Strong, fast pulses, called ‘‘bang–bang’’ controls can be used to eliminate the effects of system-environment interactions. This method for preventing errors in quantum information processors is treated here in a geometric setting which leads to an intuitive perspective. Using this geometric description, we clarify the notion of group symmetrization as an averaging technique, provide a geometri...

In this paper we use an optimal control approach to analyze time dependent enzyme concentrations that minimize the transition time of a metabolic pathway while respecting the natural constraints imposed by a limited biosynthetical capacity. Our main result states that, under appropriate assumptions, at each time instant all the available enzyme production capacity is allocated to a single react...

A principal technical result of this paper is that the onedimensional heat equation with boundary control is exactly null-controllable with control restricted to an arbitrary set E ⊂ [0, T ] of positive measure. A general abstract argument is presented to show that this implies the ‘bangbang’ property for time-optimal controls — i.e., such a control can take only extreme values of (the hull of)...

In this article, we propose a new paradigm of control, called a maximum-hands-off control. A hands-off control is defined as a control that has a much shorter support than the horizon length. The maximum-hands-off control is the minimum-support (or sparsest) control among all admissible controls. We first prove that a solution to an L-optimal control problem gives a maximum-handsoff control, an...

A teoria do Big Bang corresponde ao modelo explicativo início Universo a partir de um ponto (singularidade) elevada densidade e temperatura que começa expandir- se, criando-se o espaço-tempo. Sendo seguido pelo período inflação cósmica, dominado pela radiação outro matéria (principalmente escura) até momento atual, por uma energia escura, permite explicar história nosso observável. O é bem test...

The cyclic theory of the universe is a radical alternative to the standard big bang/inflationary scenario that offers a new approach for resolving the homogeneity, isotropy, and flatness problems and generating a nearly scale-invariant spectrum of fluctuations. The original formulation of the cyclic model was based on the picture suggested by M-theory in which the observable universe lies on a ...

A variety of new physics scenarios allow for neutrinos to up-scatter into a heavy neutral lepton state. For range couplings and neutrino energies, the may travel some distance before decaying visible final states. When both up-scattering decay occur within detector volume, these "double bang" events produce distinctive phenomenology with very low background. In this work, we first consider curr...

BACKGROUND The loud Snoring, Tiredness, Observed apnea, high blood Pressure (STOP)-Body mass index (BMI), Age, Neck circumference, and gender (Bang) questionnaire is a validated screening tool for identifying obstructive sleep apnea in surgical patients. However, the predictive performance of the STOP-Bang score in obese and morbidly obese patients remains unknown. METHODS Preoperative patien...