Coherence matrix

To avoid dephasing which would corrupt the information, the coherence matrix element p7l 72 must be transferred with the maximum efficiency into pVl, 2 ... 

The coherency matrix and the Stokes vector are not the only representations of polarization and not always the most convenient ones. Two other frequently used representations are the real so-called modified Stokes column vector given by... 

In complete analogy with the case of a plane wave, the coherency matrix, the coherency column vector, and the Stokes column vector of a spherical wave propagating in a homogeneous medium with no dispersion and losses can be defined as... 

The coherency matrix method permits the so-called dominant type of deterministic polarization transformation i.e., the corresponding deterministic part, Mueller-Jones matrix, of the initial Mueller matrix. A Jones matrix J is a 2x2 complex valued matrix containing generally eight independent parameters from the real and imaginary parts for each the four matrix elements, or seven parameters if the absolute (isotropic) phase which is not of interest for polarizations is excluded. Every Jones matrix can be transformed into an equivalent Mueller matrix but the converse assertion is not necessarily true. Between Jones J and Mueller Mj matrices that describe deterministic objects there exist a one-to-one correspondence ... 

Note that the diagonal elements of the matrix, ap and hp, correspond to the populations in the energy levels, a and b, and contain no time dependence, while the off-diagonal elements, called the coherences, contain all the time dependence. 

Figure Al.6.18. Liouville space lattice representation in one-to-one correspondence with the diagrams in figure A1.6.17. Interactions of the density matrix with the field from the left (right) is signified by a vertical (liorizontal) step. The advantage to the Liouville lattice representation is that populations are clearly identified as diagonal lattice points, while coherences are off-diagonal points. This allows innnediate identification of the processes subject to population decay processes (adapted from [37]).

Fundamentally, the conditions for lasing are detemiined unambiguously once the populations and coherences of the system density matrix are known. Yet, we have been unable to find in the literature any simple criterion for lasing in multilevel systems in temis of the system density matrix alone. Our conjecture is that entropy, as... 

A simple, non-selective pulse starts the experiment. This rotates the equilibrium z magnetization onto the v axis. Note that neither the equilibrium state nor the effect of the pulse depend on the dynamics or the details of the spin Hamiltonian (chemical shifts and coupling constants). The equilibrium density matrix is proportional to F. After the pulse the density matrix is therefore given by and it will evolve as in equation (B2.4.27). If (B2.4.28) is substituted into (B2.4.30), the NMR signal as a fimction of time t, is given by (B2.4.32). In this equation there is a distinction between the sum of the operators weighted by the equilibrium populations, F, from the unweighted sum, 7. The detector sees each spin (but not each coherence ) equally well. 

This is the operator (or matrix) equation for the coherent potential v(z). The formal expression for v(z) can be easily written. The exciton polaron is... 

Let us first consider a case of the polaron spectrum when condition (20) is fulfilled so that the nondiagonal matrix elements of the operator F can be neglected, we denote as Vinei the coherent potential in which only the inelastic scatterings are accounted. It is easy show by explicit calculations that... 

THE USE OF INTENSITY OF COHERENT AND NON-COHERENT SCATTERED RADIATION OF THE X-RAY TUBE FOR THE COMPENSATION OF MATRIX EFFECTS AT THE ANALYSIS OF SOLUTIONS BY X-RAY FLUORESCENCE... 

As a result we propose the technique of Mo, W, and Re determination in production cycle solutions with the use of peak of non-coherent scattered primary radiation in order to take into account the matrix influence on the analytical signal. The accuracy of the results was checked by the input-found technique. 

The simplest scheme that accounts for the destruction of phase coherence is the so-called stochastic interruption model [Nikitin and Korst 1965 Simonius 1978 Silbey and Harris 1989]. Suppose the process of free tunneling is interrupted by a sequence of collisions separated by time periods vo = to do After each collision the system forgets its initial phase, i.e., the off-diagonal matrix elements of the density matrix p go to zero, resulting in the density matrix p ... 

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