Purification through Zeno-like Measurements

A series of frequent measurements on a quantum system (Zeno-like measurements) is shown to result in the ``purification'' of another quantum system in interaction with the former. Even though the measurements are performed on the former system, their effect drives the latter into a pure state, irrespectively of its initial (mixed) state, provided certain conditions are satisfied.Comment: REVTeX4, 4 pages, 1 figure; to be published in Phys. Rev. Lett. (2003

Acupuncture fails to reduce but increases anaesthetic gas required to prevent movement in response to surgical incision.

Background: Acupuncture is used for clinical pain relief but has not been evaluated under clinical anaesthesia. This study was designed to compare movement in response to surgical incision in anaesthetized patients subjected to electro-acupuncture (EA) or sham procedures. Our hypothesis was that EA stimulation would reduce the requirements for anaesthetic gas. Methods: Forty-six healthy women, scheduled for laparoscopic sterilization at a Swedish county hospital, were randomized to have either the electro-acupuncture (n = 23) or sham (n = 23) procedure between the induction of general anaesthesia and the start of surgery. The minimal alveolar concentration (MAC) of sevoflurane required to prevent neck or major limb movements in response to surgical incision was determined in each group of patients. Results: The MAC for sevoflurane was found to be higher in the group given acupuncture than in the control group (2.1 ± 0.3% vs. 1.8 ± 0.4%; P = 0.008). Conclusion: Electro-acupuncture given during general anaesthesia with sevoflurane failed to reduce but instead increased the clinical need for anaesthetic gas, possibly by reducing the anaesthetic effect of sevoflurane and/or by facilitating nociceptive transmission and/or reflex activity

Survival law in a potential model

The radial equation of a simple potential model has long been known to yield an exponential decay law in lowest order (Breit-Wigner) approximation. We demonstrate that if the calculation is extended to fourth order the decay law exhibits the quantum Zeno effect. This model has further been studied numerically to characterize the extra exponential time parameter which compliments the lifetime. We also investigate the inverse Zeno effect.Comment: 16 pages, 2 tables, 3 figures, AMS-Te

Quantum Zeno subspaces

The quantum Zeno effect is recast in terms of an adiabatic theorem when the measurement is described as the dynamical coupling to another quantum system that plays the role of apparatus. A few significant examples are proposed and their practical relevance discussed. We also focus on decoherence-free subspaces.Comment: 5 pages, 1 figure, to be published in Phys. Rev. Let

Zeno dynamics yields ordinary constraints

The dynamics of a quantum system undergoing frequent measurements (quantum Zeno effect) is investigated. Using asymptotic analysis, the system is found to evolve unitarily in a proper subspace of the total Hilbert space. For spatial projections, the generator of the "Zeno dynamics" is the Hamiltonian with Dirichlet boundary conditions.Comment: 6 page

Restauração ecológica e serviços ecossistêmicos na agricultura familiar.

bitstream/item/220617/1/Doc-490-Restauracao.pd

J., C., G., C. , I., S. Kopp

Freigang F, Klett S, Kopp S. Pragmatic multimodality: Effects of nonverbal cues of focus and certainty in a virtual human. In: Beskow J, Peters C, Castellano G, O'Sullivan C, Leite I, Kopp S, eds. The Seventeenth International Conference on Intelligent Virtual Agents (IVA 2017). Lecture Notes in Computer Science. Vol 10498. Springer International Publishing; 2017: 142-155