Density matrices as polarization vectors

@article{Fano1995DensityMA,
  title={Density matrices as polarization vectors},
  author={Ugo Fano},
  journal={Rendiconti Lincei},
  year={1995},
  volume={6},
  pages={123-130}
}
  • U. Fano
  • Published 1 June 1995
  • Physics
  • Rendiconti Lincei
The concept of a density matrix originated about 1930 in the process of adapting to quantum mechanics the statistical descriptions of classical phenomena. A new light was cast on this concept when Felix Bloch formulated his NMR equation, inclusive of dissipative terms: This equation, ostensibly the time-dependent Schrödinger equation for a spin’s density matrix, governs in fact the expectation values of evolving observables, namely, the components of the spin’s polarization vector. It serves… 

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References

SHOWING 1-8 OF 8 REFERENCES

Ensemble Method in the Theory of Irreversibility

We describe a new formulation of methods introduced in the theory of irreversibility by Van Hove and Prigogine, with the purpose of making their ideas easier to understand and to apply. The main tool

Relaxation phenomena in condensed matter

Theory of the Dynamic Susceptibility of Magnetic Fluids (M. Shliomis & V. Stepanov). A Semiclassical Theory of Dielectric Relaxation and Absorption: Memory Function Approach to Extended Rotational

Pairs of two-level systems

Correlations between the orientations of two particles with spin 1/2 are formulated in terms of a complete set of operators appropriate to display the spectrum of oscillations under the influence of

Precession Equation of a Spinning Particle in Nonuniform Fields

The general equation governing the changes of orientation of a spinning particle is expressed in a compact tensorial form that represents an extension of the vector equation of Larmor precession. The