Long-range multipartite entanglement close to a first-order quantum phase transition

We provide insight into the quantum correlations structure present in strongly correlated systems beyond the standard framework of bipartite entanglement. To this aim we first exploit rotationally invariant states as a test bed to detect genuine tripartite entanglement beyond the nearest neighbor in spin-1/2 models. Then we construct in a closed analytical form a family of entanglement witnesses which provides a sufficient condition to determine if a state of a many-body system formed by an arbitrary number of spin-1/2 particles possesses genuine tripartite entanglement, independently of the details of the model. We illustrate our method by analyzing in detail the anisotropic XXZ spin chain close to its phase transitions, where we demonstrate the presence of long-range multipartite entanglement near the critical point and the breaking of the symmetries associated with the quantum phase transition.

Shortcut to Adiabaticity in the Lipkin-Meshkov-Glick Model

We study transitionless quantum driving in an infinite-range many-body system described by the Lipkin-Meshkov-Glick model. Despite the correlation length being always infinite the closing of the gap at the critical point makes the driving Hamiltonian of increasing complexity also in this case. To this aim we develop a hybrid strategy combining a shortcut to adiabaticity and optimal control that allows us to achieve remarkably good performance in suppressing the defect production across the phase transition.

An approach to determine the local boundary of small disturbance voltage stability region in a cut-set power space:基于微扰的割集电压稳定域局部边界求解方法

A new approach to determine the local boundary of voltage stability region in a cut-set power space (CVSR) is presented. Power flow tracing is first used to determine the generator-load pair most sensitive to each branch in the interface. The generator-load pairs are then used to realize accurate small disturbances by controlling the branch power flow in increasing and decreasing directions to obtain new equilibrium points around the initial equilibrium point. And, continuous power flow is used starting from such new points to get the corresponding critical points around the initial critical point on the CVSR boundary. Then a hyperplane cross the initial critical point can be calculated by solving a set of linear algebraic equations. Finally, the presented method is validated by some systems, including New England 39-bus system, IEEE 118-bus system, and EPRI-1000 bus system. It can be revealed that the method is computationally more efficient and has less approximation error. It provides a useful approach for power system online voltage stability monitoring and assessment. This work is supported by National Natural Science Foundation of China (No. 50707019), Special Fund of the National Basic Research Program of China (No. 2009CB219701), Foundation for the Author of National Excellent Doctoral Dissertation of PR China (No. 200439), Tianjin Municipal Science and Technology Development Program (No. 09JCZDJC25000), National Major Project of Scientific and Technical Supporting Programs of China During the 11th Five-year Plan Period (No. 2006BAJ03A06). ©2009 State Grid Electric Power Research Institute Press.

Facilitating a culture of responsible and effective sharing of cancer genome data

Rapid and affordable tumor molecular profiling has led to an explosion of clinical and genomic data poised to enhance the diagnosis, prognostication and treatment of cancer. A critical point has now been reached at which the analysis and storage of annotated clinical and genomic information in unconnected silos will stall the advancement of precision cancer care. Information systems must be harmonized to overcome the multiple technical and logistical barriers to data sharing. Against this backdrop, the Global Alliance for Genomic Health (GA4GH) was established in 2013 to create a common framework that enables responsible, voluntary and secure sharing of clinical and genomic data. This Perspective from the GA4GH Clinical Working Group Cancer Task Team highlights the data-aggregation challenges faced by the field, suggests potential collaborative solutions and describes how GA4GH can catalyze a harmonized data-sharing culture.

Struggles against Injustice:: Contemporary Critical Theory and Political Violence

This article investigates a significant problem in contemporary critical theory, namely its failure to address effectively the possibility that a campaign of political violence may be a legitimate means of fighting grave injustice. Having offered a working definition of ‘political violence’, I argue that critical theory should be focused on experiences of injustice rather than on ideals of justice. I then explore the reasons as to why, save for some intriguing remarks on retrospective legitimation, Jürgen Habermas has not addressed this issue directly. While Axel Honneth's recognition theory may have greater potential here, the absence of explicit consideration of the matter by him leaves considerable work to do. I introduce five questions in the concluding section that provide a starting point in setting out an appropriately stringent, normative test for claims that support violent action against injustice.

Developing critical social work in theory and in practice: child protection and communicative reason

This paper argues that a critical analysis of the ideologies that inform contemporary child care has been missing from the ‘re-focusing debate’. Such an analysis points up the necessity of reasserting a critical social work position in order to provide a basis for reconstructing practice and engaging with other social actors and their ideologies in an open and creative fashion compatible with Habermas’ aspiration of ‘communicative reason’.

Philosophy, Social Hope and Democratic Criticism:Critical Theory for a Global Age

The attempt to connect philosophy and social hope has been one of the key distinguishing features of critical theory as a tradition of enquiry. This connection has been questioned forcefully from the perspective of a post-philosophical pragmatism, as articulated by Rorty. In this article I consider two strategies that have been adopted by critical theorists in seeking to reject Rorty's suggestion that we should abandon the attempt to ground social hope in philosophical reason. We consider argumentative strategies of the philosophical anthropologist and of the rational proceduralist. Once the exchanges between Rorty and these two strands of critical theory have been reconstructed and assessed, an alternative perspective emerges. It is argued that philosophical reasoning best helps to sustain social hope in a rapidly changing world when we consider it in terms of the practice of democratic criticism.