821 research outputs found
Systemic evil and the international political imagination
In light of the persistence of discourses of atrocity in the post-Holocaust era, and with the resurgence of talk of evil that followed 11 September 2001, it is clear that the idea of evil still possesses a powerful hold upon the modern imagination. Yet, the interplay of evil and the political imagination – in particular, how different images of evil have shaped the discourses and practices of international politics – remains neglected. This article suggests that evil is depicted through three contending images within international politics – evil as individualistic, as statist and as systemic – and their corresponding forms of collective imagination – the juridical, the humanitarian and the political. It argues further that the dominance of the juridical and, to a lesser extent, the humanitarian imagination obscures our ability to imagine and respond to political evils of structural or systemic violence. Drawing on the example of global poverty, this article contends that the ability to portray and critically judge systemic evils in international politics today depends upon enriching our narratives about indefensible atrocities and reimagining our shared political responsibilities for them.PostprintPeer reviewe
Entanglement in Random Subspaces
The selection of random subspaces plays a role in quantum information theory
analogous to the role of random strings in classical information theory. Recent
applications have included protocols achieving the quantum channel capacity and
methods for extending superdense coding from bits to qubits. In addition,
random subspaces have proved useful for studying the structure of bipartite and
multipartite entanglement.Comment: Conference proceedings submission based on a talk given at QCMC04
about quant-ph/040704
Assisted Entanglement Distillation
Motivated by the problem of designing quantum repeaters, we study
entanglement distillation between two parties, Alice and Bob, starting from a
mixed state and with the help of "repeater" stations. To treat the case of a
single repeater, we extend the notion of entanglement of assistance to
arbitrary mixed tripartite states and exhibit a protocol, based on a random
coding strategy, for extracting pure entanglement. The rates achievable by this
protocol formally resemble those achievable if the repeater station could merge
its state to one of Alice and Bob even when such merging is impossible. This
rate is provably better than the hashing bound for sufficiently pure tripartite
states. We also compare our assisted distillation protocol to a hierarchical
strategy consisting of entanglement distillation followed by entanglement
swapping. We demonstrate by the use of a simple example that our random
measurement strategy outperforms hierarchical distillation strategies when the
individual helper stations' states fail to individually factorize into portions
associated specifically with Alice and Bob. Finally, we use these results to
find achievable rates for the more general scenario, where many spatially
separated repeaters help two recipients distill entanglement.Comment: 25 pages, 4 figure
- …