8,706 research outputs found
High photovoltages in ferroelectric ceramics
The short-circuit currents and photo-emfs were measured for various ceramics including barium titanate, lead metaniobate, and lead titanate. It is suggested that the emfs and currents arise from the presence of photoconductor-insulator sandwiches in the presence of space-charge-produced internal fields. Results are in agreement with the proposed theory and indicate that the ferroelectric ceramics are not only producers of high-voltage photoelectricity but a photo-battery, the polarity and magnitude of which can be switched by application of an electrical signal
Information geometry of density matrices and state estimation
Given a pure state vector |x> and a density matrix rho, the function
p(x|rho)= defines a probability density on the space of pure states
parameterised by density matrices. The associated Fisher-Rao information
measure is used to define a unitary invariant Riemannian metric on the space of
density matrices. An alternative derivation of the metric, based on square-root
density matrices and trace norms, is provided. This is applied to the problem
of quantum-state estimation. In the simplest case of unitary parameter
estimation, new higher-order corrections to the uncertainty relations,
applicable to general mixed states, are derived.Comment: published versio
Efficient Simulation of Quantum State Reduction
The energy-based stochastic extension of the Schrodinger equation is a rather
special nonlinear stochastic differential equation on Hilbert space, involving
a single free parameter, that has been shown to be very useful for modelling
the phenomenon of quantum state reduction. Here we construct a general closed
form solution to this equation, for any given initial condition, in terms of a
random variable representing the terminal value of the energy and an
independent Brownian motion. The solution is essentially algebraic in
character, involving no integration, and is thus suitable as a basis for
efficient simulation studies of state reduction in complex systems.Comment: 4 pages, No Figur
Temperature-sensitive mutant strains for isolation of additional mutants of a given site
Use of temperature-sensitive strain
The neighborhood unit concept and the shaping of land planning in the United States 1912-1968
Although one of the more well-known concepts in planning, both planning scholars and professional communities such as the New Urbanism have neglected the neighbourhood unit concept's historic influence in shaping suburban land planning norms. This paper analyzes contemporaneous professional and governmental literature in order to understand the context of land planning and development during the time that the neighbourhood unit became a leading idea. Between 1912 and 1968 the neighbourhood unit concept bridged planning, design, development and policy-making communities to improve standards in the construction of residential environments by shifting the scale of development to an area as a whole. In this time period the neighbourhood unit concept shaped land planning norms, facilitated execution of policies, framed new institutions, and became associated with the changes that it helped to bring about
Survey of the research done on art among schizophrenic children.
Thesis (Ed.M.)--Boston Universit
Karen Rothenberg’s (Not So) Secret Roles and Contributions at the U.S. National Institutes of Health
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