202 research outputs found
A Bell-type test of energy-time entangled qutrits
We have performed a Bell-type test for energy-time entangled qutrits. A
method of inferring the Bell violation in terms of an associated interference
visibility is derived. Using this scheme we obtained a Bell value of , representing a violation of above the limit for local
variables. The scheme has been developed for use at telecom wavelengths and
using proven long distance quantum communication architecture to optimize the
utility of this high dimensional entanglement resource.Comment: replaced lost acknowledement
Stationary state entanglement and total correlation of two qubits or qutrits
We investigate the mutual information and entanglement of stationary state of
two locally driven qubits under the influence of collective dephasing. It is
shown that both the mutual information and the entanglement of two qubits in
the stationary state exhibit damped oscillation with the scaled action time
of the local external driving field. It means that we can control
both the entanglement and total correlation of the stationary state of two
qubits by adjusting the action time of the driving field. We also consider the
influence of collective dephasing on entanglement of two qutrits and obtain the
sufficient condition that the stationary state is entangled.Comment: 5 pages, 2 figures, RevTex
Successful remote treatment of a client with Hikikomori using internet-delivered cognitive therapy for social anxiety disorder: a case report
Hikikomori (prolonged social withdrawal) has been discussed as a hidden worldwide epidemic and a significant social and healthcare issue. Social anxiety disorder is the most common psychiatric disorder preceding the onset of Hikikomori. Although studies exist suggesting the effectiveness of family-support interventions, little is known about psychotherapeutic approaches for Hikikomori individuals. Here, we present a case of Hikikomori wherein an internet-delivered cognitive therapy for social anxiety disorder (iCT-SAD) worked effectively in improving the client’s social anxiety symptoms and social interaction behaviors. This case study demonstrates the principle that evidence-based psychological interventions focusing on social anxiety can be effective for clients with Hikikomori. Furthermore, the online mode of treatment delivery, along with a variety of relevant modules, may facilitate clients’ engagement with treatment at home. The findings suggest that iCT-SAD might be a promising option for Hikikomori clients who have social anxiety problems, within the recommended stepped-intervention approach
Waveguide-based OPO source of entangled photon pairs
In this paper we present a compact source of narrow-band energy-time
entangled photon pairs in the telecom regime based on a Ti-indiffused
Periodically Poled Lithium Niobate (PPLN) waveguide resonator, i.e. a waveguide
with end-face dielectric multi-layer mirrors. This is a monolithic doubly
resonant Optical Parametric Oscillator (OPO) far below threshold, which
generates photon pairs by Spontaneous Parametric Down Conversion (SPDC) at
around 1560nm with a 117MHz (0.91 pm)- bandwidth. A coherence time of 2.7 ns is
estimated by a time correlation measurement and a high quality of the entangled
states is confirmed by a Bell-type experiment. Since highly coherent
energy-time entangled photon pairs in the telecom regime are suitable for long
distance transmission and manipulation, this source is well suited to the
requirements of quantum communication.Comment: 13 page
Decoherence-based exploration of d-dimensional one-way quantum computation
We study the effects of amplitude and phase damping decoherence in
d-dimensional one-way quantum computation (QC). Our investigation shows how
information transfer and entangling gate simulations are affected for d>=2. To
understand motivations for extending the one-way model to higher dimensions, we
describe how d-dimensional qudit cluster states deteriorate under environmental
noise. In order to protect quantum information from the environment we consider
the encoding of logical qubits into physical qudits and compare entangled pairs
of linear qubit-cluster states with single qudit clusters of equal length and
total dimension. Our study shows a significant reduction in the performance of
one-way QC for d>2 in the presence of Markovian type decoherence models.Comment: 8 pages, 11 figures, RevTeX
Exploring the perspectives of ‘young adults’ (18–24) who have been in formal care and their experiences of attending a socially prescribed community allotment gardening group
Introduction: Young adults who have experienced periods of time being ‘in care’ are one of the most socially deprived populations within society, with their needs largely unmet and often not fully understood. Despite the significant attempts to invest in community-based ‘social prescribing’ interventions to address such health inequalities, there is a dearth of understanding regarding how such occupation-based community groups are experienced by this particular population. This UK based qualitative study aimed to explore the experiences of young adult ‘Care Leavers’ regarding their participation in a socially prescribed community gardening group.
Method: Semi-structured online interviews were conducted with six young care leavers aged between 18 and 24 years who regularly participated in a community gardening group. Interviews were recorded transcribed verbatim and analysed Braun and Clarke’s Thematic Analysis process by two researchers to maximise validity.
Findings: Four key themes emerged: ‘Social belonging and connection’, ‘A safe space’, ‘Sense of achievement from active engagement’ and ‘The facilitatory aspects of nature’. The findings suggested nature-based co-occupation within a local group, enhanced social capital, self-identity and wellbeing.
Conclusion: This study supports the emerging scope of using community occupation-based interventions with young adult ‘Care Leavers’ and offers an insight into their particular needs
Nonlinear interaction between two heralded single photons
Harnessing nonlinearities strong enough to allow two single photons to
interact with one another is not only a fascinating challenge but is central to
numerous advanced applications in quantum information science. Currently, all
known approaches are extremely challenging although a few have led to
experimental realisations with attenuated classical laser light. This has
included cross-phase modulation with weak classical light in atomic ensembles
and optical fibres, converting incident laser light into a non-classical stream
of photon or Rydberg blockades as well as all-optical switches with attenuated
classical light in various atomic systems. Here we report the observation of a
nonlinear parametric interaction between two true single photons. Single
photons are initially generated by heralding one photon from each of two
independent spontaneous parametric downconversion sources. The two heralded
single photons are subsequently combined in a nonlinear waveguide where they
are converted into a single photon with a higher energy. Our approach
highlights the potential for quantum nonlinear optics with integrated devices,
and as the photons are at telecom wavelengths, it is well adapted to
applications in quantum communication.Comment: 4 pages, 4 figure
Acknowledging religion in cognitive behavioural therapy: the effect on alliance, treatment expectations and credibility in a video-vignette study
Objectives: Developing mental health services which are accessible and acceptable to those from minority backgrounds continues to be a priority. In the United Kingdom, individuals who identify with a religion are underrepresented in Talking Therapies services as compared to those with no religion. This necessitates an understanding of how therapy is perceived. This online study explored the impact of explicitly acknowledging religion on anticipated alliance, treatment credibility and expectations of therapy in a non-clinical sample of British Muslims.
Methods: A video-vignette experimental design was used in which participants who self-reported as either high or low in religiosity were randomly allocated to receiving information about cognitive behavioural therapy either with or without an explicit mention of religion as a value in the therapeutic process.
Results: One hundred twenty-nine British Muslim adults aged 18–70+ years from various ethnic backgrounds participated in the study. Between-subjects ANOVAs showed that scores on the perceived credibility of therapy and treatment expectations were significantly higher when religion was explicitly mentioned by the ‘therapist’, but that acknowledging religion did not impact upon anticipated alliance.
Conclusions: These findings suggest that mentioning religion as a value to be considered in therapy has some positive impacts upon how therapy is perceived by British Muslims. Although video vignettes do not provide insight into the complexity of actual therapeutic encounters, acknowledging religion in mental health services more broadly remains an important consideration for improving equity of access and may bear relevance to other minoritized groups
Mixed State Entanglement: Manipulating Polarisation-Entangled Photons
There has been much discussion recently regarding entanglement
transformations in terms of local filtering operations and whether the optimal
entanglement for an arbitrary two-qubit state could be realised. We introduce
an experimentally realisable scheme for manipulating the entanglement of an
arbitrary state of two polarisation entangled qubits. This scheme is then used
to provide some perspective to the mathematical concepts inherent in this field
with respect to a laboratory environment. Specifically, we look at how to
extract enhanced entanglement from systems with a fixed rank and in the case
where the rank of the density operator for the state can be reduced, show how
the state can be made arbitrarily close to a maximally entangled pure state. In
this context we also discuss bounds on entanglement in mixed states.Comment: 12 pages, 10 figure
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