Control of trapped-ion quantum states with optical pulses.

We present new results on the quantum control of systems with infinitely large Hilbert spaces. A control-theoretic analysis of the control of trapped-ion quantum states via optical pulses is performed. We demonstrate how resonant bichromatic fields can be applied in two contrasting ways--one that makes the system completely uncontrollable and the other that makes the system controllable. In some interesting cases, the Hilbert space of the qubit-harmonic oscillator can be made finite, and the Schrödinger equation controllable via bichromatic resonant pulses. Extending this analysis to the quantum states of two ions, a new scheme for producing entangled qubits is discovered.

Electroconvulsive therapy in adolescents: similarities to and differences from adults.

OBJECTIVE: Information on the indications, technique, and effectiveness of electroconvulsive therapy (ECT) in adolescent patients is scarce. The recommendations for the use of ECT in this age group are similar to those in adults. This study compares the experience with ECT in the two age groups in the same community psychiatric institution, which adheres to the accepted protocols for diagnosis and treatment. METHOD: The files of 24 consecutive adolescent patients treated in an ECT unit located in the center of Israel in the years 1991-1995 were retrospectively examined, and the findings were compared with those in 33 adult patients who started their ECT course on the same day. The technique for applying ECT was essentially the same in the two age groups. RESULTS: ECT was equally effective for adolescents and adults (58% in each group achieved remission). The main difference was the diagnosis for which patients were referred: most of the adolescents were in the "psychotic spectrum, whereas most of the adults were in the "affective spectrum." CONCLUSIONS: The findings support the current medical recommendations for the use of ECT in adolescents. Possible explanations for the differences in diagnosis between the two age groups are discussed.

Combat neurosis in inner-city schools.

The author studied 253 classroom teachers who were referred for psychiatric evaluation because of varying degrees of psychological stress and physical trauma. These teachers had experienced actual assault or the threat of assault in inner-city schools. The author evaluated these patients' ego functioning, attitudes, current life situations, and the presence of any predisposing factors. On the basis of these evaluations and using guidelines established in studies of combat neurosis, he recommends that individuals who experience severe occupational stress be provided psychological training to prepare them to handle stress, constant support of and access to people in administrative positions, and a mechanism for crisis intervention.