557 research outputs found
Madness and chaos in the culture of a therapeutic community
Purpose: The purpose of this paper is to explore the perceptions of staff members working in a psychiatric therapeutic community in relation to ideas of “madness” and “chaos”.
Design/methodology/approach: The paper is a qualitative study based on oral history group witness seminars.
Findings: The findings indicate that many of the participants experienced working in a therapeutic community as both exciting and unsettling; some found themselves questioning their own mental health at the time. Despite a sense of “madness” and chaos in the life of the community, there was also a feeling that it provided a containing environment for some very disturbed patients.
Originality/value: This study is unusual in drawing upon staff member’s perceptions of their own relationship to “madness” in response to being involved in the life of a therapeutic community
Ghost imaging with engineered quantum states by Hong-Ou-Mandel interference
Traditional ghost imaging experiments exploit position correlations between
correlated states of light. These correlations occur directly in spontaneous
parametric down-conversion (SPDC), and in such a scenario, the two-photon state
used for ghost imaging is symmetric. Here we perform ghost imaging using an
anti-symmetric state, engineering the two-photon state symmetry by means of
Hong-Ou-Mandel interference. We use both symmetric and anti-symmetric states
and show that the ghost imaging setup configuration results in object-image
rotations depending on the state selected. Further, the object and imaging arms
employ spatial light modulators for the all-digital control of the projections,
being able to dynamically change the measuring technique and the spatial
properties of the states under study. Finally, we provide a detailed theory
that explains the reported observations.Comment: Published version. 19 pages, 5 figure
Quantum process tomography via completely positive and trace-preserving projection
We present an algorithm for projecting superoperators onto the set of
completely positive, trace-preserving maps. When combined with gradient descent
of a cost function, the procedure results in an algorithm for quantum process
tomography: finding the quantum process that best fits a set of sufficient
observations. We compare the performance of our algorithm to the diluted
iterative algorithm as well as second-order solvers interfaced with the popular
CVX package for MATLAB, and find it to be significantly faster and more
accurate while guaranteeing a physical estimate.Comment: 13pp, 8 fig
Non-line-of-sight tracking of people at long range
A remote-sensing system that can determine the position of hidden objects has
applications in many critical real-life scenarios, such as search and rescue
missions and safe autonomous driving. Previous work has shown the ability to
range and image objects hidden from the direct line of sight, employing
advanced optical imaging technologies aimed at small objects at short range. In
this work we demonstrate a long-range tracking system based on single laser
illumination and single-pixel single-photon detection. This enables us to track
one or more people hidden from view at a stand-off distance of over 50~m. These
results pave the way towards next generation LiDAR systems that will
reconstruct not only the direct-view scene but also the main elements hidden
behind walls or corners
- …