3,464 research outputs found
Time-reversal and super-resolving phase measurements
We demonstrate phase super-resolution in the absence of entangled states. The
key insight is to use the inherent time-reversal symmetry of quantum mechanics:
our theory shows that it is possible to \emph{measure}, as opposed to prepare,
entangled states. Our approach is robust, requiring only photons that exhibit
classical interference: we experimentally demonstrate high-visibility phase
super-resolution with three, four, and six photons using a standard laser and
photon counters. Our six-photon experiment demonstrates the best phase
super-resolution yet reported with high visibility and resolution.Comment: 4 pages, 3 figure
Demonstration of a simple entangling optical gate and its use in Bell-state analysis
We demonstrate a new architecture for an optical entangling gate that is
significantly simpler than previous realisations, using partially-polarising
beamsplitters so that only a single optical mode-matching condition is
required. We demonstrate operation of a controlled-Z gate in both
continuous-wave and pulsed regimes of operation, fully characterising it in
each case using quantum process tomography. We also demonstrate a
fully-resolving, nondeterministic optical Bell-state analyser based on this
controlled-Z gate. This new architecture is ideally suited to guided optics
implementations of optical gates.Comment: 4 pages, 3 figures. v2: additional author, improved data and figures
(low res), some other minor changes. Accepted for publication in PR
Natural Connections Demonstration Project, 2012- 2016: Final Report
This report presents the key findings from the Natural Connections Demonstration Project, that aimed to encourage teachers to take curricular learning outdoors. The project was commissioned by DEFRA, Natural England and Historic England, and delivered by a team at Plymouth University. 125 schools contributed to the evaluation which found that: 1. schools most likely to engage with outdoor learning displayed strong leadership and were open-minded about trying new things 2. schools reported a statistically-significant increase in the amount of time spent on outdoor learning activity across the project 3. Schools adopted many different models of outdoor learning 4. Schools invested time, goodwill, energy and funding in outdoor learning 5. Over 90 per cent of responding schools agreed that outdoor learning was useful for curriculum delivery 6. Outdoor learning had positive impacts for teachers and pupils 7. the project model of distributed independent brokerage was found to have the capacity to unlock latent demand for outdoor learning in schools, and to support schools in embedding low-cost outdoor learning practice
Quantum metrology at the Heisenberg limit with ion traps
Sub-Planck phase-space structures in the Wigner function of the motional
degree of freedom of a trapped ion can be used to perform weak force
measurements with Heisenberg-limited sensitivity. We propose methods to
engineer the Hamiltonian of the trapped ion to generate states with such small
scale structures, and we show how to use them in quantum metrology
applications.Comment: 10 pages, 6 figure
High Density Faraday Cup Array or Other Open Trench Structures and Method of Manufacture Thereof
A detector array and method for making the detector array. The detector array includes a substrate including a plurality of trenches formed therein, and a plurality of collectors electrically isolated from each other, formed on the walls of the trenches, and configured to collect charged particles incident on respective ones of the collectors and to output from the collectors signals indicative of charged particle collection. In the detector array, adjacent ones of the plurality of trenches are disposed in a staggered configuration relative to one another. The method forms in a substrate a plurality of trenches across a surface of the substrate such that adjacent ones of the trenches are in a staggered sequence relative to one another, forms in the plurality of trenches a plurality of collectors, and connects a plurality of electrodes respectively to the collectors
The extraordinary Hall effect in coherent epitaxial tau (Mn,Ni)Al thin films on GaAs
Ultrathin coherent epitaxial films of ferromagnetic tau(Mn,Ni)0.60Al0.40 have been grown by molecular beam epitaxy on GaAs substrates. X-ray scattering and cross-sectional transmission electron microscopy measurements confirm that the c axis of the tetragonal tau unit cell is aligned normal to the (001) GaAs substrate. Measurements of the extraordinary Hall effect (EHE) show that the films are perpendicularly magnetized, exhibiting EHE resistivities saturating in the range of 3.3-7.1 muOMEGA-cm at room temperature. These values of EHE resistivity correspond to signals as large as +7 and -7 mV for the two magnetic states of the film with a measurement current of 1 mA. Switching between the two magnetic states is found to occur at distinct field values that depend on the previously applied maximum field. These observations suggest that the films are magnetically uniform. As such, tau(Mn,Ni)Al films may be an excellent medium for high-density storage of binary information
Ample consumption period available until use-by dates: a potential, marketing position for store brands
Traditionally store brands in Australia are viewed with suspicion in regard to their quality and are usually purchased because of the "value for money" that they offer. Australian supermarket majors are considering introducing a new suite of store brands in the higher price brackets. The danger of moving upscale however is that these store brands are relinquishing their value for money appeal and will come head to head with the manufactured brands. Store brands will now require some quality dimension to compete. This paper after studying the attitudes and behavioural response of grocery shoppers to use by dates, is proposing that that the promise of "generous" use-by dates as a surrogate for quality, could be considered as a positioning plank to promote store brands as alternatives to manufactured brands. Logit analysis is employed to explain shoppers' perception and response to use-by dates, of products that they regularly buy, and of alternative products which they have never bought before if the use-by dates of their regular items are perceived to be too shor
The Value of Mind-Body Connection in Physical Activity for Older People.
Exercise that targets balance and strength is proven to prevent falls in older age. The Successful AGEing yoga trial is the first large randomized controlled trial to assess the impact of yoga on falls in people aged ≥60 years. We conducted a realist process evaluation to explain the strong participant engagement observed using interviews (21 participants and three yoga instructors) and focus groups (12 participants and four yoga instructors). Results showed that relaxation, breathing, and yoga's mind-body connection created a satisfying internal focus on bodily sensation which was valued by participants. The mechanisms of mindfulness and embodiment appeared to facilitate this. Mindfulness and embodiment are also linked to, and enhance engagement with, other forms of physical activity. By focusing creatively on these mechanisms, we can develop a range of programs that target improvements in physical and mental health (including reducing falls and fear of falls) and appeal to older people
Analytic Solution for the Critical State in Superconducting Elliptic Films
A thin superconductor platelet with elliptic shape in a perpendicular
magnetic field is considered. Using a method originally applied to circular
disks, we obtain an approximate analytic solution for the two-dimensional
critical state of this ellipse. In the limits of the circular disk and the long
strip this solution is exact, i.e. the current density is constant in the
region penetrated by flux. For ellipses with arbitrary axis ratio the obtained
current density is constant to typically 0.001, and the magnetic moment
deviates by less than 0.001 from the exact value. This analytic solution is
thus very accurate. In increasing applied magnetic field, the penetrating flux
fronts are approximately concentric ellipses whose axis ratio b/a < 1 decreases
and shrinks to zero when the flux front reaches the center, the long axis
staying finite in the fully penetrated state. Analytic expressions for these
axes, the sheet current, the magnetic moment, and the perpendicular magnetic
field are presented and discussed. This solution applies also to
superconductors with anisotropic critical current if the anisotropy has a
particular, rather realistic form.Comment: Revtex file and 13 postscript figures, gives 10 pages of text with
figures built i
Faraday Cup Array Integrated with a Readout IC and Method for Manufacture Thereof
A detector array and method for making the detector array. The array includes a substrate including a plurality of trenches formed therein, and includes a plurality of collectors electrically isolated from each other, formed on the walls of the trenches, and configured to collect charge particles incident on respective ones of the collectors and to output from said collectors signals indicative of charged particle collection. The array includes a plurality of readout circuits disposed on a side of the substrate opposite openings to the collectors. The readout circuits are configured to read charge collection signals from respective ones of the plurality of collectors
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