938 research outputs found
Measurement as Absorption of Feynman Trajectories: Collapse of the Wave Function Can be Avoided
We define a measuring device (detector) of the coordinate of quantum particle
as an absorbing wall that cuts off the particle's wave function. The wave
function in the presence of such detector vanishes on the detector. The trace
the absorbed particles leave on the detector is identifies as the absorption
current density on the detector. This density is calculated from the solution
of Schr\"odinger's equation with a reflecting boundary at the detector. This
current density is not the usual Schr\"odinger current density. We define the
probability distribution of the time of arrival to a detector in terms of the
absorption current density. We define coordinate measurement by an absorbing
wall in terms of 4 postulates. We postulate, among others, that a quantum
particle has a trajectory. In the resulting theory the quantum mechanical
collapse of the wave function is replaced with the usual collapse of the
probability distribution after observation. Two examples are presented, that of
the slit experiment and the slit experiment with absorbing boundaries to
measure time of arrival. A calculation is given of the two dimensional
probability density function of a free particle from the measurement of the
absorption current on two planes.Comment: 20 pages, latex, no figure
Double valley Dirac fermions for 3D and 2D HgCdTe with strong asymmetry
In this paper the possibility to bring about the double- valley Dirac
fermions in some quantum structures is predicted. These quantum structures are:
strained 3D HgCdTe topological insulator (TI) with strong interface
inversion asymmetry and the asymmetric HgCdTe double quantum wells
(DQW). The numerical analysis of the dispersion relation for 3D TI
HgCdTe for the proper Cd ()-content of in the
HgCdTe-compound clearly show that the inversion symmetry breaking
together with the unaxial tensile strain causes splitting each of Dirac nodes
(two belonging to two interfaces) into two in the proximity of -point.
The similar effects can be obtained for asymmetric HgCdTe DQW with
the proper content of Cd and proper width of the quantum wells. The aim of this
work is to explore the inversion symmetry breaking in 3D TI and 2D DQWs mixed
HgCdTe-systems. It is shown that this symmetry breaking leads to the dependence
of carriers energy vs quasi-momentum similar to that of Weyl fermions.Comment: arXiv admin note: text overlap with arXiv:1605.09214 by other author
The concept of Index for the Assessment of Regulations' Significance (IARS) in regulatory impact evaluation
This article aims to present the concept of the Index for the Assessment of Regulations’ Significance as a tool used in parliamentary regulatory impact assessment, with a special focus on expost assessment. The Index is an element of the broadly defined economic analysis of law, which can facilitate a more effective scrutiny of parliamentary lawmaking. The Index also enables theRIA (Regulatory Impact Assessment) to be verified by the act originator at the stage of the ex-ante regulatory impact assessment. Furthermore, the Index can also serve as a tool for conducting an analysis of the overall legislation process employed in parliament over a given period of time, on the basis of the adopted legal and substantive criteria.Celem artykułu jest przedstawienie koncepcji wskaźnika oceny istotności regulacji jako narzędzia do wykorzystania w parlamentarnej ocenie skutków regulacji, ze szczególnym uwzględnieniem oceny ex-post. Wskaźnik jest elementem szeroko rozumianej ekonomicznej analizy prawa, która umożliwić może skuteczniejszą kontrolę stanowienia prawa przez parlamenty. Wskaźnik umożliwia także weryfikację RIA przeprowadzonego przez projektodawcę na etapie oceny skutków regulacji ex-ante. Ponadto wskaźnik służyć może do przeprowadzenia analizy całego procesu legislacyjnego w parlamencie w danym okresie na podstawie przyjętych kryteriów prawnych i merytorycznych
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