Biomedical subjects

N Manini

Publications and source records attributed to N Manini.

9 recordsLinked to original sources

PubMed2000

Off-diagonal geometric phases.

We investigate the adiabatic evolution of a set of nondegenerate eigenstates of a parametrized Hamiltonian. Their relative phase change can be related to geometric measurable quantities that extend the familiar concept of Berry phase to the evolution of more than one state. We present several physical systems where these concepts can be applied, including an experiment on microwave cavities for which off-diagonal phases can be determined from published data.

Journal Article↗

PubMed2000

Geometric phases and multiple degeneracies in harmonic resonators

In a recent experiment Lauber et al. have deformed cyclically a microwave resonator and have measured the adiabatic normal-mode wave functions for each shape along the path of deformation. The nontrivial observed cyclic phases around a threefold degeneracy were accounted for by Manolopoulos and Child within an approximate theory. However, open-path geometrical phases disagree with experiment. By solving exactly the problem, we find unsuspected extra degeneracies around the multiple one that account for the measured phase changes throughout the path. It turns out that proliferation of additional degeneracies around a multiple one is a common feature of quantum mechanics.

Journal Article↗

PubMed1996