1,873 research outputs found
Direct dialling of Haar random unitary matrices
Random unitary matrices find a number of applications in quantum information
science, and are central to the recently defined boson sampling algorithm for
photons in linear optics. We describe an operationally simple method to
directly implement Haar random unitary matrices in optical circuits, with no
requirement for prior or explicit matrix calculations. Our physically-motivated
and compact representation directly maps independent probability density
functions for parameters in Haar random unitary matrices, to optical circuit
components. We go on to extend the results to the case of random unitaries for
qubits
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Development and Deployment of Optical Instruments to Measure Trace Atmospheric Species: I. Water Isotopologues; II. Glyoxal; III. Iodine Monoxide
Understanding future climate requires observations of trace species that can significantly influence the chemical or radiative properties of the atmosphere. The development of optical instruments, utilizing laser-systems as high-resolution light sources, for making in situ observations of trace species from either airborne- or ground-based platforms and results from field campaigns are presented. Glyoxal, the smallest -dicarbonyl, is a common product during the oxidation of volatile organic compounds. An instrument using the technique of laser-induced phosphorescence was developed to measure glyoxal at the part per trillion by volume (pptv) level from a tower in a forest canopy. The instrument was deployed as part of the Community Atmosphere-Biosphere INteractions EXperiment. The instrumental limit of detection is 3 pptv with a 1-minute acquisition time. Nearly continuous measurements of glyoxal ranging between 5 – 75 pptv were acquired throughout the campaign and vertical gradients in the forest canopy were found to be driven by elevated temperature. A sensitive instrument using laser-induced fluorescence detection was developed and deployed into remote marine environments to measure iodine monoxide (IO) where the mixing ratio is on the order of 1 – 5 pptv. The challenges and solutions of operating in this environment and results from the field and laboratory are discussed. Laboratory experiments show that IO can be generated from Laminaria digitata, a subtidal kelp species, in the presence of ozone. Observations of the isotopic composition of condensed and vapor water above a large summertime tropical convective system obtained by Hoxotope and ICOS instruments during the TC4 campaign are used to analyze the role of convection in the lower tropical transition layer (TTL). Regions of ice that are characteristic of either convective lofting or in situ condensation are encountered above an active deep tropical convective system. Ice is an important component of water transport models in the TTL, yet its isotopic composition is a relatively unconstrained parameter. The implications from the direct observations of the isotopic composition of ice during convection is explored with respect to transport models of water in the TTL.Chemistry and Chemical Biolog
Computing dynamic height from temperature profiles north of 30N in the Pacific Ocean
Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to [email protected], referencing the URI of the item.Bibliography: leaves 46-47.Not availabl
A multi-centre study of adults with learning disabilities referred to services for antisocial or offending behaviour: demographic, individual, offending and service characteristics
This study was carried out as part of a larger study commissioned by the UK Department of Health to investigate the service pathways for offenders with learning disabilities (LD). The study covered three health regions in the UK and included 477 people with LD referred to services because of antisocial or offending behaviour during a 12-month period. Data were collected concerning demographic, individual, offending behaviour and service characteristics. The findings of the study are broadly consistent with contemporary research concerning this population, particularly in relation to the nature and frequency of offending, history of offending, psychopathology, age and gender distribution. However, very few of those referred had any form of structured care plan, despite having significant offending histories, and this may have compromised early identification of their needs and communication between the health, social and other services involved
Many-particle Majorana bound states: derivation and signatures in superconducting double quantum dots
We consider two interacting quantum dots coupled by standard superconductors.
We derive an effective Hamiltonian, and show that over a wide parameter range a
degenerate ground state can be obtained. An exotique form of Majorana bound
states are supported at these degeneracies, and the system can be adiabatically
tuned to a limit in which it is equivalent to the one-dimensional wire model of
Kitaev. We give the form of a Majorana bound state in this system in the strong
interaction limit in the many-particle picture. We also study the Josephson
current in this system, and demonstrate that a double slit-like pattern emerges
in the presence of an extra magnetic field. This pattern is shown to disappear
with increasing interaction strength, which is able to be explained as the
current being carried by chargeless Majorana modes.Comment: 13 pages, 7 figures. Updated paper includes more details regarding
the derivation of the effective Hamiltonia
Referrals into services for offenders with intellectual disabilities: variables predicting community or secure provision
Background
There is a need for research to promote an understanding among service developers on why people with intellectual disabilities (ID) are referred to offender services in order for them to receive appropriate assessment and treatment. Previous studies investigating referrals into forensic ID services have concentrated on referral sources and administrative variables such as legal status.
Aims
To construct a predictive model for choice of service referral based on a comprehensive range of information about the clientele. Method We conducted a case record study of 336 people referred to community services and 141 to secure provision. We gathered information on referral source, demographics, diagnosis, index behaviour, prior problem behaviours and history of abuse.
Results
Comparisons revealed 19 candidate variables which were then entered into multivariate logistic regression. The resulting model retained six variables: community living at time of referral, physical aggression, being charged, referral from tertiary health care, diverse problem behaviour and IQ < 50, which correctly predicted the referral pathway for 85.7% of cases.
Conclusions
An index act of physical aggression and a history of diversity of problem behaviours as predictors against the likelihood of community service referral suggest that professionals have similar concerns about people with ID as they do about their more average offending peers; however, the more severe levels of ID mitigated in favour of community referral, regardless. Offenders with ID tend to be referred within levels of service rather than between them, for example, form tertiary services into generic community services
“Let this Forest For Ever Rest”: Tracking Protest and Identity in Australia’s Forests
Exploitation of natural resources has long been a flashpoint for contention in Australia. This is clear in the case of forest management, where groups advocating protection have faced off against state and industry actors. The move towards multifunctionalism that recognises different values in the management of natural resources has led to a search for alternative solutions. In the case of forestry, introduction of Regional Forest Agreements (RFA) in the 1990s sought to devolve responsibility to the States, while striking a balance between economic and environmental considerations. The aim of this paper is to identify how forest activism has developed since the RFA process began and its significance in relation to changes in land use. The paper draws on a protest event catalogue of forest-related events over the 1997-2017 period to identify the intensity, tactics and location of such actions. The findings suggest that state action has reduced the intensity of contention, in line with changes in resource management practices. However, they also point to the importance of identity and its link to the social construction of resources in determining the ability of actors to de-escalate and find solutions
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