The Structure of Qubit Unextendible Product Bases

Unextendible product bases have been shown to have many important uses in quantum information theory, particularly in the qubit case. However, very little is known about their mathematical structure beyond three qubits. We present several new results about qubit unextendible product bases, including a complete characterization of all four-qubit unextendible product bases, which we show there are exactly 1446 of. We also show that there exist p-qubit UPBs of almost all sizes less than $2^p$.Comment: 20 pages, 3 tables, 7 figure

La veritat de la Viquipèdia

What does it mean to assert that Wikipedia has a relation to truth? That there is, despite regular claims to the contrary, an entire apparatus of truth in Wikipedia? In this article, I show that Wikipedia has in fact two distinct relations to truth: one which is well known and forms the basis of existing popular and scholarly commentaries, and another which refers to equally well-known aspects of Wikipedia, but has not been understood in terms of truth. I demonstrate Wikipedia’s dual relation to truth through a close analysis of the Neutral Point of View core content policy (and one of the project’s “Five Pillars”). I conclude by indicating what is at stake in the assertion that Wikipedia has a regime of truth and what bearing this has on existing commentaries

Devil in a New Dress: Reframing as an Alternative Method of Motivated Reasoning

Much research has been conducted in the field of motivated reasoning, with most of this work focused on the tendency of motivated reasoners to reject counterarguments out of hand, the so-called disconfirmation bias. The objective of this work is markedly different. Borrowing from the prodigious body of work on framing, this investigation suggests an alternative route of motivated reasoning: when presented with a counterargument, subjects engage in motivated reasoning not by wholly rejecting the counter, but by reframing their attitudes so as to reduce the importance of the challenged belief. To this end, we conducted a series of experiments centered around challenging popular political beliefs and measuring the impact of the challenge on the receiver. This was accomplished first by conducting surveys to uncover prevailing political beliefs around several topics ranging from gun control to the legalization of prostitution. With the most common beliefs clearly established, we then conducted an experiment in which these beliefs were challenged through the creation of specifically tailored and previously evaluated counterarguments. Experimental subjects were asked to provide their (positive or negative) attitude toward a given political topic, and then asked to rank and rate the four most common beliefs surrounding that topic – with the first ranked belief representing the one the subject felt was most important. This belief was then challenged, and after a period – a week in the first trial, and ten minutes in the second trial – the subjects were asked to repeat their rankings and ratings of the offered beliefs. The results showed virtually no attitude change resulting from these challenges, but a significant number of subjects lowered their first-ranked belief after having been challenged. We interpret this behavior as engaging in motivated reasoning via reframing. Further research to determine when individuals engage in motivated reasoning via disconfirmation vs. reframing is needed, but these early results suggest that reframing is a legitimate alternative route through which individuals maintain their attitudes in the face of challenges.No embargoAcademic Major: Political Scienc

Universal Communication, Universal Graphs, and Graph Labeling

We introduce a communication model called universal SMP, in which Alice and Bob receive a function f belonging to a family ?, and inputs x and y. Alice and Bob use shared randomness to send a message to a third party who cannot see f, x, y, or the shared randomness, and must decide f(x,y). Our main application of universal SMP is to relate communication complexity to graph labeling, where the goal is to give a short label to each vertex in a graph, so that adjacency or other functions of two vertices x and y can be determined from the labels ?(x), ?(y). We give a universal SMP protocol using O(k^2) bits of communication for deciding whether two vertices have distance at most k in distributive lattices (generalizing the k-Hamming Distance problem in communication complexity), and explain how this implies a O(k^2 log n) labeling scheme for deciding dist(x,y) ? k on distributive lattices with size n; in contrast, we show that a universal SMP protocol for determining dist(x,y) ? 2 in modular lattices (a superset of distributive lattices) has super-constant ?(n^{1/4}) communication cost. On the other hand, we demonstrate that many graph families known to have efficient adjacency labeling schemes, such as trees, low-arboricity graphs, and planar graphs, admit constant-cost communication protocols for adjacency. Trees also have an O(k) protocol for deciding dist(x,y) ? k and planar graphs have an O(1) protocol for dist(x,y) ? 2, which implies a new O(log n) labeling scheme for the same problem on planar graphs

‘Put on your boots and Harrington!’: The ordinariness of 1970s UK punk dress

In 2013, the Metropolitan Museum hosted an exhibition of punk-inspired fashion entitled Punk: Chaos to Couture. The exhibition emphasized the ‘spectacular’ elements of the subculture, reflecting a narrative that dominates accounts of punk dress, whereby it is presented as a site of art school creativity and disjuncture with the past. This is an important aspect of punk dress, but photos of bands and audiences reveal that there was much more to British punk style in the 1970s than what was being sold on London’s King’s Road. Heeding calls to trouble the boundary between the spectacular and the ordinary in subculture studies, this article looks at the ordinariness of 1970s British punk dress, arguing that we should understand punk dress in terms of mass-market commodities, not just customization and designer fashion. Many of these commodities were worn by the skinheads who preceded punk, and this article explores this subcultural continuity by focusing on the role of the Dr.Marten boot and the Harrington jacketin first- and second-wave British punk dress.It does so through discussion of the Cockney Rejects, the 1979 BBC television dramatization of the Sham 69 album That’s Life and the Undertones.Peer reviewedFinal Accepted Versio