RADMORE, PM;
BARNETT, SM;
STONEHAM, AM;
(1990)
CONSERVED QUANTITIES FOR THE DENSITY-MATRIX AND THE DEGREE OF STATISTICAL MIXING.
PHYS SCRIPTA
, 42
(2)
129 - 132.
10.1088/0031-8949/42/2/001.
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Abstract
We investigate the conserved quantities for a closed, N-state quantum system. A simple derivation from the equation of motion for the density matrix shows that there is an infinite number of such conserved quantities. However, only the first N of these constants of the motion are independent. These constants uniquely determine the degree of mixing in the system, which is itself conserved. We discuss the relationship between these results, the properties of Hamiltonians under unitary transformation and van Vleck's principle of spectroscopic stability.
| Type: | Article |
|---|---|
| Title: | CONSERVED QUANTITIES FOR THE DENSITY-MATRIX AND THE DEGREE OF STATISTICAL MIXING |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1088/0031-8949/42/2/001 |
| Publisher version: | http://dx.doi.org/10.1088/0031-8949/42/2/001 |
| Language: | English |
| Additional information: | Text made available to UCL Discovery by kind permission of IOP Publishing, 2012 |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences |
| URI: | https://discovery.ucl.ac.uk/id/eprint/184111 |
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