relativistic and Radiative Corrections to the Mollow Spectrum
The incoherent, inelastic part of the resonance fluorescence spectrum of a
laser-driven atom is known as the Mollow spectrum [B. R. Mollow, Phys. Rev.
188, 1969 (1969)]. Starting from this level of description, we discuss
theoretical foundations of high-precision spectroscopy using the resonance
fluorescence light of strongly laser-driven atoms. Specifically, we evaluate
the leading relativistic and radiative corrections to the Mollow spectrum, up
to the relative orders of (Z alpha)^2 and alpha(Z alpha)^2, respectively, and
Bloch-Siegert shifts as well as stimulated radiative corrections involving
off-resonant virtual states. Complete results are provided for the hydrogen
1S-2P_{1/2} and 1S-2P_{3/2} transitions; these include all relevant correction
terms up to the specified order of approximation and could directly be compared
to experimental data. As an application, the outcome of such experiments would
allow for a sensitive test of the validity of the dressed-state basis as the
natural description of the combined atom-laser system.Comment: 20 pages, 1 figure; RevTe
Model of preparation of a craftsman in the framework of continuous vocational education
The significance of the issue under study is stipulated by a social order for targeted preparation of stafffor a craft type of companies. The aim of the article is development and approbation of structural-functional model of continuous craftsman education. The main research method of the given issue is modeling which enables to see the issue as a process of targeted, continuous and conscious acquiring of vocational competences by future craftsmen, in the course of formal, non-formal and informal education. The article presents a structural-functional model of continuous craftsman education that includes formal, non-formal and informal education and outlines a complex of organizational-pedagogical conditions contributing to implementation of this model. The contents of the article might be of interest for students of craft trades, all categories of vocational-pedagogical workers, specialists of state government institutions in the area of vocational education. © Authors
Mucin-poor mucinous tubular and spindle cell kidney cancer and clear cell renal cell carcinoma: a rare clinical case
Mucinous tubular and spindle cell carcinoma of the kidney is a rare low-grade malignant tumour and accounts for less than 1% of all renal neoplasms. The classic morphological structure of the tumor is represented by three elements: spindle cells, ducts and myxoid or mucinous stroma. This tumor is indolent with a low risk of metastasis and a favorable outcome. However, cases with relapses, metastases to regional lymph nodes, and distant metastases, which were mainly characterised by high nuclear atypia, sarcomatoid transformation and other atypical morphological features are described in the literature. Several cases of mucin-poor and mucin-free mucinous tubular and spindle cell renal cell carcinoma have also been presented, making it difficult to differentiate from other renal cell carcinomas. There are reports of cases of mucin poor mucinous tubular and spindle cell carcinoma, which were accompanied by relapses and metastases. Thus, although the tumour is indolent, careful follow-up is necessary even after radical excision. In this article, we report a rare clinical case of combination of mucin-poor mucinous tubular and spindle cell carcinoma and clear cell renal cell carcinoma of the kidney in a 50-year-old man. The results of clinical and instrumental studies, as well as the morphological features of both tumors are presented. Due to the atypical morphological structure of mucinous tubular and spindle cell carcinoma, the final diagnosis was possible using an immunohistochemical method, which demonstrated the immunohistochemical profile characteristic of this tumour
A transverse current rectification in graphene superlattice
A model for energy spectrum of superlattice on the base of graphene placed on
the striped dielectric substrate is proposed. A direct current component which
appears in that structure perpendicularly to pulling electric field under the
influence of elliptically polarized electromagnetic wave was derived. A
transverse current density dependence on pulling field magnitude and on
magnitude of component of elliptically polarized wave directed along the axis
of a superlattice is analyzed.Comment: 12 pages, 6 figure
Resonance fluorescence and Autler-Townes spectra of a two-level atom driven by two fields of equal frequencies
We study the effects of driving a two-level atom by two intense field modes that have equal frequencies but are otherwise distinguishable; the intensity of one mode is also assumed to be greater than that of the other. We calculate first the dressed states of the system, and then its resonance fluorescence and Autler-Townes absorption spectra. We find that the energy spectrum of the doubly dressed atom consists of a ladder of doublet continua. These continua manifest themselves in the fluorescence spectrum, where they produce continua at the positions of the Mellow sideband frequencies omega(L)+/-2 Omega of the strong field, and in the Autler-Townes absorption spectrum, which becomes a two-continuum doublet
Fluorescence spectrum of a two-level atom driven by a multiple modulated field
We investigate the fluorescence spectrum of a two-level atom driven by a multiple amplitude-modulated field. The driving held is modeled as a polychromatic field composed of a strong central (resonant) component and a large number of symmetrically detuned sideband fields displaced from the central component by integer multiples of a constant detuning. Spectra obtained here differ qualitatively from those observed for a single pair of modulating fields [B. Blind, P.R. Fontana, and P. Thomann, J. Phys. B 13, 2717 (1980)]. In the case of a small number of the modulating fields, a multipeaked spectrum is obtained with the spectral features located at fixed frequencies that are independent of the number of modulating fields and their Rabi frequencies. As the number of the modulating fields increases, the spectrum ultimately evolves to the well-known Mellow triplet with the sidebands shifted from the central component by an effective Rabi frequency whose magnitude depends on the initial relative phases of the components of the driving held. For equal relative phases, the effective Rabi frequency of the driving field can be reduced to zero resulting in the disappearance of fluorescence spectrum, i.e., the atom can stop interacting with the field. When the central component and the modulating fields are 180 degrees out of phase, the spectrum retains its triplet structure with the sidebands located at frequencies equal to the sum of the Rabi frequencies of the component of the driving field. Moreover, we shaw that the frequency of spontaneous emission can be controlled and switched from one frequency to another when the Rabi frequency or initial phase of the modulating fields are varied