Compact Neural Networks based on the Multiscale Entanglement Renormalization Ansatz

This paper demonstrates a method for tensorizing neural networks based upon an efficient way of approximating scale invariant quantum states, the Multi-scale Entanglement Renormalization Ansatz (MERA). We employ MERA as a replacement for the fully connected layers in a convolutional neural network and test this implementation on the CIFAR-10 and CIFAR-100 datasets. The proposed method outperforms factorization using tensor trains, providing greater compression for the same level of accuracy and greater accuracy for the same level of compression. We demonstrate MERA layers with 14000 times fewer parameters and a reduction in accuracy of less than 1% compared to the equivalent fully connected layers, scaling like O(N).Comment: 8 pages, 2 figure

Hierarchical quantum classifiers

Quantum circuits with hierarchical structure have been used to perform binary classification of classical data encoded in a quantum state. We demonstrate that more expressive circuits in the same family achieve better accuracy and can be used to classify highly entangled quantum states, for which there is no known efficient classical method. We compare performance for several different parameterizations on two classical machine learning datasets, Iris and MNIST, and on a synthetic dataset of quantum states. Finally, we demonstrate that performance is robust to noise and deploy an Iris dataset classifier on the ibmqx4 quantum computer

Electrically driven spin resonance in a bent disordered carbon nanotube

Resonant manipulation of carbon nanotube valley-spin qubits by an electric field is investigated theoretically. We develop a new analysis of electrically driven spin resonance exploiting fixed physical characteristics of the nanotube: a bend and inhomogeneous disorder. The spectrum is simulated for an electron valley-spin qubit coupled to a hole valley-spin qubit and an impurity electron spin, and features that coincide with a recent measurement are identified. We show that the same mechanism allows resonant control of the full four-dimensional spin-valley space.Comment: 11 pages, 7 figure

Existence of Majorana fermions for M-branes wrapped in space and time

We show that it is possible to define Majorana (s)pinor fields on M-branes which have been identified under the action of the antipodal map on the adS factor of the throat geometry, or which have been wrapped on two-cycles of arbitrary genus. This is an important consistency check, since it means that one may still take the generators of supertranslations in superspace to transform as Majorana fermions under the adjoint action of $Spin(10,1)$, even though the antipodally identified M2-brane is {\it not} space-orientable. We point out that similar conclusions hold for any p-branes which have the generic (adS)$~{\times}~$(Sphere) throat geometry.Comment: 10 pages REVTe

Dam-break reflection

The unsteady reflection of dam-break flow along a horizontal channel by a remote barrier is modelled using the nonlinear shallow water equations. The interaction generates an upstream moving bore that connects the collapsing reservoir of fluid to a rapidly deepening fluid layer adjacent to the barrier. These motions are modified when the fluid is released into a channel containing a pre-wetted layer, because the oncoming flow is itself headed by a bore that alters the initial reflection. Solutions for these flows are calculated using quasi-analytical techniques that utilise the method of characteristics and the hodograph transformation of the governing equations, and the results are validated by comparison with direct numerical integration of the shallow water equations. The analytical solutions enable the precise identification of dynamical features in the flow, including the onset and development of discontinuous solutions that are manifest as bores, as well as their long term behaviour, the rate at which energy is dissipated, and for flows generated from the release of a finite reservoir, the maximum depth of the fluid layer at the barrier

Factors influencing effective performance of multi-cultural construction project teams

As a result of globalization, one of the major issues affecting the success of a construction project would be the formation of a multi-cultural project team. As construction project leaders continue to lead global, multi-cultural projects, there is a demand for managing a workforce that is more diverse than ever. The multi-generational workforce has distinct views on work ethic, communication and incentives; finding common ground is essential. This study examines how cultural differences could impact upon multi-cultural team performance. Postal questionnaires were sent to project leaders in Kenya and UK. The results indicate that different approaches in multi-cultural performances consist of seven key impacts: communication techniques, smoothness of handover, teamwork, issue resolution, joint decision making, people selection, people selection and prioritization. The findings suggest that project leaders managing multi-cultural construction project teams need to have the attributes to building trust among team members, provide good planning and institute good communication techniques. Our results on how cultural differences impact multi-cultural construction project teams can help construction organizations identify likely areas of potential divergence on multi-cultural projects, and researchers to identify areas of future research

Addressing cultural issues when managing multicultural construction project teams

This paper examines the nature of multicultural project teams and their place in the global business environment. It highlights some of the issues regarding cultural complexity that exist in multicultural project teams and argues that, getting multicultural project teams to work effectively across international boundaries has become a major concern. The inclination is likely to continue and the future of business will increasingly depend on doing projects effectively in different cultural environments. This is difficult enough to achieve where the team is situated in the same office located close to the construction site. But it is much more difficult for multicultural global projects that have a range of diverse companies involved, are widely separated geographically and that have very different organisational and regional cultures. This study explored the efficacy of multicultural team working in heavy construction engineering in Kenya and the UK. The research employed both qualitative and quantitative methodologies to capture all the relevant experiences of senior managers. Using evidence from the two sets of participants, the study highlights some of the barriers to effective multicultural team working and demonstrates the critical importance of building cultural understanding through leadership. The findings revealed a number of determinants, attributes, and variables that either facilitated or limited the effectiveness of multicultural team working

The unsteady overtopping of barriers by gravity currents and dam-break flows

The collision of a gravitationally-driven horizontal current with a barrier following release from a confining lock is investigated using a shallow water model of the motion, together with a sophisticated boundary condition capturing the local interaction. The boundary condition permits several overtopping modes: supercritical, subcritical, and blocked flow. The model is analysed both mathematically and numerically to reveal aspects of the unsteady motion and to compute the proportion of the fluid trapped upstream of the barrier. Several problems are treated. Firstly, the idealised problem of a uniform incident current is analysed to classify the unsteady dynamical regimes. Then, the extreme regimes of a very close or distant barrier are tackled, showing the progression of the interaction through the overtopping modes. Next, the trapped volume of fluid at late times is investigated numerically, demonstrating regimes in which the volume is determined purely by volumetric considerations, and others where transient inertial effects are significant. For a Boussinesq gravity current, even when the volume of the confined region behind the barrier is equal to the fluid volume, $30\%$ of the fluid escapes the domain, and a confined volume $3$ times larger is required for the overtopped volume to be negligible. For a subaerial dam-break flow, the proportion that escapes is in excess of $60\%$ when the confined volume equals the fluid volume, and a barrier as tall as the initial release is required for negligible overtopping. Finally, we compare our predictions to experiments, showing a good agreement across a range of parameters.Comment: 28 pages, 16 figures, preprin