4,463 research outputs found
McStas and Mantid integration
McStas and Mantid are two well established software frameworks within the
neutron scattering community. McStas has been primarily used for simulating the
neutron transport of instruments, while Mantid has been primarily used for data
reduction. We report here the status of our work done on the interoperability
between the instrument simulation software McStas and the data reduction
software Mantid. This provides a demonstration of how to successfully link
together two software that otherwise have been developed independently, and in
particular here show how this has been achieved for an instrument simulation
software and a data reduction software. This paper will also provide examples
of some of the expected future enhanced analysis that can be achieved from
combining accurate instrument and sample simulations with software for
correcting raw data. In the case of this work for raw data collected at large
scale neutron facilities.Comment: 17 pages, 12 figures, POSTPRINT with proofs of article submitted to
Journal of Neutron Researc
Comparing superconducting and permanent magnets for magnetic refrigeration
We compare the cost of a high temperature superconducting (SC) tape-based solenoid with a permanent magnet (PM) Halbach cylinder for magnetic refrigeration. Assuming a five liter active magnetic regenerator volume, the price of each type of magnet is determined as a function of aspect ratio of the regenerator and desired internal magnetic field. It is shown that to produce a 1 T internal field in the regenerator a permanent magnet of hundreds of kilograms is needed or an area of superconducting tape of tens of square meters. The cost of cooling the SC solenoid is shown to be a small fraction of the cost of the SC tape. Assuming a cost of the SC tape of 6000 /kg, the superconducting solenoid is shown to be a factor of 0.3-3 times more expensive than the permanent magnet, for a desired field from 0.5-1.75 T and the geometrical aspect ratio of the regenerator. This factor decreases for increasing field strength, indicating that the superconducting solenoid could be suitable for high field, large cooling power applications
Increasing complexity with quantum physics
We argue that complex systems science and the rules of quantum physics are
intricately related. We discuss a range of quantum phenomena, such as
cryptography, computation and quantum phases, and the rules responsible for
their complexity. We identify correlations as a central concept connecting
quantum information and complex systems science. We present two examples for
the power of correlations: using quantum resources to simulate the correlations
of a stochastic process and to implement a classically impossible computational
task.Comment: 22 pages, 4 figure
Distributed Quantum Computation Based-on Small Quantum Registers
We describe and analyze an efficient register-based hybrid quantum
computation scheme. Our scheme is based on probabilistic, heralded optical
connection among local five-qubit quantum registers. We assume high fidelity
local unitary operations within each register, but the error probability for
initialization, measurement, and entanglement generation can be very high
(~5%). We demonstrate that with a reasonable time overhead our scheme can
achieve deterministic non-local coupling gates between arbitrary two registers
with very high fidelity, limited only by the imperfections from the local
unitary operation. We estimate the clock cycle and the effective error
probability for implementation of quantum registers with ion-traps or
nitrogen-vacancy (NV) centers. Our new scheme capitalizes on a new efficient
two-level pumping scheme that in principle can create Bell pairs with
arbitrarily high fidelity. We introduce a Markov chain model to study the
stochastic process of entanglement pumping and map it to a deterministic
process. Finally we discuss requirements for achieving fault-tolerant operation
with our register-based hybrid scheme, and also present an alternative approach
to fault-tolerant preparation of GHZ states.Comment: 22 Pages, 23 Figures and 1 Table (updated references
Magneto-elastic coupling in La(Fe, Mn, Si)<sub>13</sub>H<i>y</i> within the Bean-Rodbell model
First order magnetic phase transition materials present a large magnetocaloric effect around the transition temperature, where these materials usually undergo a large volume or structural change. This may lead to some challenges for applications, as the material may break apart during field change, due to high internal stresses. A promising magnetocaloric material is La(Fe, Mn, Si)13Hy, where the transition temperature can be controlled through the Mn amount. In this work we use XRD measurements to evaluate the temperature dependence of the unit cell volume with a varying Mn amount. The system is modelled using the Bean-Rodbell model, which is based on the assumption that the spin-lattice coupling depends linearly on the unit cell volume. This coupling is defined by the model parameter Ρ, where for Ρ > 1 the material undergoes a first order transition and for Ρâ ⤠1 a second order transition. We superimpose a Gaussian distribution of the transition temperature with a standard deviation
Ď
T
0
, in order to model the chemical inhomogeneity. Good agreement is obtained between measurements and model with values of Ρâ âź 1.8 and Ď(T0) = 1.0 K
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