Localization of eigenfunctions in the stadium billiard.

We present a systematic survey of scarring and symmetry effects in the stadium billiard. The localization of individual eigenfunctions in Husimi phase space is studied first, and it is demonstrated that on average there is more localization than can be accounted for by random-matrix theory, even after removal of bouncing-ball states and visible scars. A major point of the paper is that symmetry considerations, including parity and time-reversal symmetries, enter to influence the total amount of localization. The properties of the local density of states are also investigated, as a function of phase space location. Aside from the bouncing-ball region of phase space, excess localization is found on short periodic orbits and along certain symmetry-related lines; the origin of all these sources of localization is discussed quantitatively and comparison is made with analytical predictions. Scarring is observed to be present in all the energy ranges considered. In light of our results, the excess localization in individual eigenstates is interpreted as being primarily due to symmetry effects.

Periodic orbits of nonscaling Hamiltonian systems from quantum mechanics.

Quantal (E,tau) plots are constructed from the eigenvalues of the quantum system. We demonstrate that these representations display the periodic orbits of the classical system, including bifurcations and the transition from stable to unstable. (c) 1995 American Institute of Physics.

Effect of relaxation therapy on post-myocardial infarction patients' rehabilitation.

This research measured the physical and psychosocial effects of the practice of Benson's relaxation technique by male postmyocardial infarction patients enrolled in a cardiac rehabilitation program and determined if the patient's behavioral style (Type A or Type B) was related to the outcomes. Twenty-seven subjects completed the experimental condition; 30, the control condition. Outcome measures included blood pressure, heart rate, aerobic conditioning level (MET level), and psychosocial functioning, as measured by the Sickness Impact Profile. Repeated measures analysis of variance was used to determine if relaxation therapy and/or behavior style had an effect on measures of the effectiveness of cardiac rehabilitation. The practice of relaxation was found to have a significant effect on diastolic blood pressure. Behavior style was unrelated to the outcome measures.